I've had the same problem since January and can't figure it out. My engine will start missing intermittently not consistently while running over 3000rpms. This will come and go, I can run for 30 minutes just fine then it will start missing as it is doing it you can see the fuel spurt in all 3 carbs. I was sure it was fuel related and replaced all fuel lines, both fuel pumps, primer bulb, both fuel filters and rebuilt all 3 carbs. Still had the problem and noticed a head gasket leak, replace both, still does it. Can this be electronic, I didn't think so because it comes and goes. I'm just amazed it will run great then on the next take off run so poor. I would appreciate any suggestions.
thanks,
Dave