Meh. Looks like there is. At least that's inferred here.
US EPA approves Florida, North Carolina requests to change summer gasoline RVP | S&P Global Platts
Not surprising. It's cheaper to make and sell making consumers happy and more profit.
Many states have their own requirements, some including 'drivability' requirements. Bet Fla is not one of them.
previous (2013) map here
Date of switch to summer-grade gasoline approaches - Today in Energy - U.S. Energy Information Administration (EIA)
Sounds like vapor lock on the suction side. Putting the line under pressure rather than suction should help alot.
When I've had that problem, it was also after idling and the worst was after stuck in traffic on interstate and a very warm spring day with winter blend.
I've added several layers of insulation and a shield to the lines back to the cross member. I also keep some 'storage fuel' on hand, which might happen to be in the gas tank when those conditions are present.
You prob won't need to do that with the pusher setup.
