generator overheated


undercover

undercover

Member
This is a little westerbeke 3kw that I installed. It quit all of a sudden after running for 10 min or so. Let it cool, and it cranks but doesn't start. I cleaned out a bunch if eel grass that got sucked into the sea strainer. I have spark. Will try some starting fluid, but then it's time for a compression test ???

I'm dreading the results... I fear that the safety interrupts didn't kick in. On a small motor like this, what would get toasted? Head gasket, head, valves, all of the above?
 
Well, one plug out and it's wet (with water not gas) - ugh! At least it didn't appear to hydrolock. Have to remove the damn exhaust manifold to get at the other plug and have room to put a compression tester in there.
 
My compression tester fitting is too big for these small plugs, but using the finger in the plug hole test, the top cylinder has zero compression. :'(

I guess it's time to go deeper and pull the head off (ohc, extra special).

Incidentally, for anyone searching for who makes the engine in a westerbeke BPMG 3.0 kw marine generator, it appears to be the same as a Nissan/Tohatsu 15hp outboard powerhead - NSF15-series. The westerbeke parts book diagrams look like they were copied directly from the NSF15B version.
 
May have dodged a bullet - the westie has a timing belt and the teeth are stripped off a 3-4" section of the belt (enough to go around the crank pulley). Why this happened at 29 hours, I don't know. I guess the belt is 5+ years old.

Now I'm guessing it didn't overheat but the valve and ignition timing went off dramatically - enough to let seawater from the exhaust back in one of the cylinders. It is an interference engine, and keeping my fingers crossed that the valves didn't hit the pistons. Sprayed a bunch of WD40 into the cylinder to hopefully prevent salt water corrosion. If I rotate the crank by hand with the intake and exhaust valves closed, I can feel good compression/vacuum when I put my finger in the spark plug hole.

Cautiously optimistic - will have to wait for the flywheel puller and new belt to do a full compression test.

Doesn't really help you guys with the factory kohlers with their ohv design, but it does point out that the most obvious cause of a problem (overheating in my case) may not be it at all. I'm damn lucky I didn't hydro-lock the motor by trying to restart it a number of times.
 
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