The Stovebolt Site Forums The Shop Area Engine Shop Fuel pump woes

My '57 3800 has been sitting since last summer. Charged the battery and tried to start it but not getting fuel to the carb. It has a dual action fuel pump that is 4 or 5 yrs old. Couldn't find any blockages so I ordered a new fuel pump. I believe the brand is Airtex and it's identical to the one I took off. Tried again and same situation. It will start from priming but not getting fuel to keep running. I've checked all the lines and drained 4 or 5 gallons out the bottom of the tank to make sure there are no blockages. The gas is a mixture of last years and some new but it will start when priming with the same gas that I drained out. I can pull gas all the way to the pump with a little vacuum pump used for bleeding brakes. I won't be able to work on it again for a couple weeks but my next attempt will be to hook a small tank to the line at the back of the cab and elevate the tank a little to help gas get to the fuel pump. Hoping it will hold it's prime after I get the system full of gas. Any suggestions? I have an electric pump I can put on it if necessary but I'm trying to avoid that if possible. Thanks for any help.

Jeff

You didn’t say if you tested the pump for output. Pull the line at the carb and put the end in a can. Crank for 10 seconds and if it’s pumping there should be a 1/2 cup or so of fuel in the container. Get a AC Delco pump if yours is bad.

Yes, I disconnected fuel line at carb and also at fuel pump outlet and got nothing. The in-line filter in front of the pump is not getting any gas in it either.

RockAuto has ACdelco $48.

Put a hose from pump input fitting into a can of gas sitting on the ground and see what happens at pump output fitting. (Take off the filter and run another hose directly from output fitting into another container/can). Then you will just be testing the pump and nothing else. If it pumps, then it's something before or after the pump. Then hook up the carb end and see if it starts. No filter. New hose.

I tried two new ones from AirTex and they both leaked both oil and gas. Pretty sad I think.

Its possible the lobe on the cam is worn out.
George

Is your tank behind the seat? If so, you may have an air leak at the fitting at the top of the tank. It will suck air and prevent good/any fuel flow.
After you pulled gas with the vacuum pump, did the gas continue to flow on its own? If not, recheck the fitting at the top of the tank. Once you start the flow with the vacuum pump, gas should flow continuously via siphon action. A leak in that fitting will break the siphon.
Carl

Attach a vacuum gauge to the fuel pump inlet fitting and crank the engine. The pump should develop around 10" of vacuum and hold it for several seconds after the cranking stops. On the output side, test for pressure- - - -2 to 4 PSI is normal, and that should also hold for a short time when the cranking stops. If the pump tests good, look for a restricted inlet line, or a hole that leaks air.
Jerry