Disable VRO pump?
Richard Eriksson
Having an '85, 70 hp Evinrude motor bored and rebuilt. It has the
automatic VRO oil system and is used on a 17' boat with built in
30 gallon gas tank. Several people have suggested disabling the
VRO pump and mixing the oil in the gas tank. On the other hand,
I have also been advised that Evinrude has redesigned the VRO pump
several times, the latest design is very reliable and I should include
a new style pump with the engine rebuild and use the VRO system.
I'd like to use the VRO (if reliable) because of the built in gas
tank and conveinence. The boat is used for ocean fishing; trolling
for extended periods of time, with WOT used to beat the thunderstorms
on the way back to the dock.
Recommendations? Thanks!
Dick Eriksson
Carl G. Craver
Unless the VRO pump is fairly new and the motor has "died" of unrelated
causes, I always include a new VRO pump in the estimate when I rebuild a
powerhead.
My advise would be to have a new VRO installed and use it.
Carl G. Craver
Evinru...@msn.com
Richard Eriksson wrote in message <358D9A...@vptec.com>...
billgran
Richard Eriksson wrote:
>
> Having an '85, 70 hp Evinrude motor bored and rebuilt. It has the
> automatic VRO oil system and is used on a 17' boat with built in
> 30 gallon gas tank. Several people have suggested disabling the
> VRO pump and mixing the oil in the gas tank. On the other hand,
> I have also been advised that Evinrude has redesigned the VRO pump
> several times, the latest design is very reliable and I should include
> a new style pump with the engine rebuild and use the VRO system.
>
> I'd like to use the VRO (if reliable) because of the built in gas
> tank and conveinence. The boat is used for ocean fishing; trolling
> for extended periods of time, with WOT used to beat the thunderstorms
> on the way back to the dock.
>
> Recommendations? Thanks!
>
> Dick Eriksson
The "mechanics" that you mentioned are probably not currently factory
trained and do not understand the system. The VRO came out in 1984, 14
years ago, and more than 1 million engines from 40 thru 300 horsepower
are equipt with oil injection. It is the only system that has a no-oil
flow warning, other engines can "fry" without any indication from the
oil system.
Install the new VRO and update the tank filter, hose, bulb, and clamps.
A QUALIFIED tech will know what to do. You will also get a 1 year parts
and labor warranty. If you install the new warning horn also, you will
have the same reliability as a new engine.
Bill Grannis
service manager
Dave Brown
Richard Eriksson wrote:
> I'd like to use the VRO (if reliable) because of the built in gas
> tank and conveinence. The boat is used for ocean fishing; trolling
> for extended periods of time, with WOT used to beat the thunderstorms
> on the way back to the dock.
> Recommendations? Thanks!
Go with the new pump kit (and horn). Make sure the mechanics are factory
trained OMC guys doing the work.
--
Regards,
Dave Brown
Brown's Marina
http://www.brownsmarina.on.ca/
Richard C. Eriksson
Richard Eriksson wrote:
>
> Having an '85, 70 hp Evinrude motor bored and rebuilt. It has the
> automatic VRO oil system and is used on a 17' boat with built in
> 30 gallon gas tank. Several people have suggested disabling the
> VRO pump and mixing the oil in the gas tank. On the other hand,
> I have also been advised that Evinrude has redesigned the VRO pump
> several times, the latest design is very reliable and I should include
> a new style pump with the engine rebuild and use the VRO system.
>
> tank and conveinence. The boat is used for ocean fishing; trolling
> for extended periods of time, with WOT used to beat the thunderstorms
> on the way back to the dock.
>
> Recommendations? Thanks!
>
Gentlemen:
Thanks for your input. I have requested that a new VRO pump, of latest
design, be installed.
Dick Eriksson
K Smith
Richard,
It's good to see the OMC dealer team have now "come out" & declared
their vested interest, very good & well done. (I might as well be hung for a
sheep as a lamb)
My "opinion" is stay right away from OMC "factory trained machanics"
Some are but, most are not "qualified" in any other manner than their OMC
training, which is purely OMC parts replacement training, a bit like a kid doing
all the McDonalds "training courses", hanging the achiever plaque on a
restaurant wall & calling themselves a chef.
If the guy you're dealing with ONLY has an OMC factory plaque hanging on
his wall run away, you're about to be advised by someone who is not qualified as
anything but an OMC parts re-fitter, re-marketer & big marker-upper of OMC
spruiked product.
N.B. This is only my "opinion", which I have formed over many years by
observing numerous OMC dealers, their "factory trained" so-called mechanics &
mostly the performance/design of their engines.
I'm obliged to give the facts on why I've formed & voiced this "opinion"
& I genuinely look forward to fact based peer review which I hope will follow,
so;
(i) Early days of 2 stroke OBs, tank mixed oil at from 25:1 to 50:1, but
mostly 50:1, motors performed OK & lasted only OK but not too many catastrophic
failures.
(ii) The "problems with the early tank mixed engines were; (a) Excessive
oil & fuel at idle which fouled plugs, (b) Inconsistent fuel/oil mix either by
the owner or through settlement in the tank, (c) Difficult idle control
because of (a) & (b), (d) What catastrophic failures did occur, they were
mostly related to pre-ignition in larger HP engines, from too much oil which
led to the fuel's octane being greatly reduced. (e) OBs, particularly
larger HP when used extensively for trolling suffered serious plug fouling &
overtemp problems related to poor water flow at low revs, the severely retarded
spark timing which was used to provide a "smooth slow" idle & the excessive
fuel/oil mix being thrown through the engine just to keep it running at those
spark timings. (if they hadn't oiled up the plugs & stopped, they blew an
enormous cloud of blue smoke, when accelerated hard after long periods trolling)
(iii) In the early to mid 80s OMC started introducing it's proprietory "VRO"
oil injection system & advising other OMC motors to go to 100:1 mix. Both things
were a disaster. The system was a remote oil tank & a piggyback style
vacuum/pulse driven combined fuel/oil pump, then the "mixture" went through
various fuel lines to the carb(s). The idea was that the oil amount would be
directly controlled by the amount of fuel being pumped, which should have solved
problem (ii)(b) & probably would have, but OMC went much further they set the
combined fuel/oil pump so the oil ratio was varied throughout the fuel flow
range, from about 200-150:1 at "idle" to 100-50:1 at power. (hence VRO, Variable
Ratio Oiling)
(iv) OMC publicly & through their "factory trained" dealers claimed they had
solved problems (ii)(a,b,c,&d) they made no mention of (e) as if it were just
another manifestation of (a,b&c) but I suspect they knew better.
(v) Owners of OMC engines, particularly high HP started losing power heads
from catastrophic failure (bottom end) scuffed pistons, stuck rings etc. etc
(top end) OMC honoured their statutory warranty but that was all, engines beyond
that were told a variety of "excuses" by the "fact. trained dealers" ranging
from "bad fuel", use of "non OEM brand TC-W oil", "user abuse", "serviced by a
non OMC dealer", "the filter in the oil tank clogged from dirty oil", "the oil
line clamps were not OEM & allowed air in" or "have cracked the placky fittings,
even when they hadn't" etc. etc. In my "opinion" these defence lines could only
have been orchestrated/spruiked by OMC itself, because they were so consistent
from virtually every OMC dealer & are even still repeated by them in this NG.
(vi) In about 1988 OMC changed the oil injection rates on their VRO pumps to
ensure 50:1 at power. (but persisted with the very low oil at idle to stop plug
oiling & smoke). About this time they also changed the "recommendation" on tank
mixed engines back to 50:1. They "told" the OMC dealers & sent out service
bulletins in house but NEVER told the public, (the "official" line was that the
engines were rusting between rec. boater use because not enough oil residue was
left, they never admitted the truth, plain not enough oil) the OMC dealers
continued with a nice little earner repairing with OEM parts, all the pre 88
engines which were continuing to die because they were being used strickly in
accord with the operators manual (i.e. if tank mixed, 100:1 & if VRO a pump that
even when working as designed, didn't inject enough oil.)
There was no OMC re-call to fit the later model VRO pump nothing, just deception
from the OMC dealers when the owners power head exploded.
(vii) In the event the "new pump settings" didn't solve the problems & big OMC
engines continued to have low power head life, even driving the whole industry
to a new TC-W3 standard & re-test in 94-5 just to try & solve OMC's VRO
problems. They have changed the "settings" several times since then, trying to
make a bad design work, but they have never re-called existing motors to offer
the upgrade. (Even Bill Gates at least does that)
(viii) Had the OMC dealers had any real training in the subject they would have
or should have at least suspected the truth which "in my opinion" is that large
OMC, VRO equipped engines are in real trouble when trolled for long periods.
Cruisers, water skiers, rentals etc engines seem to last much better than those
used by fisherpersons, particularly those after pelagics, because;
(A) The cooling system; the waterpump is required to "pump" at
hugely varying shaft speeds, say 500-6500 so it is a compromise, partially
displacement at low revs & essentially centrifugal at high revs, trouble is long
before it's "worn out" the blades take a set & no longer operated properly in
"displacement mode" so at idle the tell tale shows water but there is not enough
flow/pressure.
(B) The ignition system; the OEMs have become obsessed with getting
their 2 strokes to idle like a 4 stroke, they have tried everything & settled
many years ago on running partially open butterflies to keep "flow" through the
motor but still get "slow smooth" idle by having the spark timing greatly
retarded. Any young hot rodder let alone an engineer, knows that running spark
ignition say 20-25 deg. ATDC will result in an almost instantaneous overheat, so
no other 2 strokes can get away with it, motor cycles, lawn mowers, hedgers,
chainsaws etc. etc. BUT the OB OEMs wrongly thought they don't have that problem
because they have an endless supply of cold water, which is sort of true; so
long as you can get the heat to it, i.e. across the ever larger diameter
pistons, across the piston, ringland/ring junction & then the ring/bore junction
so it can be carried away by the water flow. Big 2 strokes "trolled' for long
periods build up enormous internal heat, not in the block/water passages but the
piston/rings. This cooks oil rather than it being cleanly burnt & leaves
varnish/carbon deposits which get behind the rings (one of the hottest places) &
create blowby which just aggravates the situation & so on. They don't need the
less cooling they get at idle but because of their fueling/ignition they should
be getting & need more.
(C) The problems of (A) & (B) above are pretty much common to all 2
stroke OBs & most get away with it, Merc even recommeded lower temp thermostats
for engines that are "trolled" alot, at least they recognised the problem &
faced it full on but not OMC, instead their VRO actually causes engine failure
because when the engine is idling it "varies" the oil ration way down, they
don't even really know to what because it "varies" from pump to pump & engine to
engine but regardless there is very little oil getting injected at idle, which
stops the plugs fouling, stops the blue smoke & even reduces the amount of
unburnt oil to get "cooked" behind the rings but here is the problem;
(D) the pump is a long way & a big volume of fuel/oil mixture, from
the carb(s) it varies from engine to engine, but the bigger the engine, the
further from the pump & the more carbs, with bigger float bowls, etc. etc. the
more volume, so when they're idled for a long time the pump only supplies
virtually straight fuel (little oil), this completely replaces all the fuel
downstream of the pump with a very low oil mix.
(E) The engine is trolled maybe for hours, (you can do that now
because there is little oil to foul the plugs) the water pump isn't brand new,
not old or worn out just not brand new so water flow is down, the engine builds
up great internal heat, then the fisherperson pulls his/her lines & opens it up
to get home/go to another location/beat the storm whatever.
(F) There is no cloud of blue smoke because clever OMC have made
sure there isn't any oil there, the pistons are as hot as hell & suddenly the
engine is at full power & no oil; this equals even more heat then very quickly
scuffed pistons. (not recommended but if you doubt this, disconnect your fuel
line & see just how long the thing runs on the residual fuel in the system, then
imagine it, admittedly for a shorter time but even so, at full tilt, really
really hot, effectively without oil)
Just my "opinion" formed from the above but I say; the OMC, VRO
injection pump is a real problem running way too far behind what is really
needed/happening in the motor, dependent upon the type of use the engine sees.
Those "I'll look it up in my trusty OMC manual" dealers are never going
to admit this because they just don't have the training to know or it seems even
enough to ask the right questions. My "opinion" & advice is, go to a real
mechanic with real understanding & knowledge.
Now you blokes I'm ready for & wholly deserve my peer review; just be
gentle, try to keep it civil & be factual.
Best Regards:-)
Karen Smith.
On Sun, 21 Jun 1998 23:24:08 -0700, billgran <bill...@mail.n-jcenter.com>
wrote:
>Richard Eriksson wrote:
>>
>> Having an '85, 70 hp Evinrude motor bored and rebuilt. It has the
>> automatic VRO oil system and is used on a 17' boat with built in
>> 30 gallon gas tank. Several people have suggested disabling the
>> VRO pump and mixing the oil in the gas tank. On the other hand,
>> I have also been advised that Evinrude has redesigned the VRO pump
>> several times, the latest design is very reliable and I should include
>> a new style pump with the engine rebuild and use the VRO system.
>>
>> I'd like to use the VRO (if reliable) because of the built in gas
>> tank and conveinence. The boat is used for ocean fishing; trolling
>> for extended periods of time, with WOT used to beat the thunderstorms
>> on the way back to the dock.
>>
>> Recommendations? Thanks!
>>
>> Dick Eriksson
>
Richard Eriksson
K Smith wrote:
>
> Richard,
>
> It's good to see the OMC dealer team have now "come out" & declared
> their vested interest, very good & well done. (I might as well be hung for a
> sheep as a lamb)
>
> My "opinion" is stay right away from OMC "factory trained machanics"
Well, all I can say is: "Wow"! Thanks for the technical history of
the development of the VRO system. I have a question though. It has
been explained to me that the OMC VRO is a diaphram type pump with
one side pulling the gas and the other side of the diaphram pulling
oil. Assuming the failure mode is a rupture of the diaphram,
or overall failure of the pump to operate, wouldn't this also result
in no gas being supplied? No gas means the engine quits as soon as the
oiled gas in the carbs are used and no damage done due to lack of oil.
In any event, your post has caused me to re-think this issue. Maybe
the best thing to do is disable the VRO, mix the oil in the gas tank
and just put up with smoke and fouled plugs while trolling.
Dick Eriksson
Harry Krause
Richard Eriksson wrote:
>
> K Smith wrote:
> >
> > Richard,
> >
> > It's good to see the OMC dealer team have now "come out" & declared
> > their vested interest, very good & well done. (I might as well be hung for a
> > sheep as a lamb)
> >
> > My "opinion" is stay right away from OMC "factory trained machanics"
This is an absurd piece of advice. There is no way a good mechanic is going to
be able to handle the problems of modern outboard motors without attending
manufacturers' classes and getting certified in the specific skills needed.
We're not talking lawn mower engines here.
"Hey, Frankie, can you fix my FICHT fuel injection?"
"Dunno, Joe. Never seen one. You need any special tools? Hey...what does this
lil' chip right here do?"
bill...@orbiter.com
"
>
> Well, all I can say is: "Wow"! Thanks for the technical history of
> the development of the VRO system. I have a question though. It has
> been explained to me that the OMC VRO is a diaphram type pump with
> one side pulling the gas and the other side of the diaphram pulling
> oil. Assuming the failure mode is a rupture of the diaphram,
> or overall failure of the pump to operate, wouldn't this also result
> in no gas being supplied? No gas means the engine quits as soon as the
> oiled gas in the carbs are used and no damage done due to lack of oil.
> In any event, your post has caused me to re-think this issue. Maybe
> the best thing to do is disable the VRO, mix the oil in the gas tank
> and just put up with smoke and fouled plugs while trolling.
>
> Dick Eriksson
>
Dick, Anyone can type an opinion based on misinformation. Perhaps before you
think Karen is the last word on VRO systems, you might want to withold your
opinion until you read the facts from QUALIFIED, experienced, and trained
technicians who work with the system on a daily basis. Did anyone ask for
proof of Karen's background and training. Is she(he) afraid to give it out
for fear of lack of credibility? What kind of training and experience? Do you
honestly believe in today's business climate that a company can build
something that "doesn't work" for the last 15 years? With almost a million
engines from 40 thru 300 hp, don't you think there would be piles of broken
engines and landfills full of VRO pumps all over the country? People love bad
news and love to bitch and the ones that are happy say very little. I have a
feeling a lot more people have good luck with their engines and servicing
dealer than the few "loudmouths".
Bill Grannis
service manager
Bluewater Boats
A proud and successful OMC dealer with an ELITE rated service shop
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Dave Brown
K Smith wrote:
> It's good to see the OMC dealer team have now "come out" & declared
> their vested interest, very good & well done. (I might as well be hung for a
> sheep as a lamb)
Karen, you're ignorant rants have become tiresome. I have twice 'debated' points
with you only to be told I have resorted to personal attacks. I have re-read my
posts in the context given and claim innocence on all counts. It appears your first
line of defense is a good offense -- "no fair Dave, you're calling me names" rant
won't play with me or any other seasoned readers of this NG. That being said, I see
you hold no reservation calling into question my or my fellow proffesionals
credentials without any 'facts' other than your own opinion, which, as evidenced
your recent post, is sadly lacking in facts at all.
> My "opinion" is stay right away from OMC "factory trained machanics"
> Some are but, most are not "qualified" in any other manner than their OMC
> training, which is purely OMC parts replacement training, a bit like a kid doing
> all the McDonalds "training courses", hanging the achiever plaque on a
> restaurant wall & calling themselves a chef.
Mildly ammusing (and somehwat sad) that you perceive the entire industry in this
light. What makes it even more ironic is that the three OMC specialists who
participate in this NG have one thing in common -- a certificate from Hamburger U
that less than 5% of mechanics (of those who attend service school) receive as
recognition of their achievement in understanding, diagnosing, and repairing the
products they sell. I'm sure this will mean little to you (as you'll equate it to
mean we can flip burgers faster than the others), but those who know the depth of
undertsanding, years of experience, and knowledge this takes to achieve, recognise
this is a strong indicator that they've got something on the ball at a bare minimum.
To say that this achievement makes me a glorified parts replacer is something I take
personal offense to. You sir, are no better than what you accuse in others.
> If the guy you're dealing with ONLY has an OMC factory plaque hanging on
> his wall run away, you're about to be advised by someone who is not qualified as
> anything but an OMC parts re-fitter, re-marketer & big marker-upper of OMC
> spruiked product.
How ignorant, viscious, and mean spirited can one person be? You're setting new
limits with every word... At the very least you imply we have no minds of our own
to think with, at it's worst we're just a bunch of chimps who learned to hold a
hammer and are controlled by someone else. How unsettling this is given your
apparent gift of communcation.
> (iii) In the early to mid 80s OMC started introducing it's proprietory "VRO"
> oil injection system & advising other OMC motors to go to 100:1 mix. Both things
> were a disaster. The system was a remote oil tank & a piggyback style
> vacuum/pulse driven combined fuel/oil pump, then the "mixture" went through
> various fuel lines to the carb(s). The idea was that the oil amount would be
> directly controlled by the amount of fuel being pumped, which should have solved
> problem (ii)(b) & probably would have, but OMC went much further they set the
> combined fuel/oil pump so the oil ratio was varied throughout the fuel flow
> range, from about 200-150:1 at "idle" to 100-50:1 at power. (hence VRO, Variable
> Ratio Oiling)
To clarify your 'opinion', the move to 100:1 on smaller engines should not be
included in the same context as VRO lest it lead some to believe they are in someway
related -- they are not.
The first VRO pumps varied their oil from 50:1 (at WOT) to 150:1 at idle. The next
generation pumps reduced the mixture to 50:1 and 75:1 respectively. And to further
enlighten the readers to your understanding of the system (and judge your ability to
speak to the issue), the ratio is controlled by crankcase pressures (ie engine
load), not fuel volume as you suggest. Strike one.
> (iv) OMC publicly & through their "factory trained" dealers claimed they had
> solved problems (ii)(a,b,c,&d) they made no mention of (e) as if it were just
> another manifestation of (a,b&c) but I suspect they knew better.
During this time period, improvements to the pump, electronics, and protections were
passed along to the field. Every step of the way, mechanics attending service school
were informed of the problems, the corrections, and full disclosure (through school
and service bulletins) about the problems were given -- just like all the other
stuff going on with the engines (better ignition systems, carbs, alcohol resistant
hoses etc).Here's (e) grabbed from way below so review is in context:
> (E) The engine is trolled maybe for hours, (you can do that now
> because there is little oil to foul the plugs) the water pump isn't brand new,
> not old or worn out just not brand new so water flow is down, the engine builds
> up great internal heat, then the fisherperson pulls his/her lines & opens it up
> to get home/go to another location/beat the storm whatever.
That's simply absurd if you know how the cooling system actually works. For
starters, OMC has had trouble keeping their temperature UP because of OVERCOOLING.
The fact is, outboards idle best at 140 degrees (in itself not that high). Any
unusual temperature rise would be picked up by temperture sensors and relayed to the
driver (200 degrees in most cases). The minute that throttle is cracked, the
thermostats blow off their seats, the impeller blades fold flate against the hub and
water flows with the fury of a tornado. Worn impellor blades don't even enter the
equation because their not even touching the sides of the housing (acting now like a
recirculating pump, rather than a suction pump). I'm curious -- where does this
'great internal heat' hide in this process? At low speeds we have too much water and
the thermostats (when doing their job properly) take care of that nicely. If you're
therory is that they ran too hot, you'll be pleased as punch to learn that many
thermostat upgrades to these engines brought that temperture up even higher. The
result? A cleaner more consistent idle, no lean sneezing, better acceleration.
> (v) Owners of OMC engines, particularly high HP started losing power heads
> from catastrophic failure (bottom end) scuffed pistons, stuck rings etc. etc
> (top end) OMC honoured their statutory warranty but that was all, engines beyond
> that were told a variety of "excuses" by the "fact. trained dealers" ranging
> from "bad fuel", use of "non OEM brand TC-W oil", "user abuse", "serviced by a
> non OMC dealer", "the filter in the oil tank clogged from dirty oil", "the oil
> line clamps were not OEM & allowed air in" or "have cracked the placky fittings,
> even when they hadn't" etc. etc. In my "opinion" these defence lines could only
> have been orchestrated/spruiked by OMC itself, because they were so consistent
> from virtually every OMC dealer & are even still repeated by them in this NG.
I'll tell you this about OMC -- they have *always* gone well beyond their statutory
requirement when it comes to warranty. I can show you documents proving that OMC has
come good on parts a full four years out of warranty when OMC was aware of a defect.
OMC Cobra onwers were covered for over 7 years in some cases.
In the above example, it would seem that you are trying to say that all powerhead
failures are a result of an improperly working VRO system. Of course you'd be making
the same false assumption that many before you have made in an attempt to discredit
the VRO system. In reality, what happens is a powerhead fails, get's replaced and
then runs fine because the real culprit was corrected during the overhaul. It's just
too easy (and wrong) to blame the VRO for problems on and engine without supporting
evidence. For example, you speak of high HP engine failures resulting from bad
VRO's. Without siting case by case examples of known problems with particular
engines, I know a number of problems that were discussed at service school that
caused powerhead failures that had nothing to do with the VRO -- but to the
untrained schmuck in the field, the VRO was a mysterious and easy scapegoat.
To answer your charges: There are plenty of cases of oil filters plugging due to
mixing of different brands of oils (a thread that ran through hear some time ago) --
a process called 'gelling' and the good folks at NMMA will be happy to back this up.
It had nothing to do with the quaility of the oils, but everything to do with
additives being blended that were never intended to be together (ie brand X uses
additive X1, brand Y uses additive Y1, but X1 and Y1 don't like each other).
Everything was fine until someone decided to change oil brands in mid bucket.
With respect to use of non-OMC oil, I have yet to encounter a single incidence of
OMC even *asking* what oil was used, let alone denying a claim over it. In fact,
I'll use this opportunity to ask Bill & Carl if they have either -- guys?
Owner abuse? Please -- if you've heard some of the stories I have about what really
happens vs what the dealer gets told, well, let's just say some people will try
anything to displace fault. There'll be no questions about that in the future when
the Ficht computer reveals just what was occuring if/when the engine failed. I can
remember one case in particular where a customer had overheated his motor due to
weeds and decided the best thing was to get a new powerhead under warranty. He
figured that if he tilted the motor until the prop came out and let her rip at wide
open, that would do the trick. Well, it did something -- it blew the gearcase apart
and there was no shortage of people letting me know what he attempted to do.
> vi) In about 1988 OMC changed the oil injection rates on their VRO pumps to
> ensure 50:1 at power. (but persisted with the very low oil at idle to stop plug
> oiling & smoke).
They were *always* 50:1 at full power.
> About this time they also changed the "recommendation" on tank
> mixed engines back to 50:1. They "told" the OMC dealers & sent out service
> bulletins in house but NEVER told the public, (the "official" line was that the
> engines were rusting between rec. boater use because not enough oil residue was
> left, they never admitted the truth, plain not enough oil) the OMC dealers
> continued with a nice little earner repairing with OEM parts, all the pre 88
> engines which were continuing to die because they were being used strickly in
> accord with the operators manual (i.e. if tank mixed, 100:1 & if VRO a pump that
> even when working as designed, didn't inject enough oil.)
> There was no OMC re-call to fit the later model VRO pump nothing, just deception
> from the OMC dealers when the owners power head exploded.
Your statements border on criminal. There isn't a single manufacturer in the world
that could be held to your standard of care. By your logic, everytime a manufacturer
improves his product to make it better and more reliable, you expect a full and
total recall to get the customers upgraded. there is no such obligation legally or
morally to do so. They did exactly what they should have done (no different from car
dealers). They sent out service bulletins, updated the mechanics skills to spot and
repair potential problems, offered warranty assistance (out of warranty) to those
who deserved it and generally behaved in a professional manner. For my part,
everytime a bulletin came out, I *automatically* performed the update on all motors
entrusted to my care (often without the customer being aware this was being done of
his behalf). I wrote all the people who bought motors from me and informed them of
the recommmendation. Further, I always instruct anyone who asks for 100:1 at my
pumps if they're aware of the problem. To those who regularly run their motors they
will never see a problem running 100:1 in engines designed for their use. For those
who crank it up once per month, they may experience rust related problems and should
use 50:1. For those under heavy use (eg camps), they too should use 50:1 to ensure
long cylinder/ring life. Just out of curiosity Karen, do you actually know what OMC
did to allow their non-VRO engines to operate on a 100:1 mixture?
> (vii) In the event the "new pump settings" didn't solve the problems & big OMC
> engines continued to have low power head life, even driving the whole industry
> to a new TC-W3 standard & re-test in 94-5 just to try & solve OMC's VRO
> problems. They have changed the "settings" several times since then, trying to
> make a bad design work, but they have never re-called existing motors to offer
> the upgrade. (Even Bill Gates at least does that)
Again, it's absurd. There are *millions* of these pumps out there working on OMC
engines from 40hp to 300hp. What there are out there, are plenty of
misinformed/untrained 'mechanics' who try and blame the VRO for what ails the motor.
One of the reasons it was suggested by all three mechanics in the NG to take it to a
factory trained tech is so that items which can cause VRO failures are checked and
corrected, and the newest technolgy and warning systems are put in place to provide
the operator with better information. Furthermore, we will attend to all the other
little irritaing things that cause others to point finger at the VRO (eg
reciculation system, collant flow updates, exahust relief, timing and
synchronization changes etc). In short -- do all of the things a non-factory trained
mechanic can't do because he doesn't even know the fixes exist.
In a nutshell, here are a few common problems with VRO problems.
Improperly syncrhonized carbs causing the engine to 'lean spit' sending a large
chunk of PSI into a sensitively calibarted piece of equipment. Cost to repair? $10
for ther part and no damage to the powerhead because the fuel pump didn't operate
either. The fix? Proper set up by someone who knows what they're doing, coupled with
a special valve to protect the pump in case they don't.
Gelled oil plugging the filter (see explanation above). Cost to repair? Big bucks,
but an industry wide problem that was identified and corrected within a very short
time period (< 1 year).
No warning system. Initial pumps came with no indication something was wrong until
it was too late. By 1986, the first warning systems began to emerge and came as a
retrofit with new pumps. At the same time, pumps were refined and upgraded as
warranted. There was NO problem with the pumps themselves and I saw bushells of
pumps replaced under warranty that had nothing wrong with them. Personally, I can
recall only one instance where a VRO pump caused an engine failure because we've
always been able to detect and repair the real problem. Too many dealers (OMC and
Merc alike) are far too quick to blame something they don't understand.
> (A) The cooling system; the waterpump is required to "pump" at
> hugely varying shaft speeds, say 500-6500 so it is a compromise, partially
> displacement at low revs & essentially centrifugal at high revs, trouble is long
> before it's "worn out" the blades take a set & no longer operated properly in
> "displacement mode" so at idle the tell tale shows water but there is not enough
> flow/pressure.
Nonsense. Is this something you concocted yourself or are you being fed this manure
by someone else? Since you're making the charge -- what proof do you offer in
support? The truth is (once again), is that OMC pumps provide more than enough water
at low speeds and even a 'set' vane will provide ample water supply to meet the
engines needs. The way you make it sound, every ounce of water the pump puts out is
required to keep the engine cool and any loss of efficiency results in trouble.
Hogwash. Give the OMC engineers a bit of credit, will you?
> (B) The ignition system; the OEMs have become obsessed with getting
> their 2 strokes to idle like a 4 stroke, they have tried everything & settled
> many years ago on running partially open butterflies to keep "flow" through the
> motor but still get "slow smooth" idle by having the spark timing greatly
> retarded. Any young hot rodder let alone an engineer, knows that running spark
> ignition say 20-25 deg. ATDC will result in an almost instantaneous overheat, so
> no other 2 strokes can get away with it, motor cycles, lawn mowers, hedgers,
> chainsaws etc. etc. BUT the OB OEMs wrongly thought they don't have that problem
> because they have an endless supply of cold water, which is sort of true; so
> long as you can get the heat to it, i.e. across the ever larger diameter
> pistons, across the piston, ringland/ring junction & then the ring/bore junction
> so it can be carried away by the water flow. Big 2 strokes "trolled' for long
> periods build up enormous internal heat, not in the block/water passages but the
> piston/rings. This cooks oil rather than it being cleanly burnt & leaves
> varnish/carbon deposits which get behind the rings (one of the hottest places) &
> create blowby which just aggravates the situation & so on. They don't need the
> less cooling they get at idle but because of their fueling/ignition they should
> be getting & need more.
Wow, that's quite a mouthful and like the rest, speculative garbage. OMC has *never*
used partially open butterflies to adjust idle -- they usually use timing at a
whopping 4 degree ATDC (not even CLOSE to your speculative falshood of 20-25 deg). A
simple browse through any OMC manual will give you this spec and can only assume
that you're being purposely untruthful, or are being mislead by others who are. With
respect to cooling, one of the lesser known jobs of oil is to transfer heat from the
piston the to cylinder walls for proper cooling. Since there are those who believe
all oils are the same, this will mean little to them. To those who know otherwise,
this point is at least as important is its lubricating abilities. As for the
deposits left behind after combustion, that too is an oil quality issue that has
been dealt with (although I fully understand and accept not to your satisfaction) as
well as a fuel additive dilemma that has tested the limits of the outboards guys for
some time. Whether you like to beleive it or not, gas companies don't give a tinkers
toot what problems their fuels are causing in two strokes and oxygneated fuels are a
perfect example of this. The fact is, all that stuff they put in their to help your
car run better, usually ends up gumming the inside of two strokes and the engineers
in all camps are doing their best to counteract them.
> (C) The problems of (A) & (B) above are pretty much common to all 2
> stroke OBs & most get away with it, Merc even recommeded lower temp thermostats
> for engines that are "trolled" alot, at least they recognised the problem &
> faced it full on but not OMC, instead their VRO actually causes engine failure
> because when the engine is idling it "varies" the oil ration way down, they
> don't even really know to what because it "varies" from pump to pump & engine to
> engine but regardless there is very little oil getting injected at idle, which
> stops the plugs fouling, stops the blue smoke & even reduces the amount of
> unburnt oil to get "cooked" behind the rings but here is the problem;
They know *exactly* what their pumps are doing at every RPM and they also know a
thing or two about how much lubrication is required at a given RPM. Your assertion
is once again absurd and it is not my job to provide proof, as it is your assertion
to prove. I've said it before and I'll say it again, the use of a top quality oil
with the proper grade of fuel will result in an engine that burns clean.
> (D) the pump is a long way & a big volume of fuel/oil mixture, from
> the carb(s) it varies from engine to engine, but the bigger the engine, the
> further from the pump & the more carbs, with bigger float bowls, etc. etc. the
> more volume, so when they're idled for a long time the pump only supplies
> virtually straight fuel (little oil), this completely replaces all the fuel
> downstream of the pump with a very low oil mix.
Try this little experiment at home to give you some hard data to counter this claim.
Unplug the fuel line of any large OMC engine and crack to throttle to WOT. How long
does it go? 5 maybe 10 seconds before it runs out of fuel? Given that this test
includes quite a few more inches of gas line *before* the pump and you'll see pretty
quickly how little time it takes for an engine to receive the correct mixture. Now
try this -- hook up a can of gas mixed at 100:1 on a non-VRO engine and see if you
can get it to quit. You can't becasue 100:1 will work fine under these
circumstances. In other words, there isn't a spec of damage occurring to the engine
in the short interval. Couple this with tha fact that the crankcase is loaded with
puddled fuel and there's plenty of residual oil to do the required job.
> (F) There is no cloud of blue smoke because clever OMC have made
> sure there isn't any oil there, the pistons are as hot as hell & suddenly the
> engine is at full power & no oil; this equals even more heat then very quickly
> scuffed pistons. (not recommended but if you doubt this, disconnect your fuel
> line & see just how long the thing runs on the residual fuel in the system, then
> imagine it, admittedly for a shorter time but even so, at full tilt, really
> really hot, effectively without oil)
Been there, done that -- more uniformed speculation on your part. The funny thing,
is that you seem to be attaching a cause and effect relationship to the oil and blue
smoke. The truth is, OMC has had some problems dealing with fuel puddling in the
crankcase at low speeds and it is this fact that accounts for the smoking more than
the oil mix. You just need to see the trail of blue smoke coming from a 1985 140 hp
(with a 150:1 pump) to see this phenomenom (sp). One of the nifty things they teach
us at service school is how to address and fix this puddling problem (the fix lay in
the recirculation hoses and valves in the crankcase). Oops, I forgot, we were taught
how to flip hamburgers, not corrections to motors in the field.
> Just my "opinion" formed from the above but I say; the OMC, VRO
> injection pump is a real problem running way too far behind what is really
> needed/happening in the motor, dependent upon the type of use the engine sees.
Just my "opinion", but you've based your information on incorrect information from
the outset. Which begs the question, if you didn't gather this information from an
OMC tech (as they can't be trusted), what is your reliable source? Inquiring minds
want to know.
> Those "I'll look it up in my trusty OMC manual" dealers are never going
> to admit this because they just don't have the training to know or it seems even
> enough to ask the right questions. My "opinion" & advice is, go to a real
> mechanic with real understanding & knowledge.
>
> Now you blokes I'm ready for & wholly deserve my peer review; just be
> gentle, try to keep it civil & be factual.
How typical. You throw slander and untruths around like rice at a wedding, but we're
to adhere to different standard. I've spent far too much time on this and will
attempt ot bow out of this thread for a while while I get caught up on paperwork.
Have fun at my expense Karen, I won't be back to defend for a while -- that should
give you ample time to re-assure yourself that you've right and I';m just a burger
flippin' mechanic.
One last note -- up to this point you've deflected questions about your background
as being a non-issue. In my opinion, you've now crossed that line in this thread and
are morally required to provide the readers with something that gives credence to
your "opinion". I have laid my credentials out for people to judge, it's time you
did the same. Could it be, <gasp>, that you're really one of the uniformed Merc
techs who merely *think* they know the OMC stuff and can pass judgement accordingly?
I think you'll agree that if you can accuse me of bias becasue I'm a dealer, it's
only fair to know where you're coming from so you're bias' can be similarly held up
and judge/ridiculed as you have done with mine.
K Smith
Harry,
Well notwithstanding your snappy answer, my advice/"opinion" still
stands as regards Richard's question but very good point, you do appear to have
raised an important issue.
You might be aware that the OEMs or at least Brunswick & OMC are trying
very hard to make the new engines forever "captive" of the OEM dealers.
With longer warranties this is acceptable & it might be difficult for
you to see say 5 yrs but what then?
You seem to be a person who "trades" every couple of years so you might
believe this wont effect you but it will, because it'll be reflected in your
trade, unless you buy same again i.e. you're locked in.
The new DFI engines at this stage appear to be a big improvement on the
old 2 strokes but they're still petrol 2 strokes, the prices have gone up
dramatically & notwithstanding with some help from a NG friend, you were able to
side step the system (there will always be some "leakage") the average consumer
is going to be asked to pay a significant premium for these motors, then they
can ONLY have them serviced by the OEM dealer so any fuel saving will need to be
balanced against the extra predatory dealer pricing.
Here only certain limited "special" dealers are being allowed to sell
the new engines, (probably because they know the average is an unqualified
spruiker) they must install the new diagnostic equipment & in true Bill Gates
style undertake to stock a certain number of the new engines, before they can
qualify for their new "special" status. I've mentioned elswhere that the OEM
edict to these "special" dealers is "no discounting".
Again here, the set up cost to the dealer is high & I suspect the
"special" dealers are going to want this back in a hurry.
The time to know & think about these things is before you buy a new
super expensive Ficht or Optimax over say a Honda or other.
On the up side OMC wont be able to blame anyone else this time if it
goes the way the VRO did.
I don't really think it will though, because in my opinion the new DFI
technologies are good & regardless will put OBs into a price bracket that will
attract other competitors to the rec.boat market, clearly not for little boats
but 4 strokes, diesels etc. etc. start to look more viable.
As I said; very good point Harry. (you're not just a pretty face)
Karen Smith.
On Wed, 24 Jun 1998 11:24:58 GMT, Harry Krause <hkr...@gate-nospam.net> wrote:
>Richard Eriksson wrote:
>>
>> K Smith wrote:
>> >
>> > Richard,
>> >
>> > It's good to see the OMC dealer team have now "come out" & declared
>> > their vested interest, very good & well done. (I might as well be hung for a
>> > sheep as a lamb)
>> >
>> > My "opinion" is stay right away from OMC "factory trained machanics"
>
>
K Smith
Richard,
Yes a pump failure for any reason would be good, regrettably that isn't
what happens anymore than things "just happen".
Karen Smith.
On Wed, 24 Jun 1998 06:51:47 -0400, Richard Eriksson <re...@vptec.com> wrote:
>K Smith wrote:
>>
>> Richard,
>>
>> It's good to see the OMC dealer team have now "come out" & declared
>> their vested interest, very good & well done. (I might as well be hung for a
>> sheep as a lamb)
>>
>> My "opinion" is stay right away from OMC "factory trained machanics"
>
LaBomba182
>Subject: Re: Disable VRO pump?
>From: drif...@nospamwebrider.net.au (K Smith)
>Date: 6/24/98 7:06 PM US Eastern Standard Time
>Richard,
>
> Yes a pump failure for any reason would be good, regrettably that isn't
>what happens anymore than things "just happen".
>
>Karen Smith.
>
What? Capt. Bill
Dave Brown
bill...@orbiter.com wrote:
> Dick, Anyone can type an opinion based on misinformation. Perhaps before you
> think Karen is the last word on VRO systems, you might want to withold your
> opinion until you read the facts from QUALIFIED, experienced, and trained
> technicians who work with the system on a daily basis.
Amen.
> Did anyone ask for proof of Karen's background and training.
Yes, and was declined as not being relevent since he was only on a 'fact finding
mission'. :-)
> Is she(he) afraid to give it out for fear of lack of credibility?
Ya think????
> Do you honestly believe in today's business climate that a company can build
> something that "doesn't work" for the last 15 years? With almost a million
> engines from 40 thru 300 hp, don't you think there would be piles of broken
> engines and landfills full of VRO pumps all over the country? People love bad
> news and love to bitch and the ones that are happy say very little. I have a
> feeling a lot more people have good luck with their engines and servicing
> dealer than the few "loudmouths".
Even in this newsgroup (which tends to treat any announced problems as
worldwide), VRO has received little press. Food for thought.
> A proud and successful OMC dealer with an ELITE rated service shop
Did you get that rating at MacDonalds? <g>--
Dave Brown
Richard Eriksson wrote:
> > My "opinion" is stay right away from OMC "factory trained machanics"
>
> Well, all I can say is: "Wow"! Thanks for the technical history of
> the development of the VRO system.
Flawed as it was.
> I have a question though. It has
> been explained to me that the OMC VRO is a diaphram type pump with
> one side pulling the gas and the other side of the diaphram pulling
> oil. Assuming the failure mode is a rupture of the diaphram,
> or overall failure of the pump to operate, wouldn't this also result
> in no gas being supplied?
A quick VRO primer:
An OMC VRO pump uses both the positive and negative crancased pulses to drive
something called an air motor. Each pulse is directed through an appropriate valve
to suck on one side of the diaphram of the air motor, and push from the other.
Depending on the calibration springs in the pump and the frequency and strength of
the pulses (as determined by engine load), the diaphram eventually hits a release
pin that allows the diapram to return and start over. Connected to this diaphram
is a small stainless steel shaft that in turn is connected to both a fuel pump
diaphram and minute oil pump piston. On the oil side of the pump, the shaft has a
slot built in to creat 'lost motion' at lower speeds when the air motor is
realeased sooner in shorter strokes. This results in a leaner oil mixture. As the
pump winds up, the stroker become longer and oil flow is increased accordingly.
'No oil' detection is achieved comparing the tach reading with the oil pulses. If
it doesn't get the required count, it triggers the alarm.
In summary, there are three parts to a VRO pump -- an air motor, a fuel pump, and
and oil pump. Failure of the air or fuel pump results in the engine quitting
through lack of fuel and does not damage the engine in *any* way. Since the actual
oil pump is a piston with an o-ring around it, there are two things which can
cause it to fail - a broken o-ring (something I have never seen), or a broken
shaft (where the slot is cut for lost motion) -- something I have seen only once.
Even if the oil pump failed, the warning horn would sound immediately and prevent
damage (assuming the operator took the appropriate action).
The most common failure of the pump occurs when and improperly tuned/synchronized
engine 'lean spits' sending a high PSI charge of air into the air motor fracturing
the diaphram. The replacement part costs about $10 US and is easily fixed by
someone who knows what they are doing. The next most common failure is a ruptured
fuel pump diaphram and it's source is the same -- a pulse that drove the shaft too
hard and split the 'wagon wheel' support around the diaphram. Same part cost --
same easy diagnosis and repair.
So what did OMC do to beef up the system and protect it from failing? For
starters, they designed a valve very much like small reed valve that slams shut
when that sneeze is coming down the impulse. Next, they beefed up the diaphrams to
handle the shot should it get by.
> No gas means the engine quits as soon as the
> oiled gas in the carbs are used and no damage done due to lack of oil.
Bingo. :-)
> In any event, your post has caused me to re-think this issue. Maybe
> the best thing to do is disable the VRO, mix the oil in the gas tank
> and just put up with smoke and fouled plugs while trolling.
Perhaps my post will set you to thinking again then. The newest pump with the
proper valve installed in the pulse line will be every bit as reliable as running
50:1 without the oil mixing aggravation. Couple that with the possibility of
getting straight gas from a marina instead of mix and you can see you're opening
another can of worms.
bill...@orbiter.com
>
> You might be aware that the OEMs or at least Brunswick & OMC are trying
> very hard to make the new engines forever "captive" of the OEM dealers.
What makes you think they are making you captive??? Are the car makers with
their EPA mandated computer controlled systems making you captive? Independent
shops are doing better than ever due to trained techs in drivability and the
availability of test equipment.
> The new DFI engines at this stage appear to be a big improvement on the
> old 2 strokes but they're still petrol 2 strokes, the prices have gone up
> dramatically & notwithstanding with some help from a NG friend, you were able
to
> side step the system (there will always be some "leakage") the average
consumer
> is going to be asked to pay a significant premium for these motors, then they
> can ONLY have them serviced by the OEM dealer so any fuel saving will need to
be
> balanced against the extra predatory dealer pricing.
Servicing these engines are easier than ever since they are more reliable and
the electronics allow easy troubleshooting in the unlikely event of a
malfunction. The only people scared are the ones who don't understand, just
like a vast number of people are scared of computers.
>
> Here only certain limited "special" dealers are being allowed to sell
> the new engines, (probably because they know the average is an unqualified
> spruiker) they must install the new diagnostic equipment & in true Bill Gates
> style undertake to stock a certain number of the new engines, before they can
> qualify for their new "special" status.
Not true! No mimimums for the new engine orders, in fact, they are in such
demand that OMC and Merc cannot produce enough. The OMC is easily diagnosed
with an old 286 DOS laptop or better. Without a laptop, you can use the
warning system lites on the tach to blink out any error codes stored in the
engine. The manual and software is available to anyone. Merc uses their own
propietary software cartridge and a tester built by Owatonna Tool Co. Just as
when EFI stern drives came out, independent tool companies came out with
testers and software for the individual.
>
> The time to know & think about these things is before you buy a new
> super expensive Ficht or Optimax over say a Honda or other.
Have you priced a 500 pound 130 hp Honda yet?
Karen, you and Larry ought to compare notes, y'all sound the same.
Bill Grannis
service manager
Marcus G Bell
Dave Brown (da...@brownsmarina.on.ca) wrote:
> K Smith wrote:
Dave and Karen (and others),
This is completely off the subject, but it affects how you get your
point across to a large fraction of your audience. Many newsreaders
display in 80 column mode. When lines overshoot 80 characters, it is
at best painful to read. It is compounded when previous messages are
quoted, and it quickly becomes non-readable. As a favor to many of us,
please configure your software to limit your posts to 80 characters
per line. This might mean switching to courier font and making your
text window narrower, if you are using a "windoze" newsreader.
--
--
Marcus. ( be...@mail.med.upenn.edu )
Richard Eriksson
Dave Brown wrote:
>
> Richard Eriksson wrote:
>
> > > My "opinion" is stay right away from OMC "factory trained machanics"
> >
Hello Dave,
First, I would like to clarify that I did not make the above statement.
Karen did.
Second, thank you much for your explaination of how the VRO pump works.
The engine in question is being rebuilt and I was concerned (from all
I have heard) that the cause of the worn and scored cylinders was a
bad VRO. Turns out this was not the case. Upon investigation by the
mechanic (OMC factory trained, with plague on the wall, BTW), the
engine had experienced a serious overheating situation due to a bad
impeller. The previous owner had removed both poppet bypasses in the
thermostat housing in an attempt to get more cooling and continued to
try to run it.
The engine is back from the machine shop with cylinders bored;
being re-assembled today and back in the water tomorrow. As a
precaution we are installing a new VRO pump, of latest design as
part of the rebuild. The mechanic has instructed me as to the
break-in proceedure (going to use a temporary portable gas tank
to double up the oil mixture) and I will limit RPM's.
Thanks again,
Dick Eriksson
K Smith
Dave,
Well I knew I'd get the cane but that hurt, I know I've been
unnecessarily sarcastic etc. but genuinely; being a Karen I sometimes get
overly aggressive in technical discussions so as not to be dismissed for
reasons other than the quality of my reasoning. (although you blokes were
circling) I was on guard, no excuse, unreserved apology.
N.B I'm talking of engines used for long periods of idling/trolling, &
the engine damage (piston scuffing) when they are suddenly powered up after
same.
I'm interested in the technical facts of your response & wish to
comment, without rancour surely you have an interest in this because you must
have seen as many dead OMCs through scuffed pistons as anyone. I know owners
do.
My concerns were & remain related to the design concept of the VRO not the
execution & what I said about the engines related where the system (VRO,
Waterpump, Clean good fuel, good oil etc.) is operating as "designed" but the
"pattern of use" is long idle/troll followed by sudden powerup.
(i) Your defence & explanation of the VRO pump was not required. I never
said the pumps were prone to failure, what I did & do say is the design is
flawed because it reduces the oil too much at idle, (OMC must agree because
you say they keep increasing it) particularly long trolling type idle & then
takes too long for the now properly oil enriched fuel to reach the cylinders
furthest from the VRO pump.
(ii) Again your defence of the OMC water pump same applies, I conceded &
still do that sufficient water is pumped to stop the engine overheating at
idle trolling, the "heat" I was referring to was that in the piston/rings &
the ring/bore interface not the coolant temp so the alarms etc are not an
issue. I did point out that a perfectly normal deterioration in waterpump
performance (not enough to cause overheating in the normal sense) could be a
contributing factor, I tried to make it clear I was not talking pump failure.
(iii) Your comments on timing are curious, mine were not "speculative"
please check, I'm talking at slow idle, I think you're talking at the point
the throttle plates start re-opening. Alot of the NG have manuals so there is
no problem & YES the "requirement" is for somewhere between slightly before to
slightly after TDC at the time the throttle plate comes off it's stop but as
you know the spark has already been advanced a considerable distance by this
point (min another 10 deg. dependent on model etc) Again, at idle/troll I
maintain that the spark timing is very much retarded, much further than the 4
or so deg. before or after TDC specified in the manuals which is conditioned
"at the time the throttle plates start moving". (OMC even specify some
"special" tools to determine the point inthe advance when this happens) In
normal circumstances the engine is well above idle/trolling speeds at this
time.
(iv) No rancour, but you don't seem to be aware that the major problem with
2 strokes in general is getting rid of heat from the piston/rings, not the
bore, block or head (because more flow, bigger radiators or whatever will
normally cure this) it's the transfer of heat from the piston, through the
rings to the bore, that is the challenge, this is why 2 strokes are usually
limited to pistons of a modest bore diameter (an increase in bore greatly
increases the heat input area of the piston with only a small increase in the
circumfrance or the area of piston/rings to transfer the heat to the cooling
system) (please don't quote big ship type 2 strokes they're a different case)
(v) Regardless of our clearly divergent views on waterpumps & timing which
I used to explain why the engine's internal components are actually "hot"
after being idled/trolled for a long time, it seems you accept that the
engine, having been idled/trolled for a long time is completely fuelled by
fuel with the "idle" amount of oil, yes?
>Try this little experiment at home to give you some hard data to counter this claim.
>Unplug the fuel line of any large OMC engine and crack to throttle to WOT. How long
>does it go? 5 maybe 10 seconds before it runs out of fuel? Given that this test
>includes quite a few more inches of gas line *before* the pump and you'll see pretty
>quickly how little time it takes for an engine to receive the correct mixture.
>
Dave you know that an engine stops before it is completely dry of fuel in the
float chambers etc, indeed it'll stop as soom as the pump sees air, but even
so look at your watch for 10 seconds & imagine a big engine, on power
effectively without enough oil.
(vi) I say this,
(a) the big fuel systems (dependent on model) use a variety of pipes,
manifolds etc. to distribute the fuel to the carbs from the VRO pump. say the
engine uses 60 litres per hour on power ( about 150HP easy for maths) so it
uses 1 LPMin.
(b) now if completely dry (because the oil lean fuel has completely
replaced all fuel in every manner) I'm guessing the myriad of pipes, float
bowls etc would hold at least about 500-600 mls.
(c) This looks more like about 30 secs running before all the old, low
oil fuel is purged which I say is way too long to run a hot big engine without
or with low oil mix, further
(d) I wish to put that this is only an average time interval but the
actual time for each carb/cylinder varies. The consumption of 1 lpm is evenly
distributed betwen carbs but the new oil rich mix fuel isn't, it reaches some
carbs before it reaches others, in other words there is no way the new oil
rich fuel can pass/overtake the old oil lean fuel, so the carbs at the
beginning of the system actually run for less (maybe alot less) than the 30
secs I mention & the carbs at the end or furthest from the VRO pump run longer
(maybe much longer) than the 30 secs. Dave isn't this exactly how these
engines present after failure, isn't it usually (not always I know) the
cylinders which are on the longest fuel run that scuff?
Again let me repeat we're talking about engines that are idled/trolled
for long periods.
Again let me repeat, just my "opinion" which I genuinely hold & would
like to see it either properly dismissed or confirmed.
I have no connection with Merc. & would/will declare any conflicts of
interest.
Karen Smith.
On Wed, 24 Jun 1998 23:41:27 -0400, Dave Brown <da...@brownsmarina.on.ca>
wrote:
K Smith
Bill,
As I said "here" but I accept without reservation what you say on the
availability & service; thanks for the info.
Can you make any comment on the VRO system, I'll be obliged. It seems
in your flame to Jim you think it's a matter of luck;
-"I have a feeling a lot more people have good luck with their engines and
servicing dealer than the few "loudmouths"-
Surely you don't put it down to "good luck" when someones engine
doesn't fail.
Karen Smith.
Peter W. Meek
On 25 Jun 1998 06:46:11 GMT, be...@mail.med.upenn.edu (Marcus G Bell) wrote:
> As a favor to many of us,
>please configure your software to limit your posts to 80 characters
>per line.
In fact, make it 65 or so, to allow a nesting a few
quotes deep.
--
--Pete
pwm...@mail.msen.com (Peter W. Meek)
rec.boats caps at:
http://www.msen.com/~pwmeek/cap-main.html
Marcus G Bell
Peter W. Meek (pwm...@mail.msen.com) wrote:
> On 25 Jun 1998 06:46:11 GMT, be...@mail.med.upenn.edu (Marcus G Bell) wrote:
> > As a favor to many of us,
> >please configure your software to limit your posts to 80 characters
> >per line.
> In fact, make it 65 or so, to allow a nesting a few
> quotes deep.
Baby steps, Peter, baby steps. First the 80, so you don't have wor\
ds bleeding over
line boundaries at least. Once that is accomplished, then the extr\
a measure of
ensuring your words can be easily read when quoted in another's fo\
llow-up. My
right margin is somewhere around 69, and I often reformat noncompl\
iant posts
when quoting in the follow-up myself.
Decoding a post that wraps longer than 80 per line is like trying to
understand a bawling, coughing, hiccuping 6 year old describing how
his mean older brother pushed him off the dock.
R. Lee Wheeler
Dave Brown wrote:
>
> In summary, there are three parts to a VRO pump -- an air motor, a fuel pump, and
> and oil pump. Failure of the air or fuel pump results in the engine quitting
> through lack of fuel and does not damage the engine in *any* way. Since the actual
> oil pump is a piston with an o-ring around it, there are two things which can
> cause it to fail - a broken o-ring (something I have never seen), or a broken
> shaft (where the slot is cut for lost motion) -- something I have seen only once.
> Even if the oil pump failed, the warning horn would sound immediately and prevent
> damage (assuming the operator took the appropriate action).
Dave,
How does the VRO deal with oil viscosity shifts due to temperature? It
seems like it would pump less oil at colder temperatures.
I just bought a pontoon boat with a '90 Evinrude 3 cylinder. My marina
really groaned about it and told me that that moter is real prone to
seazing up. They weren't sure why, whether it is due to lean oil
mixture, lean fuel mixture, or improper channeling of cooling water
around the block.
The motor has some ignition problems and I am going to attempt to
resurect it this weekend. I'm considering going ahead and mixing oil
with the gas to augment the VRO and assure sufficient oiling. Short of
potentially fouling the plugs (cheap) can I really hurt anything else?
...Lee
bill...@orbiter.com
> I just bought a pontoon boat with a '90 Evinrude 3 cylinder. My marina
> really groaned about it and told me that that moter is real prone to
> seazing up. They weren't sure why, whether it is due to lean oil
> mixture, lean fuel mixture, or improper channeling of cooling water
> around the block.
I would have my doubts about them as a servicing dealer. There is a bulletin
about relocating the water tell tale outlet for the 70hp on pontoon boats due
to the aerated water flow and if the thermostat bleed hole gets plugged up.
Other than that, the 3 cylinder engine has been around since '68( 30 years )
and is still being produced. Look for a QUALIFIED OMC tech or call customer
service and ask for the ELITE rated dealership near you.
bill...@orbiter.com
>
> Can you make any comment on the VRO system, I'll be obliged. It seems
> in your flame to Jim you think it's a matter of luck;
>
> -"I have a feeling a lot more people have good luck with their engines and
> servicing dealer than the few "loudmouths"-
>
Perhaps I used the wrong word and you took it the wrong way. Maybe it should
read" ...a lot more people have good running engines and a good relationship
with their servicing dealer...."
I had a bunch to type about the VRO history but that Dave boy did a great job
and he is probably a lot better typist than I am. Reading your original post
on the VRO was a bit like watching the movie "Titanic"....historical fiction
!
In your post to Dave Brown about the lean oil mixtures at idle, I assume that
you no nothing of Yamaha systems. They run between 150 : 1 and 200 : 1 at
idle. They do have rusting problems in humid and salty conditions if the
engines are idled for a long time then shut down and left for a month or so.
Yammy recently changed their oil additive formulation to include more rust
prevention and anti-scuffing properties.
I deal in salt water environments and lots of my customers are die hard
offshore fisherman. They think nothing of 12 hour days of trolling and mad
dashes to different reefs or wrecks. Their VRO equipt engines run fine and
many have over 2000 hours on 10 year old engines. Our sheriff's boats either
idle all day waiting for violators or running flat out to catch someone. They
average about 800 hours a year. All these engines do not have piston
problems, VRO problems, or overheating problems. Most are serviced at the
required 100 hour intervals.
About VRO's. I have replaced a lot of them but not for "blowing powerheads".
Any new outboard rebuild gets a new pump just as any inboard engine rebuild
gets a new oil pump. Every rebuild gets the latest parts and updates. Most
VRO failures are for warning systems that make the horn sound though they are
still pumping fine. A few are replaced for leaks, just like any fuel pump,
and once in a while I've seen a crack in the plastic, probably from someone
overtorquing the mounting screws.
About factory trained mechanics. OMC has more different service schools than
any other manufacturer. They have 3 progessive schools from basic servicing
to advanced troubleshooting. There is a week long Ficht school. And there is
the Master Technician school for those who qualify. Like Dave said, it's less
than 5% even pass the tests. A Master Technician has to go back to school and
get retested every 2 years. His diploma will have an expiration date on it. I
was one of the first to receive this award in 1976 when it originated. OMC
teaches trouble shooting, not parts replacement. Each schooling level goes
deeper into the understanding of the various systems and how they interrelate
to each other. If someone says they are factory trained, ask to see the
diploma(s) and see which schools and when they were attended. (i.e., outboard
basic, intermediate, or advanced). Every good tech is proud of his or her
acheivements and should have the sheepskins on the wall or at least handy. If
you have any doubts about a dealer's competence, call customer service and
ask who is the ELITE dealer in your area. Those dealers have met the stiff
requirements concerning service related items and have to have a Master Tech
on staff.
If any other QUALIFIED tech wants to add something that I might have
overlooked. Have at it.
Bill Grannis
service manager
Bluewater Boats
Daytona FL
Peter W. Meek
On Thu, 25 Jun 1998 12:33:36 GMT, drif...@nospamwebrider.net.au (K Smith) wrote:
> N.B I'm talking of engines used for long periods of idling/trolling, &
>the engine damage (piston scuffing) when they are suddenly powered up after
>same.
By-the-by, Karin, on this sudden power-up scuffing, you
suggested interrupting the fuel flow to demonstrate
how long the low-oil fuel in the carbs would keep the motor
running. At 18 GPH (full power in my 175 Evinrude)
the gas in the carbs wouldn't last very long. It
might idle for a while, but at full power -- pffft!
I doubt that there is more than a few ounces of fuel
in all six carbs combined -- tiny bowls which are
almost entirely occupied by the floats. I calculate
fuel flow at about .64 oz per second full throttle.
If there was an ounce in each carb it would only
run ten seconds assuming those carbs would function
after the float levels dropped that far.
Don't forget, under normal (VRO running) conditions,
after five of those seconds, the gas in the carbs
is already half replaced with high-oil gas, and
getting higher by the microsecond. At that flow
rate, I'd expect pretty thorough mixing due to
turbulence in the bowls. This gas isn't just
drifting through there -- more like a fire hose.
K Smith
Dave & Bill,
Well again, as with the OEM oil, ample opportunity given to get the
facts correct so, now I'm afraid I'm even more worried about the competence
or lack of it as regards OEM dealers particularly the Dave & Bill team.
Regarding Dave & Bill's little testimonials, these people don't
even know how the engines they claim to be specialists in work.
As with each time Dave blasts me, with blatantly false or incorrect
technical info, I yield & even give him a hint as the correct answer & as
usual he doesn't come back, but this time his fellow OEM dealer Bill has
jumped in to back him up, well I say this absolutely confirms my views on
so called "factory tech. training" indeed my "opinion" is don't even get a
hamburger from this lot, they are your typical "I'll look it up in my
trusty OEM manual" types, guess what if it's not there THEY JUST DON'T KNOW
& even try to hide the fact by abusing me. Cheaky buggers.
Dave wrote,
>Wow, that's quite a mouthful and like the rest, speculative garbage. OMC has *never*
>>used partially open butterflies to adjust idle -- they usually use timing at a
>>whopping 4 degree ATDC (not even CLOSE to your speculative falshood of 20-25 deg). A
>>simple browse through any OMC manual will give you this spec and can only assume
>>that you're being purposely untruthful, or are being mislead by others who are.
(i) To-day much to the chagrin of my blokes I, myself, personally, me
(happy Dave) clocked up two OMC 80s vintage motors & found;
eng (A) had a total advance travel (armature plate) of 48 deg & a
placarded maximun total advance of 30 deg. BEFORE tdc (I checked & that was
the setting) so this engine when idling/trolling was running an ignition
timing of 18 deg. AFTER tdc.
eng (B) had a total advance travel of 55 deg & no placards as to
maximum advance, however the "manual" requires a setting of 4 deg. before
tdc at the time the throttle spindle commences to move, I checked this
motor & this gave the following outcomes, idle/troll ignition was at 19
deg. AFTER tdc, the top carb's throttle spindle commenced moving at 4 deg.
before tdc & the maximum advance available was 32 deg. before tdc.
THERE ARE THE FACTS.
They're not in your OEM manuals Dave & Bill because the OEM sees no
need to tell you (nothing to adjust or replace) & you lack the
knowledge/training or even the idle (no pun intended) curiosity to ask
Anyone can check what I've said & I hope many do; but if you don't
wish to actually clock it up to determine the exact numbers, just take your
OMC cowling off & have someone slowly increase the throttle level from dead
idle/troll (motor not running) & watch, you'll see that most of the early
travel is only advancing the spark timing, (the plate up under the
flywheel) usually by a system of rollers in slots, then finally the carbs
throttle plates are openned.
OMC use butterflies with cutouts, again easily verified, just take
the air silencer off virtually any OMC engine & look into a carb, past the
first butterfly (choke) to the second which you will see has a small hole
drilled somewhere (normal) & a section missing out of it's circumfrence,
hence "partially open butterflies".
These so called OEM "experts" with their scare tactics & abuse,
what a joke!
(ii) Had the dealer any knowledge at all they would know that running
severely retarded spark timing & 20 deg is "severe" will allow a docile
controllable idle in a big 2 stroke (the bigger the engine the more retard)
& allow the butterflies to be "partially open" at idle so allowing a good
air/fuel flow through the engine to give a stable idle but it will also
generate extreme heat.
Again if anyone has doubts, don't take my word for it, either do
it yourself or get assistance & run your older model (pre ECM) car just 10
deg after tdc, not only will it be "docile" you'll need to increase the
idle heaps just to keep it running (partially open the throttle plates), it
will overheat quickly & if you try to actually drive it around like that,
it will make the exhaust manifolds glow red.
(iii) It seems Dave admits to numerous changes in the VRO;
>>everytime a bulletin came out, I *automatically* performed the update on all motors
>>entrusted to my care (often without the customer being aware this was being done of
>>his behalf). even proud of
Well again I say the motors should have been re-called & still should,
because your "changes" to the VRO were not the fix for a poor design &
obviously your changes were of no help to those who had already lost their
engines & been OEM dealer told, bad fuel, wrong oil, user abuse, wrong
clamps & dirty oil $6000 please. (I bet the "customers not even being aware
bit" was a "tech. training" "suggestion")
Then Dave says;
By your logic, everytime a manufacturer
>>improves his product to make it better and more reliable, you expect a full and
>>total recall to get the customers upgraded. there is no such obligation legally or
>>morally to do so. They did exactly what they should have done (no different from car
>>dealers). They sent out service bulletins,
These things aren't $100 electric drills, some cost more than a
complete car & yes the auto industry does include "improvements" but this
is a serious design failure, i.e. even if everything is operating exactly
as it should an owner might have a catastrophic failure in a potentially
life dependent machine.
I accept I sound a bit aggressive again, sorry but I broke a nail
to-day, verifying something I already knew, because of the incompetence of
the OEM OMC Bill & Dave team.
Karen Smith.
Bob Hesse
Karen, it really does seem like time for you to lay out your
credentials???????
Bob
bill...@orbiter.com
>Karen Smith wrote:
>
> Regarding Dave & Bill's little testimonials, these people don't
> even know how the engines they claim to be specialists in work.
Since you have very little understanding and definately no engineering
experience, who are you to say ? Again, you do not give any credentials.
>
> (i) To-day much to the chagrin of my blokes I, myself, personally, me
> (happy Dave) clocked up two OMC 80s vintage motors & found;
> eng (A) had a total advance travel (armature plate) of 48 deg & a
> placarded maximun total advance of 30 deg. BEFORE tdc (I checked & that was
> the setting) so this engine when idling/trolling was running an ignition
> timing of 18 deg. AFTER tdc.
> eng (B) had a total advance travel of 55 deg & no placards as to
> maximum advance, however the "manual" requires a setting of 4 deg. before
> tdc at the time the throttle spindle commences to move, I checked this
> motor & this gave the following outcomes, idle/troll ignition was at 19
> deg. AFTER tdc, the top carb's throttle spindle commenced moving at 4 deg.
> before tdc & the maximum advance available was 32 deg. before tdc.
What difference does the advance or retard make if it is set to the
manufacturer's specifications? How did you determine the 19 ATDC timing since
the timing grid doesnt' read that high (low)? Did you use an automotive timing
advance lite that reads twice the spec on a 2 stroke engine? If you think they
are wrong, contact OMC Engineering department and tell them. The number is
708-689-6200.
Engine B may be a V4 since they have a cam pickup timing of 3-5 BTDC. Idle
timing is inconsequential since that is adjusted to set the idle speed, not
the carb openings. The throttle plates should be completely closed, not
partially open, the holes or annulus allow idle air to flow to the engine. A
90's vintage 200-225 idles throttle plates closed at 6 ATDC. A Yamaha at 7
ADTC and they adjust speed by cracking the plates. Large Mercs have similar
settings. So why do you prattle on about extremely retarded idle timing? Some
OMC's do set idle by "partially opening the throttles", do you know which
ones?
Obviously you are extremely delusional and believe that no one can make an
engine work except you. I have no more time to waste with your unfounded
dribble and outright untruths and I know a lot of the long term newgroup
folks feel the same way. Get a life.
Bill Grannis
service manager
-----== Posted via Deja News, The Leader in Internet Discussion ==-----
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K Smith
Peter,
I say this is "possibly", (only my "opinion") an explanation on why
the OMCs particularly the bigger ones suffered the loses during the 80's,
90s, such that OMC nearly went belly up.
I certainly don't say it's a proven fact, but IMHO it is a very
possible scenario, which OMC to my knowledge didn't pay enough attention to
because it would have called the VRO "design" into question rather than
just cliches in it's execution.
I formed my opinion in part because OMC have "fixed" nearly every
other explanation, increased the oil ratios several times, installed alarms
etc so we know oil is there for injection, valves to short circuit back
"spitting" (aggravated by the retarded spark timing), etc.etc. so what's
left given I must concede, that about the right amount of oil is in the
fuel when it leaves the VRO pump.
The engine damage is scuffed pistons, not consistent with just heat
damage, (there is no other damage at all, head gasket, discolourisation,
paint etc so the engine wasn't over temp) but low oil level. (my opinion
a combination of an engine at normal temp, but very hot piston & low or no
oil for a short time or the bearings would go to, they don't usually sieze
outright just lose compression)
I accept what you say about there not being much in the float bowls
but it's allot more than you think.
Like yesterday for the total advance movements, this is ACTUAL
MEASURED FACT & I hope any & many verify this for themselves, surely you
blokes have some curiosity left.
I'm picking through junked out parts, so I can't absolutely ID the
carb but I think it's from an 80s vintage 25HP Johnson, it still had it's
delivery tube from the pump attached so I;
(i) Clamped it level & filled it with fuel to the top of the hose (8mm
dia about 350mm long)
(ii) I removed the float drain plug & drained the contents into a jar
(iii) Using a kitchen medicine scale I measured the contents
So one carb off a small OMC engine, including it's hose holds well
over 40ml & slightly under 50ml of fuel. (about 17ml was in the hose the
rest was float bowl)
So if your 175 had the same sized carbs, it doesn't as you know &
used the same diam. hose, it doesn't as you know (just the hose going up to
10mm 3/8" increases the hose volume by 56%), it would hold a min of 240mls
& possibly up to 300mls
So on your own figures of 0.64 oz per sec it would run for 13.22
secs or 16.53 secs dependent upon 240mls or 300mls & that is if it had
the SAME plumbing/carbs as a 25HP motor.
The time involved is much longer than you imagine & for the carbs
at the end of the line even more so. (I Hope it isn't like the hose volume
although I suspect it is & these figures need to be increased by at least
56% to become 20.56 secs or 25.78 secs respectively.)
I hope you'll accept that if you don't accelerate away at
continuous Full throttle, just the usual quick big hit them back to cruise
the consumption goes way down & the time without enough oil goes up in the
same proportion so if you back off to say 2/3 throttle, but the engine
still has it's big carbs & hoses full of low oil fuel, is probably making
90-100 hp & your fuel consumption has dropped back to 0.36 oz per second so
the times have blown out to 36.55 secs or 45.83 secs respectively.
I hope you agree, scary bananas! Just watch the second hand on your
watch for that long, a very hot piston, at full or high tilt & low or maybe
no oil.
Peter please don't join the pack, stick with convincing me my
"opinion" is wrong, at least you accept the different fuels can't pass each
other & you're thinking about how long it might run in that condition; when
you have I'll admit it.
Karen Smith.
On Fri, 26 Jun 1998 12:09:54 GMT, pwm...@mail.msen.com (Peter W. Meek)
wrote:
>On Thu, 25 Jun 1998 12:33:36 GMT, drif...@nospamwebrider.net.au (K Smith) wrote:
>
>> N.B I'm talking of engines used for long periods of idling/trolling, &
>>the engine damage (piston scuffing) when they are suddenly powered up after
>>same.
>
Marcus G Bell
K Smith (drif...@nospamwebrider.net.au) wrote:
> My "opinion" is stay right away from OMC "factory trained
> machanics" Some are but, most are not "qualified" in any other
> manner than their OMC training, which is purely OMC parts
> replacement training, a bit like a kid doing all the McDonalds
> "training courses", hanging the achiever plaque on a restaurant wall
> & calling themselves a chef.
Karen,
Heving perused your screed, I can't help but flash a devilish grin
and remark to myself
**** BEWARE THE CHURCH OF THE LATTER DAY CONSPIRACY THEORISTS ****
OK, I have that out of my system now, and we can get down to
business. I'm not going to ask for your "credentials", but rather
address specific points themselves on their own merit. Like you, I
offer no credentials of my own, but it would seem that by your
criteria, providing no tracible evidence of knowledge of outboards
whatsoever puts one in better stead then having trained with the
pros.
> (i) Early days of 2 stroke OBs, tank mixed oil at from 25:1 to
> 50:1, but mostly 50:1, motors performed OK & lasted only OK but not
> too many catastrophic failures.
Try 8:1 to 16:1 before the mid 1950s, 16:1 in many "cheap" outboards
right into the '80s. 24:1 in the '50s and '60s, 50:1 in most from the
mid-60s on. But your points (ii)(a) through (d) stand nonetheless.
> (ii) The "problems with the early tank mixed engines were;
> (a) Excessive oil & fuel at idle which fouled plugs, (b)
> Inconsistent fuel/oil mix either by the owner or through settlement
> in the tank, (c) Difficult idle control because of (a) & (b),
> (d) What catastrophic failures did occur, they were mostly related
> to pre-ignition in larger HP engines, from too much oil which led
> to the fuel's octane being greatly reduced.
OK, sticking point on the last part of (d). Please describe the
antiknock index of straight oil, and what it would do to straight 87
(R+M)/2 gas at 50:1 and 24:1. Are you about to tell me that the
octane is reduced because of "dilution" as if oil burns like 100%
heptane?
> (iii) In the early to mid 80s OMC started introducing it's
> proprietory "VRO" oil injection system & advising other OMC motors
> to go to 100:1 mix. Both things were a disaster.
McCulloch went with 100:1 in the 1960s. Yamaha went with 100:1 right
alongside OMC in the '80s for non-injected outboards.
Also, OMC's VRO was but one system of oil injection. Yes, we hear of
a somewhat higher failure rate among the older VRO systems, though,
so some of the public seems to have been the unfortunate "beta
testers".
You harp on OMC's system a lot, but to be fair, you might consider
posting a survey of the many systems available. I'm fairly sure
Merc's system shares OMC's trait of injecting oil into the fuel
upstream of the carbs and injecting a lower ratio at idle, which you
would consider flawed by design. But how often does one carb of a
multicarb 2-stroke bite some dirt and take out a piston from
overlean condition, though? Therefore, any multi cylinder 2-stroke
engine which feeds and oils its cylinders from separate carbs must
be flawed by design. But all the major players do it.
> ... but OMC went much further they set the combined fuel/oil pump
> so the oil ratio was varied throughout the fuel flow range, from
> about 200-150:1 at "idle" to 100-50:1 at power. (hence VRO,
> Variable Ratio Oiling)
> (vi) In about 1988 OMC changed the oil injection rates on their
> VRO pumps to ensure 50:1 at power.
It always was 50:1 at WOT is my understanding. It was the idle mix
that was updated to 75:1 to protect the engine innards from extended
non-use after idling before shutdown.
> About this time they also changed the "recommendation" on tank
> mixed engines back to 50:1. They "told" the OMC dealers & sent out
> service bulletins in house but NEVER told the public,
Conspiracy, conspiracy! Well, OK, they could and should have handled
that better.
> but they have never re-called existing motors to offer the upgrade.
> (Even Bill Gates at least does that)
GUFFAW! If Bill Gates were running OMC, to get the "working version"
of the VRO unit, you'd have to BUY the upgrade, then upgrade your
transom, gas tank, remote box, bilge pump, windshield, anchor rode,
etc. Please, stop, you're killing me!
OK, this is off the point, but when you lob one up so close to the
net, it's pretty difficult to resist returning with a smash. Back to
the matter at hand.
> (A) The cooling system; the waterpump is required to "pump" at
> hugely varying shaft speeds, say 500-6500 so it is a compromise,
> partially displacement at low revs & essentially centrifugal at
> high revs, trouble is long before it's "worn out" the blades take a
> set & no longer operated properly in "displacement mode" so at idle
> the tell tale shows water but there is not enough flow/pressure.
Some pumps use this mixed function positive displacement/centrifugal
rubber impeller pump, some don't.
In the early 1940s, Mercury was the first to make use of the vane
pump which they called "Rotex". It was displacement-mode only. On
its big motors OMC had been using straight centrifugal, which had to
be waaayyyy oversized to pump at all at low speeds. On small motors,
centrifugal, as well as positive piston and eccentric/wobbler pumps,
were the order. When they got hold of the vane pump in the late
'40s, they gave it longer "finger" vanes and flattened its height,
then positioned the water inlet near the hub. At high speeds, the
vanes collapse inward and it operates truly as a centrifugal pump.
Johnson called it "Vari Volume" and Evinrude called it "Centrimatic"
(or vice versa).
The centrimatic is advantageous in that it can last a good long time
because the vane tips don't contact the pump volute at high speed.
On the other hand, the its large diameter means high tip velocities
in positive mode, and this can burn it out at lower speeds just the
same as any other vane pump. The large diameter also affected design
of the lower unit, forcing the lower unit casting to be wide at the
pump area. OMC cast the pump housing mount area integral to the
"splash plate" between the lower unit's anticavitation plate and
driveshaft housing.
(Karen probably knew some of this and will say I didn't need to
explain it to her, but let's remember that others may be paying
attention and could benefit.)
One way to tell whether your pump is "positive only" or "centrimatic"
is to look at the shape of the impeller. If each vane is as tall or
taller than its length extending from the hub, chances are it's
positive displacement only, because it's the wrong geometry for a
centrimatic. Corroborate this by noting the position of the water
inlet and outlet. For centrifugal mode, the inlet MUST be in near the
hub and the outlet MUST be out near the pump perimeter. If either
condition is not met, you therefore have a positive dislacement pump.
That's not a bad thing. The positive vane pump is thin in profile and
pumps water in proportion to RPM. Since it can deliver enough at high
RPM, you have decent assurance that it cools at idle too. Most OB
manufacturers use positive displacement on several, if not all, of
their models. Where I hear that all impeller pumps are fall into one
category, I am not so sure about any conclusions drawn from such a
generalization.
> (B) The ignition system; the OEMs have become obsessed with
> getting their 2 strokes to idle like a 4 stroke, they have tried
> everything & settled many years ago on running partially open
> butterflies to keep "flow" through the motor but still get "slow
> smooth" idle by having the spark timing greatly retarded.
You would prefer a motor that can't idle? And you say they "have
become obsessed"? We'll get back to that, as they became obsessed
with idle as recently as 90 years ago.
"Partially open butterflies to keep 'flow' through the motor" ain't
an outboard thing, a 2-stroke thing, or a 4-stroke thing. It's a gas
engine thing. They need air to mix with gas and spark to make that
"boom". Close the butterfly to effectively zero, and you reduce air
to zero and achieve a very smoothe idle indeed--"idle" as in "not
operating". Nobody should be surprised that the butterfly stays
partly open (or has a piece missing or "idle bypass" to accomplish
the same thing) in any gas motor.
OK, backpedal a bit. There's a reason why 2-strokes need a bit more
air than a 4-stroke to idle. Scavenging. That's right, getting the
exhaust out of the combustion chamber. In a 4-stroke's exhaust
stroke, you pump the cylinder almost empty of exhaust before you
try to suck in fresh air and fuel. In a 2-stroke, you allow the
exhaust to escape under its own expansion pressure, but once the
pressure is reduced to atmospheric, you are still left with the
cylinder full of exhaust. So, you force as much exhaust as you can
out with the fresh air and fuel entering elsewhere in the cylinder.
Now, say you reduce the incoming volume of fresh air by 50% by
throttling back. Now, you have a cylinder half full of exhaust, half
fresh air, all trying to mix during the compression stroke. On a
4-stroke, you might do that on purpose under load (EGR, exhaust gas
recirculation) to reduce combustion temperature and NOx production,
but at idle the EGR is zero. Back on the 2-stroke, this incomplete
scavenge/EGR effect is WORST when the throttle plate is closed. You
can see that there is some fraction of fresh air below which the
dang thing just isn't going to propagate a flame through the
combustion chamber during the power stroke. So, keep that throttle
open a bit, OK? Thankfully, the engineers took care of this for you,
and the butterfly can't close all the way.
This by the way is also part of the reason why the carbureted
2-stroke idle fuel/air mixture needs to be so rich. You need a
certain amount of fuel near the spark plug for the flame to
propagate, and it's hard to carry a flame through a cylinder full of
exhaust. The other problem is condensation and puddling in the
crankcase to which some of the idle mix is lost. Direct injection
puts the fuel near the spark plug and removes it from the crankcase,
allowing effective idle mixture to be leaner than at power.
Now, on to timing. Yep, spark timing has been used to control the
2-stroke outboard's speed since they were first mass marketed around
1910. Back then, most outboards had no throttle, and timing was your
ONLY speed adjustment. That timer lever could retard well after TDC
on those putt-putts.
So, with the very fancy addition of the throttle in the 1920s or so,
wouldn't you think adjustable timing would be unnecessary? Well, they
still need to retard a bit after TDC to slow down the idle with the
throttle closed as far as it can, and they certainly need to advance
it to well before TDC to get reasonble performance at high speed.
Show me a gas engine that doesn't adjust timing with RPM, and I'll
show you a low-tech cheapie or an engine that's tuned for a power band
that does not leave room for good idle. Of the 2-strokes with fixed
timing, chainsaws, weed-eaters, even a lot of dirt bikes all have
crappy idle, kick like a mule when you crank start them, and generally
snarl or spit unless running within some margin of their upper
range. Of the fixed timing 4-strokes, we have lawn mower and some
small tractor engines, not exactly the paragons of technology,
performance, cleanliness or efficiency, but there again generally
designed with a governor for 3600 RPM. Your modern car engine on the
other hand varies timing with any number of schemes to adjust for
engine speed and load and does an amazing job balancing economy and
performance.
Are you surprised that the outboard continues to use this very
effective system?
> Any young hot rodder let alone an engineer, knows that running
> spark ignition say 20-25 deg. ATDC will result in an almost
> instantaneous overheat, so no other 2 strokes can get away with it,
> motor cycles, lawn mowers, hedgers, chainsaws etc. etc. BUT the OB
> OEMs wrongly thought they don't have that problem because they have
> an endless supply of cold water, which is sort of true; so long as
> you can get the heat to it, i.e. across the ever larger diameter
> pistons, across the piston, ringland/ring junction & then the
> ring/bore junction so it can be carried away by the water flow.
Well, my recollection is that running your ignition retarded heats
up the EXHAUST much more than the engine itself. Karen even says so
herself in another post, let's find it:
Again if anyone has doubts, don't take my word for it, either do
it yourself or get assistance & run your older model (pre ECM)
car just 10 deg after tdc, not only will it be "docile" you'll
need to increase the idle heaps just to keep it running
(partially open the throttle plates), it will overheat quickly &
if you try to actually drive it around like that, it will make
the exhaust manifolds glow red.
OK, remember the car is a 4-stroke, so even when timing is severely
retarded the hot exhaust stays in the combustion chamber longer than
in a 2-stroke. Also remember that there is NO EGR at idle on the
car, but the 2-stroke enjoys a good amount of idle EGR and lower
combustion temps as a result. The outboard does not run retarded AT
POWER, so comparisons between outboards IDLING retarded and other
engines running retarded AT POWER are not likely of significant
value in this discussion.
Actually, all kinds of engines retard timing for idle. My VW Beetle
was designed to run around 5 deg ATDC at idle, for example. I
checked my manuals and see that many outboards indeed are configured
to idle around 6-12 deg ATDC, and that's not the setting for
"throttle pick-up" either but a true limit. Here's a twin cylinder
Merc that says to set max retard to around 17 deg ATDC for 600 RPM,
wow. So how about that, OMC does it, Merc does it, Suzuki does it,
VW did it. They must all be idiots. Ooops, I checked the manuals, so
I am now unqualified to render opinion. I take it back--I made it
all up :-)
Let's try again. I know from my very precise method of "staring at it
a long time and thinking about it a lot" that my 1966 Johnson 9.5
swings its stator plate about 60 degrees, which means I can probably
retard the ignition well beyond 20 deg ATDC if I want. I removed the
twist grip speed control linkage and literally could run that pup as
far retarded as the stator would move before the wires bumped into
the block casting. Below a certain retard, it seemed to not make much
difference to the speed, but it just shook more. I swear I could
read the part numbers on the flywheel while it idled that low, and
that blurb "set points 020". Hell of an idle on that motor; at high
speed it was a dog, but that's another issue.
Here's the point: it's much closer to 10 degrees ATDC where I set the
remote control to idle and shift, because a very slow yet regular
idle is still a shaky idle, and there is a slow setting above that
where idle is less shaky but trolls and shifts just great. That is to
say, just because the range of motion is there doesn't mean all of it
is used in practice.
So, after the explosion in the cylinder, where does the heat go? It
can be taken up by the expansion of the cylinder volume as the piston
goes down, which is good, as that's how your work gets done. At 10:1
compression ratio, up to 90% of the peak combustion temp will get
absorbed that way. Heat can also be absorbed by the water-cooled
cylinder head and walls, by the piston crown, and it can just go out
the exhaust ports for the hot exhaust to gasses expand the rest of
the way there.
The piston crown will reach a temperature at which the rate of heat
in from combustion is equal to the rate of heat out via conduction
to the cylinder wall and down into the air-cooled crankcase. The
same is true of the cylinder head and walls, by the way, balancing
conduction rate, heat removal into the cooling water, and heat
absorption from the combustion chamber.
Now, heat flows faster across a barrier when the temperature
differential is higher. The cylinder walls and pistons are designed
to move heat at a certain rate with a certain temperature
differential such that they don't melt. Now, where is the bigger
"boom" in the cylinder, idle or cruising speed? You guessed cruise,
didn't you? Good. So idle, with its smaller "boom", moves less heat
through the cylinders and pistons, ergo LOWER temperature
differential between water jacket and metal parts in the engine.
Let's retard timing to 55 degrees ATDC. What will heat up more, a
piston that experiences intense heat for 60 degrees of crank
revolution, or one that experience the same heat for 10 degrees? You
guessed the piston that is heated for more of the rotation, and
you're right. So, retarding timing from TDC to 55 deg ATDC will not
heat up the piston more, but the exhaust manifold will get a big
honking hit of heat as the combustion continues there. Please note
that we're not trying to get power from this engine.
Now let's try to get some power out out of this beast. Well, we're
running severely retarded, so at speed, we're getting less of a power
stroke per explosion because the peak pressure arrives well after TDC
instead of just before, so we get less torque transfered to the
crank. Gotta dump on more gas and make a much bigger explosion to get
the same power at the same RPM as we did when it was timed "the right
way". Did I say bigger explosion, but same power out? I did. So, same
cooling as before, bigger explosion, less heat absorbed by cylinder
volume expansion, more heat dumped into pistons and cylinders, WAY
more heat into exhaust. Well, yes, I think we'll over heat it. BUT
that was NOT idle.
> (C) The problems of (A) & (B) above are pretty much common to all 2
> stroke OBs & most get away with it, Merc even recommeded lower temp
> thermostats for engines that are "trolled" alot, at least they
> recognised the problem & faced it full on
Alternative explanation: when coolant flow rates are low, the
coolant can exist at several different temperatures in different
parts of the engine. This makes certain cylinders crap out sooner.
So, open the thermostat to make sure that the hottest cylinder which
operates well above the thermostat temp at idle will not exceed the
temp of death. This increased flow will also aid convection and
decrease temperature gradients.
With the cooler thermostat, Merc admitted they had a poorly designed
flow pattern, not that they needed a cooler idle. They could have run
the pump in bypass mode to rapidly circulate the water in the jacket
and even out the temperature. But that would be an extra pipe from
the block back down to the water pump. Screw that, lets just turn
down the heat instead.
Small engines idle their whole life without nearly the problems of a
big engine. Big engines do all kinds of crud to make up for some
pistons running hotter than others. Even vary the compression ratio by
design. (Some experienced Merc mechanics knew to lower the deflector
dome of the "direct charged" '70s 3-cylinder Mercs when they had the
engine open, even though it wasn't designed that way.)
So, it's time to look for other explanations for what one observes.
Oftentimes the seemingly plausible story can be matched with an
equally plausable but different story.
AAhh, I'm tired now.
K Smith
Bill,
Thanks for the abuse, now.
The timing thing so you accept that my figures are correct, a pity
you didn't check before you ran to Dave's aid but nonetheless now you say;
>
>What difference does the advance or retard make if it is set to the
>manufacturer's specifications? How did you determine the 19 ATDC timing since
>the timing grid doesnt' read that high (low)? Did you use an automotive timing
>advance lite that reads twice the spec on a 2 stroke engine? If you think they
>are wrong, contact OMC Engineering department and tell them. The number is
>708-689-6200.
>
As I said, I found tdc, scibed a mark on the ring gear & the
armature plate, then fully advanced the armature plate, scribed the ring
gear again, then fully retarded the armature plate & scribed again,
measured the distance between the scribe lines on the ring gear & worked
out the deg. from the circumference of the ring gear. The power heads were
junk, but still had the linkages attached so that was how the timing was
set when running.
Then you say:
>
>Engine B may be a V4 since they have a cam pickup timing of 3-5 BTDC. Idle
>timing is inconsequential since that is adjusted to set the idle speed, not
>the carb openings. The throttle plates should be completely closed, not
>partially open, the holes or annulus allow idle air to flow to the engine. A
>90's vintage 200-225 idles throttle plates closed at 6 ATDC. A Yamaha at 7
>ADTC and they adjust speed by cracking the plates. Large Mercs have similar
>settings. So why do you prattle on about extremely retarded idle timing? Some
>OMC's do set idle by "partially opening the throttles", do you know which
>ones?
>
Bill, exactly! the idle speed is controlled by spark timing rather
than throttle plate position, that's what I've been saying, not that there
is anything wrong at all with this.
The throttle plates are "bottomed" but they variously have cutouts,
(in addition to the normal bleed holes found in most throttle plates) so
it's not possible for the throttle body to be "closed" as with a 4 stroke
carb. (so even when the throttle plate is bottomed there is considerable
air/fuel still going to the engine so it will be running well above idle
revs)
There are simple reasons for this;
(i) Most OBs use reed type valves
(ii) When throttle plates that allow nearly complete throttling down are
used in large two strokes, the reed valves become inconsistent, (high
vacuum both sides of the reed) making a smooth slow idle difficult to
achieve/maintain.
(iii) As with (ii) when running high vacuum, the transfer ports can
transfer the wrong way, (the still exiting exhaust charge can go back down
the transfer port, diluting the incoming new charge) again making a smooth
slow idle difficult to achieve/maintain.
(iv) As a remedy (& a good one I say) to (i) & (ii) OMC (& yes others)
introduced the partially open throttle plates & then control idle speed
primarily with spark timing, this gives a slow smooth consistent idle & I
have no quarrel at all with the concept or it's execution. (it worked)
(v) About the only problem I can see is that engines so designed have a
tendency to spit, because the spark can be so retarded that it can actually
ignite the fresh incoming charge as it is transferred this is more an
idiosyncrasy than a problem & again I make no quarrel.
Bill the question of spark timing only came up in the context of me
trying to find a viable reason for piston scuffing in otherwise healthy
engines & I agree with Dave that a 2 stroke can run quite well on maybe
100:1 mix, BUT I did "suggest" that although the engine itself, (block,
heads, water jacket etc) is not "overheated" it was still possible the
piston could be very hot as a result of the long period of idle/trolling,
just the opposite to what you might think, my reasons are;
(i) At "normal" operating speeds, the spark is running somewhere 4 to
say 32 or so btdc & virtually all the "burn" is completed before the piston
even leaves TDC.
(ii) When running significantly retarded spark timing the "burn" is not
only commenced later, but it proceeds more slowly (less pressure) & in some
cases the "burn" can be still continuing when the exhaust port is
uncovered.
(iii) The piston, rather than seeing a sudden/sharp pressure rise
(450-600psi) at TDC it sees much less pressure rise because the piston is
retreating as the "burn" continues so it sees a constant combustion over a
much longer time. (more heat into the piston)
(iv) The inefficiency of running a much retarded spark is well known &
that "inefficiency" is manifested as lost heat, it can only go two places,
into the water jacket or out the exhaust, either way the piston sees it &
gets very hot, again not unusual & I offer no quarrel.
(v) I also raised a less than new waterpump impeller as another
aggravating factor, so although the engine isn't "overheating" it might
still be a bit hotter than normal after long trolling, again no big deal in
itself & I mentioned it as a "contributor" only
My "hypothesis" was that all the above factors could aggregate such
that when the motor was accelerated after a long troll, the engine
absolutely needs an oil rich (50:1) mix, I accept that 100:1 is adequate
for allot even most circumstances but not in this instance. (if not why
have OMC repeatedly changed the mix rates on the VRO)
I mused & still do that maybe the time lag between the VRO
injecting extra oil in response to the acceleration & it actually getting
into the cylinders MIGHT only might, be too long & be the reason scuffing
has occurred in some (ONLY SOME) motors.
If you're the owner of one of those "unlucky" motors it's not much
conciliation that "it only happens sometimes".
The rancour that has followed is unfortunate in the extreme but I'm
still astounded that OMC fact. trained techs were unaware of how "their"
brand controlled idle, & the rationale behind same.
Karen Smith.
On Sat, 27 Jun 1998 04:23:32 GMT, bill...@orbiter.com wrote:
>
K Smith
Marcus,
Thanks, but no conspiracy theory just a scuffed piston theory.
I was affronted when the OMC team advised that ONLY their techs had
the training to repair the VRO, which awakened me to the same old line
we've been fed for years that if a consumer loses an engine that was
serviced by other than an OEM tech, they virtually deserved it.
Thanks for at least looking at & confirming the retard at idle
thing, but don't get bogged down it was only one of the contributing
factors.
You bailed just as you got to the part I'm interested in, the fuel
flow/delay, your views on my hypothesis as regards the VRO I'll value, I'm
not just picking on OMC because of the Bill & Dave team but the VRO is
different to say Merc's.
(i) Merc's OEM manuals regularly "specify" 3 timings, the WOT the
throttle pickup & the idle, (say 18deg.atdc) whereas OMC don't (as Bill
points out they don't even mark the flywheel or put it in the manual
therefore Dave doesn't know)
(ii) this is a "potential" problem because if the throttle plates fail
to be "bottomed" even very slightly, for whatever reason the engine can
still be tuned in accord with the manual i.e. the engine can still be made
to idle as per specs rpm by further retarding the spark at idle, because
the "idle" adjustment is often just a spark timing adjustment.
(iii) This will further aggravate the "hot piston" if my "hypothesis" is
right.
(iv) Merc's oil inject is mostly closer to the carbs, there is also
sometimes an engine speed related interface with no "lag",
(v) But mainly Merc seem to be aware of the very scenario I allude to
because on some motors they spec. a low 120deg. thermostat for engines that
are trolled allot, why? if not to protect a hot piston.
Many manufacturers of 2 strokes have been doing much work on the
"scuffed piston" problem & the Porsche accelerated wear test has given
valuable insight, so people have been trying different ring materials,
anodised parts etc. etc.
These engines are too expensive to be left to luck.
Thanks for not abusing me.................too much:-)
Karen Smith.
On 27 Jun 1998 08:36:43 GMT, be...@mail.med.upenn.edu (Marcus G Bell)
wrote:
>K Smith (drif...@nospamwebrider.net.au) wrote:
Peter W. Meek
On Sat, 27 Jun 1998 05:08:11 GMT, drif...@nospamwebrider.net.au (K Smith) wrote:
<snipped measurement of a typical outboard carb/hose setup>
>
> So on your own figures of 0.64 oz per sec it would run for
<snip some preliminary estimates>>
> I hope you'll accept that if you don't accelerate away at
>continuous Full throttle, just the usual quick big hit them back to cruise
>the consumption goes way down & the time without enough oil goes up in the
>same proportion so if you back off to say 2/3 throttle, but the engine
>still has it's big carbs & hoses full of low oil fuel, is probably making
>90-100 hp & your fuel consumption has dropped back to 0.36 oz per second so
>the times have blown out to 36.55 secs or 45.83 secs respectively.
>
Your figures seem reasonable, and I agree that in my 175,
the amount of gas "in train" is likely to be higher than
I had guessed, particularly since I hadn't considered the
gasoline in the plumbing.
Yup, that would be a long time (30-45 seconds) with low
oil at high power. I've run my '91 175 at a no-wake
idle (1000-1100 rpm) alternated with WOT since I bought
it new (after break-in as specified in manual). I almost
never run at anything in between. I do tend to advance
the throttle slowly to avoid torque-steer surprises (maybe
a second or two at mid-throttle, correct the steering
slightly, then advance it all the way home). Since a lot
of my hours are commuting through a network of no-wake
and open water areas, I may make this transition on
an average of once every five or ten minutes. I may
make more hole shots per hour of engine time than
anyone except a teacher of beginner water-skiers.
I had the opportunity to be looking over my mechanic's
shoulder (as it were) while this motor was torn down
completely at about 500 hours (looking for an unrelated
problem). The cylinder walls and piston skirts were
glassy, with no evidence of galling or scuffing. It
had been run on OMC TC-W2 (and OMC 2+4) until TC-W3
came out, then OMC TC-W3. Also OMC Engine Tuner every
50 hours (by the meter on my FloScan). The rings would
slide in the grooves if the pistons were shaken. No
visible varnish or carbon anywhere in the motor. I
also had my lower unit serviced and water pump inspected
every 50 hours, and a water pump kit every 200 hours
(whether it needed it or not).
At any rate, very hard use combined with (likely)
above average service and "feeding". I depended
on the VRO except for the break in period where
extra oil was added to the gas directly.
<re Karens's better estimate of 30-45 second low oil times>
> I hope you agree, scary bananas! Just watch the second hand on your
>watch for that long, a very hot piston, at full or high tilt & low or maybe
>no oil.
Yes, that would be a long time with low-% oil. Because of
the conditions described above, I have to assume that by
themselves, these episodes of low oil acceleration do
not, *by themselves*, cause piston scuffing. It evidently
requires some aggravating factor. Maybe weakening water
pump performance, maybe slightly sticky rings, maybe
slight differences in oil performance, maybe something
which has never yet been discussed in rec.boats (although
it is hard to imagine what that might be). This discussion
should not be over yet. It would be very worthwhile to
try to isolate exactly what *does* aggravate these
low oil accelerations and cause piston scuffing. I'd
like to know what things to avoid and what parts of
my (expensive) service regimen I could ease off on.
bill...@orbiter.com
In article <35962792...@news.webrider.net.au>,
drif...@nospamwebrider.net.au (K Smith) wrote:
> I was affronted when the OMC team advised that ONLY their techs had
> the training to repair the VRO, which awakened me to the same old line
> we've been fed for years that if a consumer loses an engine that was
> serviced by other than an OEM tech, they virtually deserved it.
The repair kits available for the VRO are only the fuel pump parts. On the
latest pump you can get the oil pump portion as an assembly. The repair
procedures are in the service manuals (God forbid, someone may read the
manual) and if the procedures are followed, any mechanically oriented person
can repair it. All the marine companies want the customer to have the engine
serviced by their dealers and by trained techs. Thats understandable.
Independent mechanics cannot perform warranty repairs(except in special
instances) but there are many that study service manuals and genuinely do a
good job servicing engines. A lot of consumers do good repairs also, that's
why service manuals are available.
>
> (i) Merc's OEM manuals regularly "specify" 3 timings, the WOT the
> throttle pickup & the idle, (say 18deg.atdc) whereas OMC don't (as Bill
> points out they don't even mark the flywheel or put it in the manual
> therefore Dave doesn't know)
Most later engines have an ATDC grid but not to the 19 degrees as you
mentioned in a previous post. You talked about '80s vintage engines but be
advised that linkage, adjustments, and specs change with different models and
years. The manuals do list the idle timing as a starting point to set idle
speed. If the engine is operating correctly, the idle timing will be within a
couple of degrees of the spec.
> (iv) Merc's oil inject is mostly closer to the carbs, there is also
> sometimes an engine speed related interface with no "lag",
> (v) But mainly Merc seem to be aware of the very scenario I allude to...
Do you realize that all EFI motors from Merc and Yamaha have fuel resevoirs
called vapor separators that hold more fuel than carbs and that the oil pump
injects the lube into these large chambers? Therefore there is a lot longer
lag time with fuel injection systems than with carbureted systems.
Karen, Your last post was more civil (there was a dig at Dave Brown, but he
is tough) and had less vitriolic wording. Thanks, a rational discussion of
issues is what this newsgroup is about.
WANATEE OR
with the exception of the dfi and ficht motors, they have a multi point oil
injection system with no lag time as with the carburated oil injected yamahas.
David.
K Smith
Bill,
This unfortunate thread got underway because Dave posted;
>Go with the new pump kit (and horn). Make sure the mechanics are factory
>trained OMC guys doing the work.
Then you backed him up with;
>The "mechanics" that you mentioned are probably not currently factory
>trained and do not understand the system. The VRO came out in 1984, 14
>years ago, and more than 1 million engines from 40 thru 300 horsepower
>are equipt with oil injection. It is the only system that has a no-oil
>flow warning, other engines can "fry" without any indication from the
>oil system.
>Install the new VRO and update the tank filter, hose, bulb, and clamps.
>A QUALIFIED tech will know what to do. You will also get a 1 year parts
>and labor warranty. If you install the new warning horn also, you will
>have the same reliability as a new engine.
>Bill Grannis
>service manager
It now seems that you are changing your previous position to a more
reasoned/factual one & sincerely thanks; by now saying;
>>
>>The repair kits available for the VRO are only the fuel pump parts. On the
>>latest pump you can get the oil pump portion as an assembly. The repair
>>procedures are in the service manuals (God forbid, someone may read the
>>manual) and if the procedures are followed, any mechanically oriented person
>>can repair it. All the marine companies want the customer to have the engine
>>serviced by their dealers and by trained techs. Thats understandable.
>>Independent mechanics cannot perform warranty repairs(except in special
>>instances) but there are many that study service manuals and genuinely do a
>>good job servicing engines. A lot of consumers do good repairs also, that's
>>why service manuals are available.
I reacted, maybe even over-reacted, regarding your last post, I've
already apoligised & do so again if needed.
Now back to the issue that has come up, you say;
>>
>>Most later engines have an ATDC grid but not to the 19 degrees as you
>>mentioned in a previous post. You talked about '80s vintage engines but be
>>advised that linkage, adjustments, and specs change with different models and
>>years. The manuals do list the idle timing as a starting point to set idle
>>speed. If the engine is operating correctly, the idle timing will be within a
>>couple of degrees of the spec.
>>
Might I suggest a possible scenario;
(i) An owner or inexperienced friend tries to "tune" a motor
themselves, tinkers with most everything,
(ii) In their "experiments" they try to get it to idle by adjusting the
synchronisation.
(iii) The real problem is a throttle plate that doesn't quite bottom when
closed, maybe just one on a big engine. (the reason can be anything, bent
shaft, piece of crud, etc. etc)
(iv) Eventually the owner takes it to a proper tech, but of course
doesn't say "we've been tinkering with this for three weeks & can't get it
to idle".
(v) The proper tech absolutely follows the OMC manual, variously but
mostly, sets "pickup timing" (finds a problem synchronisation & says ah ha
this is the problem) starts engine & checks WOT timing with a light, no
problem set,
(vi) Now the tech does a final idle speed check & adjusts the idle to
spec. Here is my "potential" problem if there is an "even slightly" more
than new open throttle plate somewhere, which has gone un-noticed the tech
can unwittingly set the spark very much retarded at idle, he needs to just
to achieve the idle as specified with a very slightly stuck open plate.
(certainly much further than the OEM ever intended) Of itself not a big
problem but maybe a problem if the engine is trolled allot really heating
the piston up.
(vii) The absence of an OEM spec. as to the max. spark retard at the
spec.idle speed, which the tech. can actually have marks to check is a
"potential" which will never have any effect in normal use, but "might" in
the long troll then big hit case being discussed.
Again as I said to Marcus, the timing at idle/troll isn't a huge
problem on it's own just a contributor, which if recognised as such I feel
could lead to a better fix for users of older motors.
But let me be clear I have a problem with "some" of Dave's "advice"
(N.B. only some & only the advice, he is OK on the factual stuff he pulls
from the manual provided he actually bothers to look it up)
You lot have got me being called "princess" 30 yrs late but
anyway; thanks!
Karen Smith.
bill...@orbiter.com
In article <199806282103...@ladder03.news.aol.com>,
The EFI Yamahas and EFI Mercs do not use multi-point oil injection. They mix
the oil in the vapor separator before it is pumped to the fuel rails then to
the injectors. There is a "long" lag time.
bill...@orbiter.com
In article <3596e46a...@news.webrider.net.au>,
drif...@nospamwebrider.net.au (K Smith) wrote:
>
> Bill,
>
> This unfortunate thread got underway because Dave posted;
>
> >Go with the new pump kit (and horn). Make sure the mechanics are factory
> >trained OMC guys doing the work.
>
> Then you backed him up with;
>
> >The "mechanics" that you mentioned are probably not currently factory
> >trained and do not understand the system.
I recommend that customers use a factory trained mechanic whenever possible.
If your needed work and one mech was trained and one wasn't and you did not
know either one, which would you choose?
>
> Might I suggest a possible scenario;
>
> (i) An owner or inexperienced friend tries to "tune" a motor
> themselves, tinkers with most everything,
> (ii) In their "experiments" they try to get it to idle by adjusting the
> synchronisation.
> (iii) The real problem is a throttle plate that doesn't quite bottom when
> closed, maybe just one on a big engine. (the reason can be anything, bent
> shaft, piece of crud, etc. etc)
> (iv) Eventually the owner takes it to a proper tech, but of course
> doesn't say "we've been tinkering with this for three weeks & can't get it
> to idle".
> (v) The proper tech absolutely follows the OMC manual, variously but
> mostly, sets "pickup timing" (finds a problem synchronisation & says ah ha
> this is the problem) starts engine & checks WOT timing with a light, no
> problem set,
> (vi) Now the tech does a final idle speed check & adjusts the idle to
> spec. Here is my "potential" problem if there is an "even slightly" more
> than new open throttle plate somewhere, which has gone un-noticed the tech
> can unwittingly set the spark very much retarded at idle, he needs to just
> to achieve the idle as specified with a very slightly stuck open plate.
You are grasping at straws. If a mech followed the manual as you said, one of
te first things is to acertain that the plates are completely closed. If one
is a bit open, that (those) cylinder(s) run lean and pop or backfire at idle.
>
> But let me be clear I have a problem with "some" of Dave's "advice"
> (N.B. only some & only the advice, he is OK on the factual stuff he pulls
> from the manual provided he actually bothers to look it up)
Dave knows his stuff and I think an apology is in order to him. My post was
to "kid" him about a typo. He probably forgot more about OMC outboards than
you will ever learn. I have never met the gentlemen, but from reading his
posts for the last few years, he is one of those rare dealers that care about
his customers and is willing to spend some of his hard earned free time,
helping people out in this newsgroup. He spends 15 hour days in a very short
season trying to make a living. Running a marina is 10 times the work of
running a dealership on land.
>
> You lot have got me being called "princess" 30 yrs late but
> anyway; thanks!
>
> Karen Smith.
I was not the one who started calling you the fact "princess".
Del Cecchi
Here in Minnesota we fish for a fish called a Walleye. One of the most
popular methods to fish for Walleye is to use live bait, such as a leech
or a minnow, and fish nearly vertically below the boat while trolling as
slowly as possible. Many people even "backtroll", running the motor in
reverse and backing the boat slowly into the wind so as to obtain the
best manuverability and slowest speed while working their "rigs" around
rock piles and submerged islands.
If running a motor in such a fashion caused excessive heat build up in
the pistons, there would be an epidemic in Minnesota. This does not
seem to be the case.
The idea that running at an idle, using only a very tiny amount of fuel,
would cause the pistons to heat up more than running at wot seems far
fetched to me. The amount of heat generated at WOT is so much greater,
and the conduction path to the cylinder walls via oil or piston rings is
the same.
I would believe that uneven water flow could cause a cylinder or two of
a v6 to run hot when the flow is low at idle.
Do you have any other evidence for your theory besides idiopathic
scuffed pistons?
Del Cecchi
Rochester, MN
K Smith wrote:
>
> Bill,
>
> I really think you're still missing the point;
>
> (i) There is virtually no idle speed control from the throttle plates
> it's almost entirely from the spark timing. I'm not suggesting a stuck
> "open" plate that would be noticeable, just enough say from crud on one
> plate or normal wear on all shafts/plates, to make the engine idle high,
> say 900 instead of 700.
>
> (ii) This is seen as just the "differences" between engines & is
> routinely adjusted out with the "idle speed screw", which is actually a
> maximum SPARK TIMING retard screw, which can leave the engine overly
> retarded at idle
>
> (iii) As you have pointed out & it is obvious from yours & other dealer
> replies there is no or little knowledge of what the engine's timing is at
> idle. (were there marks available as on some, only some Mercs, I bet even
> you would be surprised at the variance, from brand new engine to brand new
> engine)
>
> (iv) OMC have gone chasing this scuffed piston "sometimes for no
> apparent reason" problem looking almost exclusively at the VRO pump oil
> injection rate, changing/increasing the rate such that they again had a
> plug fouling problem, so they increased the thermo temp in an attempt to
> burn it off etc.etc.
>
> (v) All I'm saying is if part of the secifications was a max spark
> retard at idle then that would eliminate one of the possible only possible
> contributors to the problem. (high piston temp by idling for long periods
> on a too much retarded spark)
>
> (vi) Again I wish to stress, I'm only talking motors that are dead
> idled/trolled for very long continuous periods. (usage like that Peter
> described earlier at 1100 rpm for a long time maybe but not hours
> continuously, would not be the dead idle/troll which is what fishermen with
> big motors on small boats need just to get down to "their" chosen trolling
> speed, then they sometimes stay there for literally hours)
>
> Karen Smith.
>
> On Mon, 29 Jun 1998 12:47:10 GMT, bill...@orbiter.com wrote:
>
>
K Smith
Bill,
Karen Smith.
On Mon, 29 Jun 1998 12:47:10 GMT, bill...@orbiter.com wrote:
>In article <3596e46a...@news.webrider.net.au>,
> drif...@nospamwebrider.net.au (K Smith) wrote:
>>
>> Bill,
>>
>> This unfortunate thread got underway because Dave posted;
>>
>> >Go with the new pump kit (and horn). Make sure the mechanics are factory
>> >trained OMC guys doing the work.
>>
>> Then you backed him up with;
>>
>> >The "mechanics" that you mentioned are probably not currently factory
>> >trained and do not understand the system.
>
>I recommend that customers use a factory trained mechanic whenever possible.
>If your needed work and one mech was trained and one wasn't and you did not
>know either one, which would you choose?
>
>>
>
>> Might I suggest a possible scenario;
>>
>> (i) An owner or inexperienced friend tries to "tune" a motor
>> themselves, tinkers with most everything,
>> (ii) In their "experiments" they try to get it to idle by adjusting the
>> synchronisation.
>> (iii) The real problem is a throttle plate that doesn't quite bottom when
>> closed, maybe just one on a big engine. (the reason can be anything, bent
>> shaft, piece of crud, etc. etc)
>> (iv) Eventually the owner takes it to a proper tech, but of course
>> doesn't say "we've been tinkering with this for three weeks & can't get it
>> to idle".
>> (v) The proper tech absolutely follows the OMC manual, variously but
>> mostly, sets "pickup timing" (finds a problem synchronisation & says ah ha
>> this is the problem) starts engine & checks WOT timing with a light, no
>> problem set,
>> (vi) Now the tech does a final idle speed check & adjusts the idle to
>> spec. Here is my "potential" problem if there is an "even slightly" more
>> than new open throttle plate somewhere, which has gone un-noticed the tech
>> can unwittingly set the spark very much retarded at idle, he needs to just
>> to achieve the idle as specified with a very slightly stuck open plate.
>
>You are grasping at straws. If a mech followed the manual as you said, one of
>te first things is to acertain that the plates are completely closed. If one
>is a bit open, that (those) cylinder(s) run lean and pop or backfire at idle.
>
>
>>
>> But let me be clear I have a problem with "some" of Dave's "advice"
>> (N.B. only some & only the advice, he is OK on the factual stuff he pulls
>> from the manual provided he actually bothers to look it up)
>
>Dave knows his stuff and I think an apology is in order to him. My post was
>to "kid" him about a typo. He probably forgot more about OMC outboards than
>you will ever learn. I have never met the gentlemen, but from reading his
>posts for the last few years, he is one of those rare dealers that care about
>his customers and is willing to spend some of his hard earned free time,
>helping people out in this newsgroup. He spends 15 hour days in a very short
>season trying to make a living. Running a marina is 10 times the work of
>running a dealership on land.
>
>>
>> You lot have got me being called "princess" 30 yrs late but
>> anyway; thanks!
>>
>> Karen Smith.
>
>
>I was not the one who started calling you the fact "princess".
>
William Robison
> > (vi) Now the tech does a final idle speed check & adjusts the idle to
> > spec. Here is my "potential" problem if there is an "even slightly" more
> > than new open throttle plate somewhere, which has gone un-noticed the tech
> > can unwittingly set the spark very much retarded at idle, he needs to just
> > to achieve the idle as specified with a very slightly stuck open plate.
>
> te first things is to acertain that the plates are completely closed. If one
> is a bit open, that (those) cylinder(s) run lean and pop or backfire at idle.
>
I'd be willing to bet that both Bill Grannis & Dave Brown
re-synchronize
the carburetors on virtually every motor as a fist step.
It's the first step in the procedure as no other adjustments are
effective
until throttle synch, choke synch, and throttle pickup are correct.
(I'd say 'grasping at straws' is generous)
regards
-Willy
bill...@orbiter.com
>
> I'd be willing to bet that both Bill Grannis & Dave Brown
> re-synchronize
> the carburetors on virtually every motor as a fist step.
> It's the first step in the procedure as no other adjustments are
> effective
> until throttle synch, choke synch, and throttle pickup are correct.
> -Willy
>
You are so right. I can't speak for my Canadian cousin since we've never met,
but knowing his knowlege of OMC engines, I would bet that he does too.
vin...@relaypoint.net
On Sun, 21 Jun 1998 19:42:42 -0400, Richard Eriksson <re...@vptec.com>
wrote:
Stick with your VRO!! I had an 1987 Evinrude 90HP on my Whaler with
VRO but I wanted some xtra room for my bait tank so I removed the VRO
tank and started pre-mixing my gas & oil. It was a real pain in the
butt. The engine smoked a lot more and tended to foul plugs with
extended trolling times. After 2 weeks I reinstalled the VRO system
and life was good again. Keep the VRO. If the pump fails...fuel
doesn't flow and the engine stops... so there is no running without
oil!
BTW, I just bought a Hydra-sport (couldn't afford another Whaler)
ocean 20 with a 150HP Johnson Ficht system engine. Even during these
first 10 hours with the engine using twice the oil... there is no
smoke! And it is ever so quiet!
Art
>Having an '85, 70 hp Evinrude motor bored and rebuilt. It has the
>automatic VRO oil system and is used on a 17' boat with built in
>30 gallon gas tank. Several people have suggested disabling the
>VRO pump and mixing the oil in the gas tank. On the other hand,
>I have also been advised that Evinrude has redesigned the VRO pump
>several times, the latest design is very reliable and I should include
>a new style pump with the engine rebuild and use the VRO system.
>
>I'd like to use the VRO (if reliable) because of the built in gas
>tank and conveinence. The boat is used for ocean fishing; trolling
>for extended periods of time, with WOT used to beat the thunderstorms
>on the way back to the dock.
>
>Recommendations? Thanks!
>
>Dick Eriksson
Marcus G Bell
K Smith (drif...@nospamwebrider.net.au) wrote:
> You bailed just as you got to the part I'm interested in, the
> fuel flow/delay, your views on my hypothesis as regards the VRO I'll
> value, I'm not just picking on OMC because of the Bill & Dave team
> but the VRO is different to say Merc's.
I started to follow that elsewhere in the thread. Like I said, I got
tired. It's a lot to write.
Your hypothesis is that the piston scuffing presents in the cylinders
farthest away from the VRO pump, where presumably there is greater lag
before the 50:1 "power mix" gets into the cylinder upon transition
from idle to power.
OK, at best, the results are *consistent* with your hypothesis. You
have not proven causality, only a correlation between two variables.
There are other things that correlate with the location of the scuffed
pistons, other causes to be investigated. To prove that one thing
causes the other, you have to vary the first and see if that changes
the second.
You already know which pistons are more likely to scuff. Take a few
motors and lengthen some of the hoses between the carbs and the VRO
pump, to where they're all equal. Then test, test, test. You must run
at least 3 identical motors this way as equally as possible to rule
out random outcomes that appear to match the prediction. Then you
answer the question: Is the location of the scuffed pistons in these 3
motors random, or same as before?
This isn't enough. You must lengthen the hoses on the carbs nearest to
the VRO, to where these hoses are now *longer* than for the carbs
farthest away. 3 identical motors as before. Then you answer the
question: do the scuffed pistons in all cases correlate with the
variable under tight experimental control, namely the length of hose
between the VRO and the carb?
If you haven't done this experiment or one like it, you can't say for
sure if your hypothesis is correct. It is therefore your duty as an
investigator to report any and all asymmetries between the cylinders
whose pistons scuff and those that don't. I hinted at these things in
other posts. For one thing, the path of cooling water is asymmetric
top to bottom. The crankcase puddle drain system may be different top
to bottom. Sometimes compression ratio is different cylinder to
cylinder. Perhaps other differences. To single out one item and speak
as if it's the only one that matters, without solid proof, and without
mentioning other possible causes, is a disservice to those who are
interested in the full story. This type of pseudo-science is summarily
rejected from peer-reviewed journals.
> (i) Merc's OEM manuals regularly "specify" 3 timings, the WOT the
> throttle pickup & the idle, (say 18deg.atdc) whereas OMC don't (as
> Bill points out they don't even mark the flywheel or put it in the
> manual therefore Dave doesn't know)
Merc has some pretty complicated linkages. Maybe they need more
adjustments. Maybe the extra checks serve to eliminate steps
elsewhere. Maybe if you set 2 of the specs, the 3rd will have already
been set.
That said, using data that are a few years old, I do not find that
Merc specifies multiple timing numbers with all that much more
regularity than OMC. Maximum retard is the number least specified by
both Merc and OMC, whereas the Japanese tend to specify that one quite
often. The Japanese differ on other design criteria too, like the
one-piece vs. multipiece connecting rods and crankshafts.
Very often, pick-up is at an RPM with no advance given, or at a
particular advance with no RPM given. Maximum retard is often whatever
it needs to get idle RPM. Maximum advance is of course most often
specified.
> (ii) this is a "potential" problem because if the throttle plates
> fail to be "bottomed" even very slightly, for whatever reason the
> engine can still be tuned in accord with the manual i.e. the engine
> can still be made to idle as per specs rpm by further retarding the
> spark at idle, because the "idle" adjustment is often just a spark
> timing adjustment.
Should a throttle plate fail to bottom, there won't be enough vacuum
to activate the idle mixture circuit, and at idle there won't be
enough mass airflow to activate the main mixture circuit either, and
you'll have a leanout. That's readily apparent on a single carb
engine, perhaps less so on a multicarb mill if only one carb is out of
sync with the rest and isn't properly checked.
Standard procedure in many Merc and OMC multicarb setups is to check
that all plates bottom out, and often check that they all open
parallel. Just be glad that you don't have a Honda 4 carb motor that
needs vacuum gages to sync the carbs to each other. Nothing will save
you from a tech who skips steps in the synchro adjustments, though.
And the more steps you have, the more chance that one will be done
incorrectly.
> (iii) This will further aggravate the "hot piston" if my "hypothesis" is
> right.
Keyword: IF. Again, coincidence is not proof.
> (iv) Merc's oil inject is mostly closer to the carbs, there is also
> sometimes an engine speed related interface with no "lag",
If scuffing were as simple as your "lag hypothesis", then Mercs should
scuff too, except perhaps more evenly because of their shorter hoses.
But even Mercs scuff unevenly. Why?
> (v) But mainly Merc seem to be aware of the very scenario I allude to
> because on some motors they spec. a low 120deg. thermostat for engines that
> are trolled allot, why? if not to protect a hot piston.
You do not know why they lowered the thermostat temp. You don't even
quote a simplified explanation from a service bulletin. As I said
before, it could be so that a cylinder that gets poor coolant flow at
idle will not overheat. It may have nothing whatsoever to do with
this hypothesis of excess idle heat due to over-retard (again, that
heats mostly the exhaust as long as the thermostat temp isn't
exceeded). AND, if you can lower the thermostat temp and make a
difference, it means that there was cooling supply in reserve upon
which the thermostat could call, which pretty much cans your earlier
hypothesis regarding the impeller.
Carl G. Craver
It seems that this has turned into a heated thread. What started out as
friendly advice from OMC trained technitions, has turned into a flaming
match.
My question to all involved who question the compitence of OMC technictions
is, what would you think of ANY engine builder who DID NOT replace the oil
pump on an engine they were rebuilding?
The fact is, automotive engine oil pump failures are almost unheard of, but
any reputable engine rebuilder will replace the oil pump on a rebuild.
My advice has nothing to do with the reliability of the VRO pump. Instead,
it is common sence to replace an oil pump on ANY engine you are rebuilding,
be it a Briggs & Stratton or a Lycoming aircraft engine or anything
inbetween.
I am confident in my abilities as an OMC Master Technition and don't feel
that I need to answer to anyone except my employer (who is more than
satisfied with my performance) and my customers (ditto).
Banter all you like, I for one, am through with this thread.
Carl G. Craver
Evinru...@msn.com
K Smith
Marcus,
Good points; thanks.
Karen Smith.
Richard Eriksson
vin...@relaypoint.net wrote:
>
> On Sun, 21 Jun 1998 19:42:42 -0400, Richard Eriksson <re...@vptec.com>
> wrote:
> Stick with your VRO!! I had an 1987 Evinrude 90HP on my Whaler with
> VRO but I wanted some xtra room for my bait tank so I removed the VRO
> tank and started pre-mixing my gas & oil. It was a real pain in the
> butt. The engine smoked a lot more and tended to foul plugs with
> extended trolling times. After 2 weeks I reinstalled the VRO system
> and life was good again. Keep the VRO. If the pump fails...fuel
> doesn't flow and the engine stops... so there is no running without
> oil!
> BTW, I just bought a Hydra-sport (couldn't afford another Whaler)
> ocean 20 with a 150HP Johnson Ficht system engine. Even during these
> first 10 hours with the engine using twice the oil... there is no
> smoke! And it is ever so quiet!
>
> Art
Did as you (and others) suggested. Installed a new, super-duper VRO
pump as part of the engine rebuild. Everything working very nicely
now!
Dick Eriksson