Car wont restart after sitting for 5min ???

Problem: car initially starts and runs fine, however when it sits ((errands)) even for 5 min it wont turn back on crank , crank ,crank?? Could this be related to the carburetor? Heat? Rich/lean? Or?
Has anyone experienced this or have some insight.
Same thing happened to me.
Car started fine when the engine was cold, get it hot would not restart no matter what I did.
Replaced ignition box, all is good.