I just had a mechanic do a major rebuild of my Yanmar 2GM20F including new bearings, seals, oil pump, rod bearing, piston & rings, cylinders rebored, etc. Re-installation was completed yesterday and I took her out for a trial run today. I noticed a fair amount of fuel in the water when first starting up and at RPMs > 1400, blue smoke from the exhaust. I was mindful of the need for a break-in period and only ran her up to ~2000 RPM, but blue smoke increased with higher RPMs from 1400 to 2000.
I’ve read that the rings need to seat and that blue smoke is to be expected until that happens... But on the internet there are widely divergent opinions about this, as well as the best strategies for breaking in a rebuilt diesel marine engine.
Is it in fact “normal” for a rebuilt engine to temporarily burn oil? About how many hours will it take for the rings to seat in a 2GM20F? Any suggestions for the best methods of breaking the engine in?
Thanks,
Matt
I’ve read that the rings need to seat and that blue smoke is to be expected until that happens... But on the internet there are widely divergent opinions about this, as well as the best strategies for breaking in a rebuilt diesel marine engine.
Is it in fact “normal” for a rebuilt engine to temporarily burn oil? About how many hours will it take for the rings to seat in a 2GM20F? Any suggestions for the best methods of breaking the engine in?
Thanks,
Matt