I have a strange one with my Honda whipper snipper.
It runs quite happily for 20 minutes or so, than will slowly loose power. If I switch it off, and restart almost immidiately, it will run for another 10 to 20 minutes quite happily, before loosing power again. It doesnt actually stop, just slows right down !!!!!
Have had the Carby redone, new spark plug, this seemed to fix it for a week.
But now back to it's old tricks again. any anyone seen anything similiar.