wrote in message
...
Sounds like something electrical to me, when the engine is hot something
is breaking down, coil, plug wires, condensor, etc.....Run the engine
with the cowling off to keep it cooler, it will be nosier, but see if
that helps. Something like this can be a real pain in the butt.. Good
luck...

sket


Actually spounds like vaporlock to me. Check how hot the engine is running.
When you shut it down, you may be boiling the fuel in the line or pump.