swear at it call it a few new made up names probably wont fix it but youll feel better.
as edb has suggested a bad mag often only show when it gets warm. as heat increases resistance. same thing you cant send a coil for hot testing it passes today and it will fail next week thats why the only way with a suspect mag is a proper rebuild. only use vacuum impregnated coils for best reliability.
and now the rest of the story...... drilling out the passageways of the carb did not help. sent the mag out,put it back on,pony now runs like new.thanks for the help guys.Bryan