How's the compression? When you say the starter will not crank fast enough, it reminds me of when I had bad head cracks /dropped valve seat - when cold, the cracks were small and there was enough compression to start the engine. When hot, it had to be going pretty fast to bump start it. Same type of scenario I suppose for too-tight valve clearances - when cold, it's fine; when hot, valves not seating properly. Mine ran fine at higher speeds, wouldn't idle well when hot. I hope it's not the problem you're having, but if it isn't anything else... When you try starting it when hot, does it show signs of overly rich fuel mixture such as black smoke? If you don't pump the throttle pedal but hold it down to the floorboard steady and crank the engine over (allowing maximum air in) will it start that way? -Bah