TO-30, converted to 12 volts, starts easy, sometimes runs smooth, other times it backfires and sputters, acts like a plug wire is out of place or timing is way off. Then it will smooth out and run good for awhile. Cleaned carb, reset points, set timing. Drained gas and replaced fuel. I'm thinking trash in fuel line, but I don't know. What say you? It started after a cold spell. No water in oil, no oil in radiator. I did replace plugs, which needed it (AL 3116), but still popping and sputtering about half the time. When I cleaned the carb i did not have full kit, but I did have a good main gasket and new needle and seat. I did find trash in bottom of carb. Only thing I can think of is more trash somewhere, but interested to see what you say.