There isn't much about the engine on the site but here's the story.

It is a raw water cooled Yanmar 2QM20H installed in 1980 but was in
fresh water from at least 1985 until we bought the boat (according to
peeled off registration stickers). Judging from other things on the
boat, it never saw salt water except on sea trials and delivery.

The owner's put the boat away one year with fuel in the tank thinking
they would sail the boat the next year. The time on shore stretched
into six years before they put the boat on the market and we bought
it. When it came time to start the engine, all the fuel in the system
had turned to jelly and the fuel pump diaphragm had dissolved.

The Yanmar dealer out in Michigan told us that all the injectors
needed to be replace and probably the injector pump as well. We
negotiated a deal to have the engine work done in Maine after truck
delivery.

The yard here pumped out the tank and fuel system, flushed it, and put
in new fuel and a new fuel pump. The engine was reluctant to start
but, once we got it going it ran beautifully. No new parts needed
aside from the external fuel pump, a RW impeller, and zincs.

It's one of the best running engines I've ever known. When I started
it up this spring, it lit off just like it was warmed up in the middle
of a summer daysail. With the shaft line work described on the web
site, the whole installation runs smoother than I ever thought a two
cylinder diesel could be.

This is a great and reliable engine. I've seldom had more faith in a
piece of machinery (certainly not the one in the airplane I used to
fly) than this one and listening to it throb away on a long leg under
power is nearly as enjoyable as sailing.

--

Roger Long