I am going to do a compression check. For this engine you do not remove the injectors. There are plugs along the side of the engine and you install a special adapter to read each cylinder. My Volvo "dealer" should be able to do this. Many have suggested it is worth the expense to assess the level of compression in the engine, and I agree.

Stuck valves are a possibility, but I wonder how they could stick so suddenly after a perfect 4-day run. I also question how enough of them could seize up to prevent starting. There are 2 exhaust and 2 intake valves on each cylinder driven by overhead camshafts, and I would surmise that several cylinders would have to be out for this to happen. I saw no issues when I had the valve cover off, the cams rotated just fine, and the injectors looked relatively clean, despite the fuel problems I saw during sea trial.

I agree with you about the head gasket - plus, I would expect to see a loss of water in the cooling lines. Scored/broken piston rings also seem like a long shot given that the engine ran just fine earlier - as you pointed out that is not something that is likely to happen all at once.

As I noted earlier in this thread, I replaced the fuel pump and piping, had the injectors checked and serviced, and bypassed the boat fuel system to isolate the engine. The Volvo tech suggested that cleaning injectors was a bad idea as he claimed they lose their lubrication capabilities, but I think most everyone else would disagree with that position.

And yes, there is a stop switch, which is working just fine.

Thanks,

Jamie Wendell