Transmission slipping
Dr. Di
transmissions? We have a Hurth HBW-150 R2 transmission that is
slipping, and we may have to alter our cruising plans as a result.. I
really don't want to continue without a workable transmission as I've
seen too many situations where sail alone was inadvisable, especially
in some of the Bahama cuts..
We changed the fluid, checked the linkage, and have been babying it
since first noticed.. It doesn't have an oil cooler, and I'm aware
that might help, but what we have is what we have..
Anyone with suggestions?
Diana
Gregory Hall
"Dr. Di" <dia...@earthlink.net> wrote in message
news:r1htt3tetjlg101ii...@4ax.com...
Yes, I understand that a handful of beach sand does wonders.
--
Gregory Hall
Roger Long
"Gregory Hall" <greg...@home.fake> wrote >
>
> Yes, I understand that a handful of beach sand does wonders.
>
As long as accompanied by a grain of salt, flexibility as to length of time
for cure to be effective, and willingness to buy a new transmission.
--
Roger Long
Edgar
I had a somewhat smaller Hurth (28 hp) that slipped and this caused a delay
in engagement although it did finally pick up the drive but it was a worry
especially in docking situations and I could never be quite sure when
revving up the engine whether the extra revs were in fact being transmitted
to the prop or whether the extra torque was causing more slippage..
Spoke to a Hurth engineer who said that the clutch plates has probably come
to the end of their life and needed changing. Maybe the previous owner of
the boat had not slowed the engine before going from ahead to astern.
Anyway, the bad news was that the cost of the new plates plus labour meant
that it was more economical to replace the whole box at a cost of about
£900.
Considring this, plus the hassle of getting the engine out from under the
cockpit to remove the box I decided to put back a new engine and gearbox
while Ii was at it as this would add value to my yacht as well as ensuring
reliability.
These boxes are small and precision made and should engage with a hard
'click' and no slippage so I cannot offer much hope for an easy solution..
Marty
You cannot buy a mechanic in a can....
Cheers
Marty
Jere Lull
> Does anyone have experience with an anti-slip additive for marine
> transmissions?
>
> We changed the fluid, checked the linkage, and have been babying it
> since first noticed.. It doesn't have an oil cooler, and I'm aware
> that might help, but what we have is what we have..
>
> Anyone with suggestions?
>
> Diana
I do believe you should pull the tranny, break it down, and replace the
worn parts. When a wet clutch stops working, there are often other worn
parts. I'd pay particular attention to the spring(s), which do get weak
over time. (Note: this is from motorcycle maintenance; I've not had to
touch a boat transmission except to change the oil.)
--
Jere Lull
Tanzer 28 #4 out of Tolchester, MD
Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/
Bruce in Bangkok
wrote:
I guess the first question is how do you know that it is slipping?
But if you are positive that the transmission is slipping then the
only solution is to rebuild it. A Hurth is a very simple transmission
- two clutch packs and a second shaft and gear set to reverse the
output rotation. If it is slipping then the clutch plates are worn and
nothing you can do is going to make any real difference.
An oil cooler won't make any difference at this stage but if you do
rebuild then adding a cooler might make the rebuilt box last longer
next time.
Foley Marine is a good source of parts and information regarding Hurth
boxes although there are plenty more on the net.
http://www.foleyengines.com/Home.aspx
Bruce-in-Bangkok
(correct email address for reply)
Dr. Di
no way to do it.. But the transmission overheats, and the boat speed
through the water decreases without any change in engine RPM's..
Thanks for your input Bruce, as well as everyone else who attempted to
help.. I guess it's time to consider pulling and rebuilding the
transmission..
Are you really in Bangkok? I think Thailand is a great place to visit,
with very friendly people... At least I found it so...
Diana
Brian Whatcott
wrote:
>I didn't measure the differences in shaft speed, mainly because I have
>no way to do it.. But the transmission overheats, and the boat speed
>through the water decreases without any change in engine RPM's..
/snip/
These days, non-contact or optical tachometers are cheap - and popular
items at hobby shops. Look at this one, for example. $28.
Stick a piece of tape on the shafdt and have the tach look at it.
<http://h1070530.hobbyshopnow.com/products/description.asp?prod=HAN156>
Brian Whatcott Altus OK
Roger Long
>
> These days, non-contact or optical tachometers are cheap - and popular
> items at hobby shops. Look at this one, for example. $28.
> Stick a piece of tape on the shafdt and have the tach look at it.
>
> <http://h1070530.hobbyshopnow.com/products/description.asp?prod=HAN156>
>
Thanks for the good link to what I was suggesting to someone else for
verifying their tach. I had no idea they had gotten so cheap.
The OP doesn't need to bother, however. Unless he has a variable pitch
prop, the only way the boat can slow without the engine RPM changing is for
the hull resistance to increase (picking up a lobster pot for example) or
for the transmission to be slipping. Slipping clutches get hot. The
probability of slipping is 99.99% in this case. He's going to need that $28
bucks to get his transmission rebuilt.
--
Roger Long
tsm...@gmail.com
> "Brian Whatcott" <betw...@sbcglobal.net> wrote
> > These days, non-contact or optical tachometers are cheap
>
> Thanks for the good link to what I was suggesting to someone else for
That would be me, I think. Very cool at that price. I'm not sure how
I'd get it to work on my saildrive though.
-- Tom.
Bruce in Bangkok
wrote:
>I didn't measure the differences in shaft speed, mainly because I have
>no way to do it.. But the transmission overheats, and the boat speed
>through the water decreases without any change in engine RPM's..
>
>Thanks for your input Bruce, as well as everyone else who attempted to
>help.. I guess it's time to consider pulling and rebuilding the
>transmission..
>
>Are you really in Bangkok? I think Thailand is a great place to visit,
>with very friendly people... At least I found it so...
>
>Diana
>
All the Hurths I've seen got pretty hot. hot enough that, while it
didn't burn your hand, you didn;t want to keep your hand on it very
long.
I am assuming that you have checked the oil.
Yes I am in Thailand, I live here permanently. We spend about half
our time in Bangkok and half in Phuket where we keep a 40' sloop.
Roger Long
> I'm not sure how I'd get it to work on my saildrive though.
There must be some rotating part of your engine visible. You can stick the
piece of reflective tape on something like the pully that drives the
alternator belt. This won't help you with clutch slippage or reduction gear
ratio differences. It doesn't sound like you have the former though and the
latter is pretty unlikely in a package unit like a sail drive.
--
Roger Long
Edgar
"Brian Whatcott" <bet...@sbcglobal.net> wrote in message
news:90c3u31o0799ln179...@4ax.com...
Sounds interesting, but why does it care how many blades are on the
propeller if it is only looking at the shaft?
Wayne.B
wrote:
>Sounds interesting, but why does it care how many blades are on the
>propeller if it is only looking at the shaft?
It is designed to check RPMs on model airplanes where there is not
much shaft to work with.
Brian Whatcott
wrote:
>
Optical tachs sold to hobbyists often have that sophistication - that
you don't need, but can work with easily, I imagine?
Brian W