Yanmar Smoking and Making Oil

[Navicula]

YANMAR DIESEL TIMING
as a result of timing misalignment. The misalignment was caused by at least 2 “diesel gurus”, who re-installed the injection pump after pulling the gear case cover . Injection timing is controlled by brass shims between the pump and the gear case cover. INSIST on a timing check every time the injection pump is re-installed.


can we please eliminate the timing issue

[never monday]

Originally Posted by TACK OFF

YANMAR DIESEL TIMING
as a result of timing misalignment. The misalignment was caused by at least 2 “diesel gurus”, who re-installed the injection pump after pulling the gear case cover . Injection timing is controlled by brass shims between the pump and the gear case cover. INSIST on a timing check every time the injection pump is re-installed.


can we please eliminate the timing issue

please define which engine you are referring to

[Tspringer]

The injection pump has not been removed, not by me during all the refit work and not by any of the mechanics who have worked on this engine. I struggle to see how the injection timing could be off given no movement of the pump, but I am not ruling that out and will look into checking it.

NM... I will run the engine under load tomorrow and remove the hose you indicated and post back with the results. Do you feel I need to sea trial or can I run in gear at the dock for this test? When I next run the engine under load I will also remove the breather line from the valve cover and see if I feel any pulsing or pressure. When the mechanics checked this before it was sitting at the dock in neutral with no load.

Exhaust back pressure clearly must be checked and other than the test NM requests this is my next thing to attack. The exhaust is fairly simple. The mixing elbow has a short length of 4" diameter hose going directly downward that is about 6" long. This connects to a large fiberglass 90 degree elbow that has a 3' section of the same 4" diameter hose attached to it which ends at the fiberglass water lift muffler. The same hose exist the muffler vertically going straight up to a large fiberglass vented loop that ends directly under the helm station. The hose from the vented loop goes back down and turns rearward passing through a bulkhead, makes another 90 degree turn with another fiberglass elbow and then runs straight out the back of the boat. All of the hose and the fiberglass elbows and such are 4" inner diameter.

I had not thought of a setup for checking the internal state of the hose and muffler like that posted for inspecting plumbing. That looks like a great idea and I will see about checking into having a plumber bring one out or if I can rent one.

At this point I see 3 possible issues:

- Bad compression not allowing the engine to generate the power it should
- Exhaust blockage causing back pressure and reduced turbo boost
- Bad injection pump or timing



Terry

[never monday]

Originally Posted by Tspringer

NM... I will run the engine under load tomorrow and remove the hose you indicated and post back with the results. Do you feel I need to sea trial or can I run in gear at the dock for this test? When I next run the engine under load I will also remove the breather line from the valve cover and see if I feel any pulsing or pressure. When the mechanics checked this before it was sitting at the dock in neutral with no load.

under load at the dock should give the answers needed.
The hose I asked you to remove is the boost pressure signal line to the IP.
When the turbo builds boost. Some is transmitted to a diaphragm valve in the IP. I don't remember if your's retards or increases fuel under boost.
While your running it. I expect strong air flow from the hose. I also have a feeling the resultant loss of pressure at the pump. Will cause a decrease in the smoke. I don't have the JH2 book at home with me so I'm working off of memory.

Don't screw with the timing......yet

[Chief Engineer]

I am just curious at this point, how long was the engine run?

I have run a few vessels at the dock at what we called "dead push"..in gear but not full throttle.....just below the point that smoke occurs.....I realize this is anecdotal but with all the unburned stuff in your exhaust lines you might be blowing soot for a while.....

I also know from your previous posts that you scrupulously cleaned out any "coke" in the exhaust riser and you had not done anything to the exhaust hoses i.e. reduced size.

[James S]

I hate to have to re-read all the posts so I apologize if this has already been answered.
Have you tried running the engine at high RPMs with the engine hatch open?
I know I'm grasping at straws here and you have tested the turbo...but I'm thinking you did that with the hatch open...but just wondering if when the hatches are closed are you getting enough combustion air?

[sigmasailor]

Hi Terry,

Are you really sure the correct nozzles were installed? Bad vaporizing of fuel will also result in under performance of your engine. Since the badly vaporized fuel will continue burning (badly) at the end of the 'bang' stroke and beginning of the exhaust you loose power and will get black smoke. Like I mentioned before; even with the wrong nozzles it is possible to adjust injectors to 'pop' at the correct pressure setting but they would not work in your engine since they do not get the amount of fuel required.

Bad timing (unlikely) will cause the same problem; this is easily checked by a good mechanic.
I would also like to know about compression on all cylinders; maybe one isn't doing its job? While you are checking: get those back pressure and turbo boost readings in the current set-up.

4000 Hours is nothing unusual for a maintained diesel engine; when compared to a car engine this relates to something like 175.000 miles: barely even run in. I drove my 1.9 VW TDI to well over double that without any engine problems (unfortunately a wheel joint broke here). Some 30 years ago in my engineering days we wouldn't consider serious overhaul until after 10.000 hours (and those were diesels made in the fifties).

[never monday]

Terry,
call or email me when you get some answers. i'll be away from the computer most of the morning.

[Gnitfar]

Hint...Typically, an internally rusting mixing elbow (more inevitable in older yanmars) in their progression, usually rust more and more during winter lay-ups, or when not run for months causing progressively more and more restriction. One customer quoted, it ran fine in the fall before lay-up, now it smokes black thick soot, turbo won't spool up, and has no power, what gives?

[Captain Bill]

Somewhere earlier in this thread terry reported that he had cleaned the mixing elbow.

[sandspur]

Everyone is missing the key, ( Smoking & MAKING OIL !!! )
get the inj. pump done

[Gnitfar]

Originally Posted by Captain Bill

Somewhere earlier in this thread terry reported that he had cleaned the mixing elbow.

Quoted from page one...
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I also removed the exhaust elbow and cleaned it out with wire brush, cleaner and a hose so it is clean and not blocked up.
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If the riser is absolutely clear, without doubt, than this possibility can be ruled out, however a check of the rest of the exhaust shouldn't be ruled out. Mice and even birds have been known to make a nest in exhaust systems!

[Captain Bill]

I agree with the exhaust not being ruled out, Just figured you had missed the statement about the elbow in this long thread. One thing for sure, when this is all finnaly figured out we'll have all learned a lot about turbodiesels.

[Cheechako]

is there a waterlift muffler? maybe it's restricted inside? (Rat, soot accumulation, baffle broke loose) I sthere a short piece of exhaust hose you couldld take loose and see the buildup?

[danielgoldberg]

Well, I'll tell you one thing, you better figure this problem out and tell us all the cause and solution! I feel like I'm hooked on a daytime soap and I can't wait for the next episode.

Keep your chin up Terry! We're all pulling for you!