Yanmar Blue Smoke not oil

[George Harlequin]

Have a Yanmar SB8G seeing blue smoke at relatively low revs.Not burning oil, at least oil level seems pretty stable, just had lift pump replaced.Injector new last year.Any ideas?
.

 

[cliff]

Blue Smoke
The engine is burning engine oil (even a small quantity that is hardly noticeable)

•Worn cylinders or piston rings
•Faulty valves or valve stem seals
•Engine over full with engine oil
•Faulty injector pump/lift pump allowing engine oil to be mixed with the diesel

 

[George Harlequin]

Thanks.Lift pump is only a month old

 

[Spyro]

Thanks.Lift pump is only a month old

I think it's an electric lift pump on these engines so probably have nothing to do with it.
Probably just an old worn engine. Does it go away at highter revs when warmed up?
You could try http://www.google.co.uk/products/catalog?q=stop+smoke&hl=en&safe=active&prmd=imvnsu&psj=1&bav=on.2,or.r_gc.r_pw.r_qf.&biw=1152&bih=522&wrapid=tlif134728985896310&um=1&ie=UTF-8&tbm=shop&cid=7322655903242717749&sa=X&ei=FwNOUPfrHYqq0AWthIHYDQ&ved=0CGUQ8wIwAA

 

[George Harlequin]

Thansk, Lift pump not electric.Blue smoke increases with revs.

 

[Nick Marine Eng]

blue smoke is unburned fuel not oil. sounds like the injector spray pattern or possible engine timing issues (to far advanced)

nickroberts02@o2.co.uk

Marine Engineer

 

[Stemar]

If the engine doen't get worked hard, you could try the "Italian Tuneup".

My 28Hp engine is far too big for Jissel, so it doesn't get worked hard enough and becomes smokey over a period of a few weeks. The cure is to blat up the harbour flat out for a few minutes. I start off laying a smokescreen worthy of a WW2 destroyer, but it soon clears and the boat goes faster and the engine runs smoother.

 

[Spyro]

Thansk, Lift pump not electric.Blue smoke increases with revs.

Sorry, my previous boat with a YSB8 had an electric lift pump.

 

[George Harlequin]

Thanks Nick.Assuming injector OK as only replaced last year.The lift pump has just been replaced and I assume that has no effect on timing - possibly excepting it is more efficient now.Injector pump old no obvious timing marks.

 

[AndrewB]

Blown head gasket? If the engine oil level is keeping up, is there any signs of milkiness in the engine oil?

P.S. The "blue" of burning oil is almost transparent, can be quite hard to see. If there is any cloudiness in the exhaust, some water is getting in as well, would reinforce a blown head gasket diagnosis.