Yammer Problems and Black Smoke

[MARINE ENGINNER]

+1 to Bluebeard

I am reading this thread from the beginning and i suggested also to check the timing.
The timing must be b.T.D.C before Top Dead Center and at no2 cylinder the problem that appears is the delivery valve is stuck or has dirt

ZEX PARTS

this is the article for fuel pumps the brand that yanmar uses if you can find it helpful. hope i helped you to find a solution to your problem


M.E

[Charlie]

Perplexing problem Ferdinand,

Does the manual say that 14* after TDC is proper timimg? I would defer to Marine Engineer in this matter and and agree with him since logically it makes sense that fuel is injected before TDC since compression is needed to ignite the fuel. It seems to me that you have run every check you could on the engine. If you can find a rural diesel shop to inspect your IP you will save a ton of money over a marine shop. I would think it was time to pull the IP.

[Soulflyer1980]

Ok after taking everything apart for the tenth time n checking n rechecking everything I finally found the problem causing me that much headache!! At the injection pump itself, where the injection lines are attached to, is a (don't no the English name) kind of non return valve. So the pressure inside the injection line stays inside the injection line. This way the pump injects right in this second when it needs to inject without first having to built up pressure in the injection line.
These "non return valves" are bolted in from the top into the injection pump, clamped individually to prevent accidental opening, and the injection line fitted right on top of the valves. If you open the injection line nut without using a second spanner to hold the valve it might accidentally open the valve a few degrees of a turn before the injection line nut opens. This must have happened at the workshop at my friend where they worked on the engine.
Now with the non return valve not 100% tight anymore, the existing pressure in the injection line can leak back into the pump but into the oil side of the pump which explains the build up of diesel in my oil. And with the pressure reduced in the injection line, the injection timing for that particular cylinder is off. Too regarded since the IP has to first build up pressure in the line before the injector opens, hence a bad combustion, less power, lower revs under load and black smoke.
After retightening the "non return valve" the engine purred like a kitten and all symptoms disappeared. Took me ages to get to this point, so whenever you open your injection line nut (spanner 17), take a 19 spanner just to counter at the non return valve. Saves you a lot of trouble, months of trouble shooting and four grey hairs 😂

Happy lead free sailing


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[Wotname]

Great find, well done. Thanks also for coming back and letting us all know how it ended

[Badsanta]

Yes, thanks for posting your fix. Good too know.

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[miabellabrian]

have a simple 2 gm engine, I had the same trouble and I worked out the valve clearance was too tight allowing valves open too long, not any problem at low reves but black clouds at high revs,

[HappyMdRSailor]

WHEW!

That was a tricky one! Great find, and thanks for posting the resolution!