Stihl 039 Will not run when hot.

[AKMountainMan]

So I have an 039 that has been been very reliable until last year. The problem seems to be if I run it hard it starts dying when I let off on the throttle. I usually can get it to restart with full choke a few times but eventually it will not restart. Last fall I had the same problem but I thought it was the carb so I replaced it. I have checked the compression, 145lbs cold, I have changed the fuel line, fuel filter, air filter, spark plug, I have checked the crankcase seals both with vacuum and pressure and everything holds great, including the carb boot and the impulse line. I checked the fuel tank vent and it works. The piston looks in great shape and the muffler is clean. The one thing is I tried using a Snap-On spark tester and I get nothing, I hold the spark plug against the block and pull it over I get a very small, almost impossible to see, spark. I can't seem to find a consensus on how to test the coil, but I have had coils that failed when the get hot on other equipment so I am thinking it might be the coil. Any suggestions?

 

[carhartt]

Id order a coil for it. I have found aftermarket work just fine. You can test coil with a digital ohm meter if you can find what the readings are supposed to read and if I am not mistaken you can take readings from 2 different locations on the coil.
Check the magnets on the flywheel also and make sure your gap is set correctly.