[olson34]

Regarding Yanmar engines, I once was finishing up a rough-motion bar crossing part of the delivery on a 36 footer with a 3 cylinder Yanmar, and we were rolling enough that some air in the tank got into the line and stopped the engine. We had enough wind at the time - motor sailing - that we could wait until the water smoothed out some and then the owner started bleeding the engine with the built-in bleed screw/bolt.
Well, that bolt is hollow, and with a tiny bit too much tightening force it... broke...
Wind held and we sailed into the marina and pulled into an open slip without hitting anything. (!)
In a small town it took an extra day to find a same-thread bolt and modify it to fit so we could bleed out the Yanmar and run it again.
Than damned little metric bolt turned out to be cast aluminum, and brittle when torqued on too much.

The two cylinder might be different, but still something to keep in mind.