Won't run when hot?

[FROSTY:Me]

crank seal sucking air?

[wrenchjockey]

hi,my favourite method of spark checking is to remove the plug,unscrew the cap of the lead and hold the lead near the head.when spun over you need at least 8mm spark.if it is much less than that it will be hard to start and unreliable.if thats ok my guess would be low compression. worn 2 strokes will often start well cold but get much worse as they warm up.if the seals are leaking idling will be very eratic.regards barry