Next time you encounter this problem, remove the wire from the coil. If it then turns over freely, you've confirmed the timing is too far advanced and/or your starter is not strong enough to run an agressive initial advance.

Easy pie!

 

That's a good idea, if the problem goes away it's ignition, if it persists it's starter(or possibly electrical).

 

 

possibly vaporlocking?

 

That's why I said to have a phenolic spacer under the carb and to make sure the fuel lines are away from the engine heat. Timing should be between 6 and 10 degrees BTDC. Mine runs great at 10 degrees using 87 octane and runs cool as a cucumber.

 

Had same trouble with another vehicle I had....Starter gets overheated...had to start vehicle with a crow bar accross the solenoid. Works ever time!!

 

Using a crowbar or a screwdriver to connect the positive points on the solenoid (starter relay) has noting to do with a hot starter. If that works for you, then you need to go upstream to the starter switch itself.

 

Yes you are heat soaking your starter. I would recommend either wrapping our headers or putting a heatshield on your starter. Should take are of your problem.

 

That would be true if it turned over, and just didn't catch. I read that it would not turn over at all, or very slowly. That has nothing to do with vapor lock.

 

I once had this same problem with a recently rebuiltengine that ran too hot, it was like it almost seized whenever I shut it down. The bad news is that it did eventually overheat and seize. My mechanic friend beleived that the pistons (rings) were too big for the bore which caused too much friction and unusually high compression. This would be an obvious machining error.Has yours been rebuilt recently? If so check the compression. When you start up does it warm up quicker than normal? When you shut it off does it wind down a bit or stop abruptly as soon as you turn the key?
I hope that your problem is less severe than mine was. Good Luck!