MF35 cuts out after warm

[ToadHill]

I agree with most all. The solution is a new coil. I had the problem with a couple of old vehicles I've owned and in both cases the coil failed when it heated up.

 

[twosocks90]

The problem turned out to be wasp nests in the air intake hose before the air cleaner. Under load the engine wasn't getting enough air and it was choking out. After cleaning out the nests it runs great.

 

[WilliamTO-35]

Speaking of wasps, I've had some odd problems that were due to mud wasps plugging up small holes that should have remained open. One such problem was a plugged float chamber vent in a carburetor, which caused the carburetor to flood. Another was a fire extinguisher that didn't work at a critical time because the nozzle was plugged by mud wasps. I now keep a plastic cap over my fire extinguisher nozzles, put on loosely so that it keeps the wasps out but will easily blow off if necessary. A small piece of aluminum foil would probably work as well.