oil in exhaust water yanmar 2gm

[miabellabrian]

PLEASE HELP! I have blue smoke now turned into oil/or diesel coming out the exhaust and floating on the water, even at low revs. Still starts and idels ok.This has all just happened today after pushing the engine a little, perhaps I have blown the rings??? .

It is a 10 year old Yanmar 2gm (with a heat exchanger fitted many years ago) in my 25 foot yacht, I had the engine running well, a little warm at revs over 2300 rpm, I suspect that is has an over size prop fitted, as I can push 9 knots at 2200rpm. also can rev higher in reverse ( as lower gearing I believe)
How can I test what is happening with the oil or diesel coming out the exhaust.
Could it be rings, or perhaps head gasket only?? or valve seals?? how do I test, before having to do a big rebuild

please help
cheers
brian

[Wotname]

See response in your other thread re same problem!