Yanmar diesel smoking/ black soot

[sailorchic34]

One other gleam I had was to check the injector limiter setting. That's the acorn nut on the front of the timing case. That sets how much fuel the injector pump will pump. Inside it is a small spring and I think a brass nose. if the spring lost temper or the brass bit deformed, that would change the mixture and could easily cause lots O black smoke.

Generally small movements 1/8 turn at a time clockwise lean the pump out, counterclockwise riches the mixture. Or one of the springs between the pump and governor has lost temper. Either would cause black smoke too.

Note that this (the injector limitor) is set at the factory and is generally not for the user to adjust as bad things will happen if the engine runs too lean.

[Sun and Moon]

Have you checked the engine temperature with a hand-held temp gun? You can get one for $35, maybe less. I think one of the theories still in play is that the engine is cold and doesn't burn efficiently. After 10 mins maybe it finally reaches temperature.

[Nucdad1]

Putting it all together here is my two cents worth. If you (maybe) overheated the engine I find it incredible that you had an event that resulted in the fuel system (pump or governor) being changed that would show up for 10 mins and go away. If this was my project I would verify the exhaust was NOT restricted in someway. Then verify the valves were adjusted to spec. Then check the injectors all ?GM injectors are easy to clean and inspect. just "You tube it"! I had a 1GM that finally came down to pulling the head the problem was the exhaust seat after 25 years was just shot it smoked for 10 minutes then cleared up on heat up. Yes it cost some boat jewelry $$$$, but a new head gasket and new head and a few hours no black smoke the power is back. Just start at the top and go backwards. these engines will last for years unless you are using them everyday all day most don't have that many hours on them. Do the simple stuff diesels will take some abuse. Kiss it "Keep it simple"
Diesels need 3 things (air fuel and rotation)

[Bronk33]

Here is the mechanics work order again.
I'm scratching my head looking at it... He smelled bad/horrible fuel. Then replaced all fuel parts again.
Started it up with ether.
Never bypassed or changed out.

Does this sound like a big case of bad fuel


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[Gone2long]

Originally Posted by sailorchic34

Nope, too much fuel is black smoke or injector timing, but timing is not effected by temperature.

My engine has a piston with three broken rings it did not smoke at all. Used oil like a pig, but no smoke.

Blue grey smoke is oil, white smoke is water.

Found your posts very insightful. I am having starting problems, documented on a current thread where I was asking help on how to bleed my fuel line.

Another issue, however, is that, when the diesel IS running, it blows black smoke on high revs. Is this normal, or indicative of injector or other problems?

Pardon my ignorance, and thanks for your insights,

G2L

[Wotname]

Originally Posted by Gone2long

....
Another issue, however, is that, when the diesel IS running, it blows black smoke on high revs. Is this normal, or indicative of injector or other problems?

Pardon my ignorance, and thanks for your insights,

G2L

Black smoke is not normal at high revs unless it is just a tiny amount at WOT (wide open throttle). It indicates too much fuel is being injected for the RPM reached.

The most common cause is a fouled bottom or fouled prop or overproped boat. In these cases, the engine can't obtain full RPM so the injector adds more fuel to try to get to max rpm corresponding to WOT.

The way to check is to see if you can reach max rpm at WOT while moving a hull speed (or less) in a flat calm sea. If max rpm is reached under these conditions, there should be no or almost no black smoke. If max rpm is not reached and black smoke is present, then issue is normally the boat or prop, not the engine.

[tdh1849]

Bronk, I may have posted this before, but get the tel# for "Complete Yacht Service" the Yanmar dealer in Ft.Lauderdale and ask to speak to the owner Mark, (USMC) and tell him Pat N. formery of Ft.Lauderdale now in Tampa told U to call. He knows all there is to know about Yanmars.
I may have posted this earlier, not sure. He is one of the Good Guys and will help U if he can.