Ever since we made the drive back from Nevada the fuel pump has been dropping pressure from 7.5 down to about 6 when I sit there idling and when the fuel starts getting heated up. We vapor locked a few times in Nevada and the pump seized up multiple times. Now back in Cali I haven't driven around enough to say it's doing the same thing but it's still dropping in pressure slightly. Today Bry did a few things to see what we can do about it .... A few things people on other forums pointed out is that the 3/8 line is too small for the pump, certainly dead heading against the regulator without a return setup isn't helping and since my fuel pump was at the level of the tank I'm sure that wasn't helping.... That's 3/8 brake line that Bry bended up to make sure fuel flow was going to be down, that it wasn't going to rub against anything and not touch the 9" axle housing which gets pretty hot...
3/8 line will certainly flow more than enough fuel for that little engine. BUT.. the bigger factor to consider is the amount of turns(too many 90's) and sharp edges(bulk head fittings can be bad for those) that the fuel is exposed to along its route to the carb. Cavitation and agitation of fluids will hurt total flow and volume just as it would in an exhaust system. also a quick FYI for you here. Those Holley pumps have given a lot of similar headaches to others in regard to heat issues even on a good day.. especially when there is no return setup. So, with that in mind I would be looking at either replacing that pump with an Aeromotive or Magnafuel of similar size and just run it as is already configured.. or set up the return to help cool things down a bit better. Ideally.. anything over about 120gph should have a proper return setup anyways. Good luck with it.
So Bry thinks we should be able to use his spare return line regulator to install it right after the fuel pump and see if that makes a difference.
If your 9" is getting that hot, then something's wrong there too. I'd be more concerned with the exhaust heat and the ambient air temperature in the desert than anything. I've had a 95 E150 van (roller EFI 351) vapor lock climbing up out of Boulder Canyon on a 120*F day.
