/diy/ - Do It Yourself

>>2019117
Caveat: i don't know shit about MARINE diesel engines, but
Yanmar is a decent brand, you see the model on the nameplate, find a service manual for it online, check for a way to measure the compression, borrow the tool and make a measurement, if it's in the range given in the manual then the most important thing is good. The engine looks like it was cleaned to take the pic, there are parts which show it was right up foul before, that's not a bad sign actually, the seller probably just couldn't give a fuck to clean the hose fully. Some parts look way to new too, so there is a chance it was refurbished or at least was in good enough care. There are countless books
<<< like that, which deal with amateur engine maintenance, look for some.