[Darrin Christen]

I had the same problem. I thought is was a bad rod bearing or broken piston. When I took the heads off I found a smashed chunk of carbon on top of one of the pistons. I probably could have sprayed something through the spark plug hole to dissolve it but I already had the generator out and apart. I would try some carbon cleaner before taking it apart. You can try a marine dealer who sells outboard engines. They carry several different types of carbon cleaners you spray into the engine while running.