I have a 1987 swb with a rebuilt 2.6. The rebuild included a new fuel pump. Lately after driving about 30 or 40 minutes and letting the truck sit longer than 20 minutes, it will run about 10 or 20 seconds and die. I can crank the engine and it won't start. When I look at the fuel filter located just above the frame rail going to the carb, it is empty.I have pulled the pick-up tube and sending unit(the screen was perfectly clean) and blew out the fuel line. I can either restart by letting it sit a couple of hours or by priming the carb with fuel several times. The priming method usually takes two people, one to prime and one to keep working the throttle. Is this classic "vapor lock"? Do I need to install an electric fuel pump? My other Raider ran for 246,000 miles and never once did this and this is the carb from it.

Oh,also ,it only seems to happen when the outside temp is above 85 degrees.

Run it until it dies like it's been doing, then as soon as it dies crack open the fuel filler cap and see if you have a lot of suction occurring.

I'm wondering if maybe your pump isn't pulling fuel because of a vacuum being created in the tank as it runs. If so, maybe fuel return might be clogged? I'm just guessing here...never had to 'shoot that problem but I'm thinking it's a possibility. Maybe Frank or FE will chime-in here.

EDIT: Oh, and is your exhaust in good order? Might it be blowing hot exhaust on your tank?

bowl vent valve...if this is clogged then it will cause vapor lock.

I think the exhaust is in good order but I will check it out. I have opened the gas cap and no vaccuum sound but it was after sitting for a little while so I may not be doing it soon enough.I will try and open it sooner next time, also I will check my Chiltons to find the bowl vent and check that too.... thanks for the ideas.