How to Diagnose Vapor Lock in a Corvair
If you have been driving down a road for a considerable time and engine is hot and you suddenly glide to a halt, as if you have no gas, and yet you do, you may have this condition.
When the engine compartment temp is hot enough to turn the fuel in the pump and lines into vapor, the gas vapor expands pushing the fuel left in the lines back into the tank. Thus, your car is only running on the little fuel in the carburetor bowl area, which is not much. Once used, you stop and must wait until the engine cools off enough for it not to happen.
However, it also happens frequently after the car has been parked between 10-30 minutes on a hot day in the sun. The reason for this is because today’s gas contains more alcohol which has a lower boiling point than the gas of the 1960s. Corvair engines run hot, hence the issue to be aware of.
The ONLY thing a corvair owner can do is to install an electric fuel pump inside their gas tank or near it. It is not necessary to remove the mechanical fuel pump. Connect the electric pump to the fuse box under the dash at the radio terminal for 1960-66, and at the IGN Fused one for 67-69.