Engine back firing Yanmar YSE8

[hotdogdave]

Hi, my trusty Yanmar YSE8 just goes & goes, until recently. I can't start it and when I try it back fired with smoke coming out of the air intake. I can also hear water gurgling over the hull from the prop, which is interesting since it's in neutral.
Prior to this condition, the only related problem I have had is that it conked out the other day but I thought this was because it was so fouled just before haulout. It started afterwards with no problems.
Just before it stopped for the 2nd & last time, I did notice the revs altering which it never does. I don't do a lot if engine time so the diesel could be over a year old but has fuel treatment added.
After a bit of research on the internet I'm leading to an injector problem. Next trip out I will follow through the fuel path from tank to injector. Somewhere along the way I should see fuel spraying.
Is there a decent quality copy of a manual anywhere that I could get hold of or download that anyone knows about. These engines are simple but I'd like to see pictures if possible. I've heard that undoing certain bolts on the injector leaves you fishing for bits in the bilge!
cheers David Lines
Lea Rig
Duncanson 29

[Lazy Daze Laz]

Use this link for a manual:

 

 

http://www.motoren.ath.cx/

 

 

Then click on the Yanmar link on the LHS down the bottom.

 

Won't work with a direct link to the Yanmar manuals

 

 

[Les Fairwind]

Hi David

 

I sometimes have the engine backfire, hasn't done it for some time but when I asked around I was told it was because it was trying to fire on the up stroke instead of at the top of the stroke.  It only happened while I was hand cranking, and maybe got the timing wrong.  Said not to be a problem if it only happens occasionally, but that's fine for me to say, as it hasn't happened again for several years now.  Doesn't half blow some black smoke out, though, doesn't it !  Makes a mess of the air cleaner element too.

 

When an engine increases and decreases revs, I was told it was "searching" for fuel, it happened to a mate's reconditioned Kubota (Diecon) motor.  I would first check the filter and see if there is any water in the bottom, making the diesel bubble through it to get to the injectors in the first place.  Then maybe the air filter to see if it is good an clean.

 

Anyhoo, here is the link to the Yanmar Help page explaining about bleeding air from the system : http://www.yanmarhelp.com/s_bleed.htm 

 

Good Luck

Les

[Dave - C28 "Ginsyl"]

David,

The revs surging MIGHT be related to overheating, too. They can get pretty hot without the alarm sounding.

Cooee!
Dave

[Maeling]

As Les ays, the revs hunting up and down is symptomatic of insufficient fuel supply, burning what it has an looking for more.  I just had a pair of injectors overhauled at a pumproom at Engadine for $180, I think that included a $50 insert that I bent. As Les says, backfiring sound like pre-ignition (? fuel dribbling in before TDC) hey, I'm no diesel engineer, just trying to figure out why the timing is out.

Geoff Raebel

On Monday, May 13, 2013 6:29:29 PM UTC+10, hotdogdave wrote:

[hotdogdave]

Thanks for the advice. I went out today with a plan to take out the injector and see if it diesel is coming out in a nice cone spray. Removed the top plate held  on by 2 nuts on long studs from the head. That came off but the injector itself did not want to move. From the manual (thanks Lazy Daze Laz) it looks like the injector should not need anymore to remove.
There is a bit of rust though from when the old water exhaust split and sprayed salt water onto the engine. After repairing the exhaust I have been in there with a wire brush, rust converter & cold gal which has probably just made all the bits stick together more!
Tried to undo the fuel line that goes to the injector but that is stuck fast and I only succeeded in rounding the nut! Same with the injector pump end of the fuel line. It is all soaking in (more) Inox so hopefully next time it may shift.
I did get the injector fuel return fitting off (goes from the injector back into the fuel tank). And thought I would try to kick the motor over and it did fire for a bit, so I think I will try to drain the old fuel, and refill with new & injector cleaner and see how that goes. While I don't like the fact that I can't get the injector out, I may get away with not needing to.

cheers David Lines
Lea Rig

D29

[brett]

I've rabbited on about this release agent in another thread here, but this is truly amazing stuff with siezed metal parts and corrosion.

 Reducteur - H 72.

Spray tin, about $30 from Bunnings.

No thirty year old engine should be without it and I don't have shares in the company!

 

Brett

[hotdogdave]

Hi folks

I'm pretty sure I've got a lack of fuel problem. with the seized problems I'm having I'm leaning either towards removing the head along with injectors & injector pump, or the complete engine, and taking it to get serviced.

All this reading I've been doing and in 5 years I have never done any service beyond change of oil and water pump impellor! If I just get it working without ever getting the injector out, or getting the bleed nuts undone I know it will let me down at the worst possible time in the future!

Can anyone recommend a service agent, preferably north side of Sydney (I live in Brooklyn)?

Also if the need arises, a recommended mobile diesel mechanic. I see there are a few listed in Afloat.

[Les Fairwind]

Good luck Dave, I know how you must be suffering

 

I also cannot get my injectors out, soaked in Liquid Spanner, made up a slide hammer, even ran the motor for 5 minutes without the injector retaining clips, no result.  Worried about busting head bolts if I try to take the head off, so in the end I bought a new motor last year.  Still in the back of the van, the old one keeps on keeping on.  Can't beat an old Yanmar  . . .  they just keep on going.

 

One thing started to play up last year that I have not heard of here before, is the alloy top of the fuel filter.  The threads seem to be worn, one started pumping diesel around the edge, more than was being fired in the cylinders, so had an engineer put a new helicoil into it.  Now the others are starting to leak.  Has anybody else had this problem ?  Perhaps something to keep an eye on,

 

Regards

Les

On Monday, 13 May 2013 18:29:29 UTC+10, hotdogdave wrote:

[Maeling]

Totally different engine (Drofin), I had a stuck injector. The problem must have been there for sometime, there was a slight leak around the copper washer and coke residue had jammed the injector, I found out later. I made some longer hold down studs and drilled a bit of angle iron 2 holes fro the studs and a third fit the top of the injector held down by the spill/return pipe nut.  Then with nuts under the iron, I used it as a pusher up, it was slow, 1 flat at a time! When the injector key came clear I got impatient and put a spanner on the top of the injector, screwed out beautifully BUT left the bottom half still in the hole. Screwed it back together BIG MISTAKE ($56 actually) I crushed a bit in the middle that had to be replaced.  The girl in the injector shop said I should have stopped there, she would have loaned me her slide hammer with a fitting to screw into the bottom nozzle holder.  I did get it out with my pusher before refitting, I am going to anneal the copper washers and coat the injector bodies in Neverseeze.

Geoff Raebel

[hotdogdave]

Hi Bett,
Thanks for the info. Have recently purchase said substance, have yet to apply but hopefully it is as good as you say!
For the price I'm expecting it to turn all that it touches to gold!
Regards David
Lea Rig, D29

[hotdogdave]

Les & Geoff have mentioned these slide hammers. Anyone have one that would fit a Yanmar YSE/B 8/10/12? Sounds like what I need.

On Thursday, May 23, 2013 11:14:09 PM UTC+10, Les Fairwind wrote:

[Les Fairwind]

Hi,

 

Easy enough to make one up yourself.  Get the longest bolt or stud you can that will fit from the nozzle outwards towards the engine bay wall, and that has a thread that will fit the injector nozzle.  Then get some gal pipe or square section with 2 end caps, drill through the end caps to fit the bolt or stud, then fill inside the pipe and end caps with lead or something heavy-ish, washers and scrap if nothing else.  Although, if you have a drop press, a good length of heavy thick metal rod is good, drilled through to accommodate the bolt/stud.  Then hammer away  . . .   but don't do what I did, and accidently bang the end of the injector pipe on the down-slide and damage the threads  . . .   :(

 

Regards

Les

["Lea Rig", D29]

An update, spent 2 part days out at the yacht and managed to get the injector out. As per Geoff's idea I used the original clamp plate to 'jack' up the injector. So with the injector out I turned it over by hand and, while I haven't seen it before, I seem to have good pump and atomisation. As my decompression lever is seized it is hard to slowly work up and past the injection timing so I can't see a cone shape from the injector but it definitely is pulsing fuel. Confirm with paper towel in front and it makes circular fuel patches that show up wet on the paper.
I then moved to checking the timing, from the manual I should see markings on the flywheel against an engine notch. While I could see the markings; "10" & "TD"? I could not find a notch. Has anyone come across this before, and if no notch, what is used to line up with the flywheel markings. Also what is 10 & TD, 10 degrees Before Top Dead Centre, and Top Dead centre?
So everything seems ok for fuel & timing, what else could there be. Also won't fire with Areostart, although there were a few (mis)fires going on, no real life. I wonder if I have a valve stuck open/shut. Having a seized decompression lever is a problem so the rocker cover might be coming off, but that might have to wait until next weekend now.

[Maeling]

Dave, these are specialist tools kept by Diesel Pumproom Injector servicing places.  You need to find a friendly pumproom and make a friend.  The other two things here are you really need to identify the injector brand/model and you need to be able to remove the body, top bit, to have something to screw the tool into, which means you need the thread identified to get the right tool.  Failing all that Minnards may be he best bet up your way unless you can find someone more local.

Geoff

[Maeling]

Good one, according Dick Davo in Tassy, pumps don't give a lot of trouble except when the get watery fuel but the Injectors should be serviced every 500 hours. Probably less than $80 ea at your local pumproom, there aren't a lot of pumprooms about.  When serviced they will give you a new copper washer.  The de-compressor should be simple and under the rocker cover. The lever usually operates a cam pressing on the rocker to hold the exhaust valve open. Compression doesn't sound an issue and if she is getting fuel "Mmmmmn" Just check your valve gaps and after doing so, rock the rocker so you can feel there is a gap. Timing shouldn't drift as most of these engines, timing is achieved by shimming the pump up off the cam. I am not an engineer and apart from rebuilding a YSE8 30 years ago know little about them.

Remind me - do you know to wind the clockwork key on the front of the engine (I think before each start) these engines don't have an oil filter and the clockwork operates the blades of a screen that traps sludge.

["Lea Rig", D29]

Hi Geoff, I'm trying to remain hopeful despite my local mechanic telling me to throw it away & get a new engine! Don't really have the $10k for that though but hoping not to need to. He did suggest that carbonising of exhaust valve could be a possible problem however.
My plan is to remove valve cover to make none stuck of damaged. Will check clearances while there & see if I can free up decompression lever.
Yes oil filter is the rotating plate type.
Yes manual indicates shimming of pump alters timing. I assume these are still available from the likes of Lacey etc?

[Kyeemah]

It's your lucky day. Nanni are currently having an end of year sale with prices drastically slashed!. Sadly you are right. you would be lucky to get away with less than 10K for a new engine and self install.