Yanmar 1GM10 Diesel Fuel Out Exhaust and only 2400 RPM

[Mark Maulden]

Before condemning the engine inards, consider doing a compression test, leakdown test and then another compression test with a "squirt of oil" into the cylinder and compare results.

 

[eusjim1]

Adjusted valves. Gained 200 rpm. Still black water out. Lake water is a little brown, But not bad.

 

[Amos Cape]

Adjust them again! I did mine three times. It got better each time.

 

[eusjim1]

Pulled the head. What a mess. Replacing valves and valve springs. Should then be good to go.

 

[Alan Gomes]

Pulled the head. What a mess. Replacing valves and valve springs. Should then be good to go.

Glad to hear that you are closing in on the problem. Please report back after you take care of the valves. BTW: I also have a 1 GM (not the 1GM10). It's been a good engine so far.

 

[SailormanDan]

I commiserate, my 1GM is also awaiting parts, so I've missed a couple of weekends of decent late season sailing. Good luck with it.

 

[eusjim1]

In conclusion, Turned out to be a crack in the head. Rings were good. Replaced (mechanic did it) head and miscellaneous parts including burned valve. Purrs like a kitten.... for a 1 cylinder.

 

[SailormanDan]

Congrats! Hopefully I'll be up and running in a week or two, will be good to get back out on the water.