Lots of suggestions, thanks. I think I've ruled out all but serious
problems with the engine like injectors or bad compression. Doesn't
look like an easy fix.

Thanks and regards to all to took time to help.

1.156 wrote:

My Yanmar 2gm used to go 3400 rpm -- I did it a couple of times just
to see if it would go the recommended redline. But now it will only
go 2800 rpm full squeeze. And at 2800 rpm (either at the slip or under
way) it puts out a little whitish smoke. I've been thru the fuel
system and so far can't find anything that would be limiting the fuel
flow (new hoses, new filter elements, etc).

Any suggestions of other reasons this thing won't go full blast.?

Thanks