I have a 1982 Ford F250 with the 7.5L motor. I recently got the vehicle and it had been sitting for about 5 years only ran a few times. I got it home (about 20miles) and then when I plated it, it ran like crap and wouldn't stay started. I rebuilt the carb, which greatly needed it and then it would start and only run for a min or so then die. I converted the fuel filter over to a see through one and after playing around with it realized I was not getting any fuel to the carb. Which I'm wondering if this is why it would only run for a few and then die out. Is it possible for both fuel pumps to go out at the same time? And is there any other things I should check before dropping the tanks and replacing them? This could get costly. I checked the fuse under the driver side and the fuel one was fine. Any input would be greatly appreciated.

treedoc

 

have you checked the relay? Assuming pumps are both electrical and not mechanical....lol... just answered my own question rereading your post. Yes electrical if in tank.

also while truck is running, will it stay running if 1/4 to half throttle on accelerator pedal?

 

Are you sure you have in-tank pumps? I didn't think the 82's had gone to that, but still had engine-mounted mechanical pumps. If you do have in-tank pumps there's been a lot of cussing and discussing the electrical feed to those pumps. So you should do a search on the forum for those threads.

If it has a mechanical pump, which I think it should unless it has been converted, then I'd bet the rubber fuel lines are rotted and allowing the pump to suck air. I had that problem on an 82, albeit w/a 351W, and it would start and run just fine in the driveway, but if you took it for a drive you were going to stall somewhere within the first 10 miles. I finally found that every single piece of rubber fuel line was bad: the one from the tank to the steel line; the one from the steel line to the switching valve; the one from the valve to the next line, and the one from the end of that line to the pump. On another truck, Dad's '81, the line was bad enough it would drip through the side of the line! It wasn't cracked, but just rotten to the point it leaked.

 

Yeah I was kind of surprised to read he may have electrical pumps myself.... but kind of hard to miss either way.... rebuilding a carb but not being able to see a mechanical pump? Good input though, Gary

 

I am wondering where he put the new fuel filter he installed. Did your truck have a filter looking thing before the carb with 3 lines going to it? Does it still have it? That would be a sign it has the electric pumps. I believe the mechanical pump system had an extra line coming off the mechanical pump itself.

 

Thanks guys for the input!

I did have the three way fuel filter at the front of the carb and I converted it to a plastic see through with rubber lines. Except the one that goes directly into the carb. It does not have a mechanical pump. The lines run under and directly to the transfer box and back into the tanks. I was playing around with it yesterday again after I got off here and got fuel running back into the carb from the front tank. It would fire though. So know Im looking at electrical issues. I did replace the coil, but not wires or distributor. Ill look under the cap and check the cap and rotor bug first. When it was running it sounded great through. Just couldn't keep it running for more than a min or so without choking out. It seemed like the bowl was emptying and not refilling. All the vacuum lines seem to be hooked back up where they belong and its pulling a really strong vacuum as well. Do pumps start to go bad and just get intermittent? or do they usually just die?

Thanks again guys!

 

Electrical pump then. It may well be running as you turn the key to Start, but then losing power when you release the key. That would probably fill the bowl and then let it run dry. There's a relay that is pulled in by oil pressure closing a switch, IIRC, and a problem in that circuit would do that. As said previously, that has been discussed thoroughly and you can find it via searching the forum.

 

I am not sure you can get rid of the 3 way filter thing. By the way it was not a filter, though I think it does have some sort of coarse screeen in it. That was the return orifice for the return system. Your real fuel filter should be screwed into the carb, so that needs to be checked.

I am not sure the electric pumps are made to be dead headed. In other words when the carb does not need any fuel(the bowls are full) the fuel flow will stop in your setup, and I do not know if the fuel pump is designed for that. Before with the 3 line orifice deal, fuel was always flowing back to the tank.