Help on fixing a vapor lock!!!

This gives some idea of the temperatures pump fuels evaporate over.
From a published test with the distillation points I plotted a non-reformulated gasoline from 2007, and one from that time with 8% ethanol.

fuel-distillation-2007-png.png

Read the graph like this:
Find a temperature on the left. Take 150* F. Follow the line across to the Chevron Premium, and then go straight down to the bottom axis. For 150*F, we see about 7% of this fuel evaporated. While the same 150* F caused 30% of the other fuel to evaporate. Big Difference!
Neither of them fully boil off until over 400*F.

Also notice the shape of the E8. This is a problem with a lot of the RFG pump fuels. The light portion vaporizes easily, but then there is a jump to the mid range and completion. This disrupts the flame front in a relative cold cylinder.