fuel pump or carb rebuild

[heyharris1]

1986 c30, if it sits for more than a couple days you have to pour a small amount of fuel to get it to start, otherwise it just cranks like its out of gas, after doing this, adding a little bit of fuel directly to the carb acouple times it will fire up and stay running, and as long as it gets started every day it will fire right up, but anymore than a couple days and it seems like its out of gas, also it has a 4 barrel carb and mechanical fuel pump. there is 2 tanks, could the second tank be causing the problems.
thank you

[VileZambonie]

Pull the hose off of the outlet of the pump and put it in a container. Crank the engine for 15 sec and see how much fuel you get.

[78 Chevyrado]

It might be the diaphram in the fuel pump.  My 78 did that when i first got it and what it turned out to be was a leaking diaphram.  It would let the fuel go back to the tank and suck the fuel bowl in the carb dry.  It would start just like you said by pouring gas in it, I replaced the pump and it fixed it. 

[heyharris1]

tomorrow looks like its a trip to auto parts store for new pump, i priced them today for 15 bucks new, so why take a chance
thank you

[hilton850]

I agree...probably the fuel pump.  I had this problem also, but not as bad since I never had to dump gas in the carburator.  On my truck it turned out to be a little check valve assembly (I think) in the carb.  I wound up tearing the carburator apart and cleaning every part to cure it...for what it's worth.  I also run an edelbrock carb so if you still have the Q-jet this probably doesn't apply.

[heyharris1]

yes, its still the Q-jet, when i took it out, fuel was comming out of one of the very small holes near the top, im thinking some kinda vent, but my quess is the diaphram is bad and thats what let the fuel come out of the little hole, its ok easy fix, being i bought the truck real cheap i will probably tear the carb apart and clean it up just to check things out.
thank you