I agree there can be other issues or problems that contribute to vapor lock, certainly higher under hood temps will make the problem worse.
The OP Says it ran good .....but....on the hottest day this problem started. Classic vapor lock ..........in my opinion.
Sorry........ vapor lock has been an issue for 50 years ( for ever) and still present today and is made worse by the available fuel. If the winter grade fuel is used makes it far worse.
Just like carburetor icing problem exist and were not fixed for many years.
As for vapor lock happens to any engine, motorcycle are well known for the gas to boil in tank on hot days idling with low air flow over the tank.
Read all the links a lot can be learned. Jalopy Journal seems to understand the issue and the fixes or modifications.
Last edited by showkey; 06/22/2016 1:46 PM.
