Yanmar Smoking and Making Oil

[Chief Engineer]

True diesel engine compression testers are a pricey bit of equipment for sure.

That any decent diesel mechanic does not have one is beyond me.

Keep us posted on the pitch issue.

Finally, as I scratch my bald head, do you have any other items on the front of the engine that may be taking power? Refrigeration, additional alternators, fire pump?

[James S]

I don’t think its the back pressure but if you need to check it it needs to be done between the exhausts water injection elbow and water lift...or at the water-lift, but not at the discharge outlet.
Is that the elbow he's talking about?

[Tspringer]

Chief... no added stuff. In fact, we removed a giant engine driven refrigeration compressor during my refit replacing it with a DC powered frigoboat keel-cooled system.

I did have the alternator bearings and brushes replaced and it is a Balmar 100 amp model but its the same alternator we have used all along. The alternator is the only thing other than water pump the belt turns.

The mechanic says he has a compression tester but not that will fit our engine. He has apparently spoken to a number of other mechanics in the area and they all say the same thing.... they dont have one mostly because they have never run into a small Yanmar that actually had bad compression... "they just don't break" is the comment. Whatever.

At this point it looks like we are going to get hauled out and check/reset the prop pitch.



Terry

[sigmasailor]

Hmmm, mechanics without proper tools. Any engine might get leaky valves or ring problems; even Yanmars. A compression tester is something you need to diagnose the problem. By the way isn't it normal for injectors to clamped down the way you described? I never saw anything else and do not understand why a normal universal diesel compression tester would not work. A lot of diesel engine manufactures use the same components (Bosch being a well known brand) so you do not need that many adapters to be able to service a lot of engines.

Good luck with the prop (I studied some via Google); maybe it gets stuck on on some hardened bits because it wasn't used a while?

[Steve W]

can you stand a ridiculous idea? try motoring with the sails up and see if the engine will hit the target rpm with an assist from the sails. If it does, it might confirm the prop needs re-ptiching. Sort of like gaining speed down hill, the sails might overcome the resistance from the current prop setting and allow the rpm to increase. Sorry if this is a double post, airport WiFi is acting up. Good luck and hang in there!

[Cheechako]

sounds like it has to be a prop pitch issue at this point... makes 4000 in neutral, makes 2950 under load, runs fine without black smoke until you go for max throttle right? There are divers who can change an old school Max Prop pitch here in Seattle, any out there? can you turn the prop shaft in neutral by hand? How much resistance is there? If your boat saat a lot without use, the shaft could be badly corroded inside the cutlass bearing... now tearing away at the bearing... This is where they almost always corrode due to oxygen depletion in the bearing...

[malbert73]

I recommend going ahead with haul and service propeller.
The only way to exclude the prop is if you had a fixed prop.
any feathering prop can jam short of full deployment, and a diver would unlikely be able to tell this underwater.
You'll kick yourself at the end (not that I can second guess your doubts initially) that it was this easy, but I would be extremely surprised if it is not the prop pitch.
Please do let us all know!

Another intermediate test is to run in reverse and see if the same thing happens. I believe Yanmar trannies have a decreased ratio in reverse so would load your engine less, and in theory you would get more rpms. If this is fine and no smoke, then likely too much pitch in forward.

[Fishman_Tx]

I did have the alternator bearings and brushes replaced and it is a Balmar 100 amp model but its the same alternator we have used all along.

Man oh man, lots o' problems. I'm no expert but just shootin' in the dark here..
I had an new/rebuilt alternator once that for some reason would bog the engine down, but would idle ok. Replacing it fixed the problem. Craziest thing i'd seen as I thought it would bog at idle and not at speed.
Like I said, just shootin' in the dark......
Good Luck!

[Boracay]

Is it possible that the loss of power and the black smoke is caused by a collection of problems.
1) The prop pitch looks fine for your boat before it was loaded. May be a little coarse now.
2) 4000 hours may be considered old for a light turbo diesel. A loss of power may have occurred.
3) Is it possible to run a string and cloth through the exhaust tubing, sort of like a chimney sweep?
Is there any engine speed at which the engine does not blow black smoke? If this is true that is the point at which the propeller is loaded fully. Any more is overload.

[PieRatPeat]

Originally Posted by Tspringer

Chief... no added stuff. In fact, we removed a giant engine driven refrigeration compressor during my refit replacing it with a DC powered frigoboat keel-cooled system.

I did have the alternator bearings and brushes replaced and it is a Balmar 100 amp model but its the same alternator we have used all along. The alternator is the only thing other than water pump the belt turns.
...

Terry

I'm no diesel mechanic, so normally I'd stay out of this, but man, I really feel you pain. Given that you've not found the problem, maybe a fresh approach and some basic analytics can help, so let me take a cut at this:

First, some things we know (or at least believe to be true):

1) The engine sat unused for over six months during rework.
2) Components (turbo, ext) were removed for a clean-up.
3) Two problems appeared when engine was put back into service (fuel in oil and black smoke in exhaust).
4) New pump seems to have fixed fuel in oil problem.
5) There are two injector models, didn't see that correct nozzles for your engine/pressure has been confirmed.
6) Diver indicates prop & shaft are clear.
7) You claim that nothing was added to the engine to increase load, BUT you did remove a refrigeration compressor and replace it with a DC-powered frigo-boat system.
8) Alternator bearings & brushes were replaced.


Now, some suggestions, based upon my review of of the entire thread (I try to give credit where due, and I *think* I got the post numbers right - apologies in advance for errors). This might not be worth more than you're paying for them, but might help spur some lateral thinking:


Suggestion #1: As someone pointed out (in post #110) "if engine is overloaded there must be some other drag on it". I went through the entire thread looking for clues and anomalies, and the only thing that made my hair stand on end that nobody seems to be commenting on is the fact that you pulled a compressor from the engine and converted to a DC-powered frigoboat unit, which seems like a fairly substantive change in configuration.
Agreed, pulling the compressor would presumably reduce drag, but then you added a corresponding load to the alternator (plus also a hull-mounted cooler, which adds drag to the hull?). Are you sure that all these changes aren't putting extra load on the engine? Coupled with other changes (the 2000lb added weight, maybe the injector nozzle issue?) could this be your problem? If the frigoboat unit is drawing a significant amount of current during your engine tests it might be loading things more than you think.
Can you shut it off, maybe pull the alternator belt or otherwise verify that all this isn't loading your engine up? Just a thought as it does stand out as a rather significant configuration change.

Suggestion #2: You state (in post #21) that you're sure the engine is now using clean fuel, but I didn't see anything about draining and replacing the fuel. Are you assuming the new filter guarantees good fuel? It did sit for quite a long time, and the injectors were quite fouled when the problem appeared. Could this been something as simple as a problem of stale fuel ?

Suggestion #3: Someone called out the fact (in In post #61) that there are two models of injector for this engine, with differing fuel pressure settings - are you sure you had the right injector nozzles for your model? If you had the injectors for the non-turbo engine I would assume the problem would be not enough fuel, not too much, but it's an unanswered question. I'd confirm this before abandoning the engine!

Suggestion # 4: Someone suggested (in post #71?) that the added 2000lb of weight could be the problem, coupled perhaps with a marginal prop pitch? Someone suggested that you dump your fresh water and try again. This seems a stretch on its face, but coupled with other factors (bad injector nozzle setting, other potential loads on the engine?) you could have passed a threshold, so you might consider going even further and perhaps drain fuel & offload anything heavy/movable and trying another run. Oh, and if you've been doing these trials with a full crew, consider trying with just one or two aboard. None of this would require a haul-out, so it seems to be worth a shot...


Okay, again I'm no diesel expert, but thought this could serve as a level-set for those who are. Good luck, and really hope you nail this soon...

- peterd

[Navicula]

could it have jumped a tooth and the timing be out, you have replaced everything and the prop is fine...........I give up, but at this piont I need to know

[Gene :^)]

Wow, I am really surprised. I want to apologize for being a strong proponent of the Turbo replacement (dart) which put a dent in your budget. I really thought that was the problem. I also apologize for doubting your cleaning process. It appears that you were gentle as you suggested. Even the shops I called cringed at the idea of cleaning the turbo as you did.

I have been reading, re-reading, and thinking about this non-stop. I will reply when I gather some thoughts.

[malbert73]

I disagree with exhaust back pressure, or alternator, or refrig unit as possibly causing the issues- they would cause problems in neutral as well as in gear. The only issue is when engine is put in gear- ergo under load of the prop.
4000rpm in neutral, no smoke
2400 rpm in gear ++ smoke
this sounds like the Max prop is not deploying fully from feathered (ie maximum pitch) until proven otherwise.

[um saudade]

Terry,

Sorry this is taking so long to sort out. I was the initial proponent of the turbo being the issue so shoot me. In my defense, I would have to say that I would not have replaced it but would have taken it to a decent shop for testing.

I think this is a big problem here. You don’t seem to have any mechanics that should truly be called mechanics! Not testing compression because you don’t have the tool!
I am old school in that you either fix the gizmo of you don’t charge for the work.

That’ however is another story. If I have an issue with a diesel I have a couple of independent shops who are far better that the dealers in doing pump and injector work, as it is all they do. The same should be true for turbos. You get it tested, pay a small fee for the checkout, buy a new set of gaskets and put it back in service, knowing that it works.

My first turbo was in a ’67 Corvair Spider and I have mistrusted them every since.
Too delicate and fussy to belong on a boat when you are far, far from shore.

That said: I still believe there could be a restriction in the muffler or somewhere in the exhaust system itself. While I am not a fan of punching a hole in megabucks exhaust hose, that may be the way to check it out. Usually you can find someplace that can be threaded to 1/8 pipe and you install a low pressure gauge.

When all is working as it should the exhaust flow (not pressure) spools up the turbo, boosting the pressure on the intake side and forcing in more air to match the more fuel the governor is telling the pump to produce. You should get a little black smoke on acceleration as the boost is lagging the governor setting.

You are not getting the boost you should, but due to what? We have ruled out turbo and intake. You still have not positively ruled out exhaust restriction.

Try tying off to the dock and running it in gear at a low rpm for at least 15-20 minutes. I would like to se if the engine cleans up running at just enough load to burn well and get all the unburned fuel out of there. As an aside, if you find the magic button and the problem is solved this engine that is not swimming in unburned fuel will not just suddenly run clean! It will take some run time to get there.

I agree with the posters who suggest lightening the load and the boat and seeing if symptoms change. It is a cheap test. But pay heed to the above paragraph. It will need a little time to clean out before it looks like a clean exhaust stream.

Um Saudade

[ViribusUnitis]

I can't belive your still messing with this. I would have figured that it would have been fixed long ago.

I still belive that your main problem is the guy on the end of the wrench. He's the mechenic of a yanmar dealship. Any dealership mechenic by default would have any "special" tool for the engine. Clearly if they don't have the "special" adapter for a compression tester, they're incompetent. Any mechenics shop worth their salt would have a leak tester, and a compression tester. It's past time for find a diffrent mechenic. The boat is mobile, it's probably past time to make use of that fuction and go to a diffrent mechenic.

Before you let the guy work on your boat, you need to have a talk with him, and figure out if he even knows what he's talking about. If it's clear he doesn't have a clue, keep on going.