From:John Yushkevich
Subject:RE: bad running when hot Date:Mon Oct 27 14:44:24 2014
Response to:5396
With all due respect to your Magneto specialist, could still be some partial breakdown of windings in either the coil or a defective condenser. Even though his work may be top notch, you can't get away from the fact that a magneto is an electrical/mechanical component. I do 90% of my own mag work (less winding my own coils) and I find that, most of the time, with a problem like this the problem lies with the coil. On these mags, the condenser is wound into the coil.
If you can, test the spark strength with a test plug and then again after it is hot and compare the spark intensity.
Reach out to your Mag guy with assistance. I'm sure he is proud of his workmanship and if you suspect spark may be the problem, he will be as determined as you to resolve the problem.
Good luck.

just finished a major rebuild on 22 Ace start from cold runs perfect and smooth as it get hot say 5 minutes starts to misfire when you open the throttle it's flat won't pick up. The mag has been rebuilt by a very well respected company,has new HT leads, anyone else suffered the same problem ?