Are you burning up your "winter" gas? It has more vapor pressure and will "vapor lock" the carb. I did this on my 4010 gasser.....finally saw the gas "boil" in the fuel pump bowl and decided to buy summer gas. Also, be sure you don't have the exhaust manifold heat riser installed in the "hot" position as this will put too much heat to the carb and also boil the gas in the bowl.
If you have a coil issue, you should have weak (or no) spark....easy to test.(after it quits)