Yanmar 6LY smoking - any ideas???

[Arcee]

I have a 315hp yanmar that is blowing lots of white, maybe blue smoke when cold. It then reduces a bit when up to temp but is still there. Then when up on the plane, 2200 rpm and above, there is sign of black smoke. Its a bit hard to tell because of the underwater exhaust but definitely looks darker. The engine sounds fine, maybe a bit of tappet noise.
I have cracked each injector one by one and there is a noticeable change in tune with each one.
Also have just had the injectors serviced by a reputable technician, new nozzles etc.
I am looking for some tips before chucking a whole lot more money at professional attention.

- Richard

[Badsanta]

when was the last time the bottom and prop was cleaned?

[djmarchand]

Arcee:

Post your problem on boatdiesel.com. Be very specific about what you see and how the engine runs. Some additional questions that will need to be answered before the pros on boatdiesel can advise you:

1. Does the white smoke dissapate within a few feet of the boat (steam) or does it linger (unburned fuel)?
2. Are you using any oil- cause of blue smoke?
3. At wot does it hit 3,300+ rpm in gear?

David

[Chuteman]

More Info.....
Engine Hours?
Tappet noise - Last time Valves were adjusted?
Injectors serviced - did you have similar symptoms before service?

[Arcee]

Thanks for the replies.
The bottom is clean and prop is good.
The smoke lingers - definitely not steam and I think leaves a bit of an oily sheen on the water. Not using any oil and the boat can reach 3300 (by revcounter)
Not sure about engine hours as it was second hand when installed and i have only owned the boat for a year, the symptoms were there before injector work.
Valves have not been adjusted recently - is this a possible cause?
Cheers, Richard

[Chuteman]

So the symptoms did not improve with injector servicing, interesting.

Valves - certainly does not help if not in spec - Yes can contribute

Not burning oil - is it making "oil"? - is the engine crankcase overfilled?
meaning diesel is getting into oil system?

What about fuel injection timing? was that checked?

[Arcee]

Timing has not been checked. Oil level hasnt changed so its not making oil