[Tom Wells]

Dan,

Gasoline with alcohol seems to start vaporizing (not actually boiling) at about 140 degrees F. So the carb bowls don't need to get very hot to cause problems.

Without alcohol the onset of vaporization seems to move up to the 170-180 degree F area. A lot depends on brand, mix, quality, phase of the moon...

I'd try the suggestion above regarding non-alcoholic gasoline first to see if it helps.

Then there's always the switch to EFI to get the pressure up from 6-8 psi to 43.5 psi which raises the boiling point and can, in most systems return any excess to the fuel tank. Problem solved - at least that's what I went to after years of trying to beat the underhood heat related flooding.

Wells's corollary states that as the chemical substance laughingly known as gasoline gets crappier, the vaporization temperature goes down. And down.

Tom