Right now, I'm kind of lost in the forest. The fuel/carburation side of this engine seems to be okay. I have played with the ignition timing a bit and got back to where the engine is firing some of the time while being rotated. The easiest thing to try is a different fuel, so I will try some automotive gasoline in the tank to see if that makes any difference. I could take out one piston and con rod and try to get it running as a single cylinder engine. That requires a considerable amount of work and I'm not sure I want to go there yet.