1956 Fuel Pump/Carburetor problem

[highcking]

The dual action fuel pump on my 56 (feeding the Holley teapot) is not new but has seen little use. It has developed a strange quirk. If the car sits for a few weeks or more, the carb runs dry. I expect that so I prime it before trying to start. Generally works. Today I primed the carb multiple times and the car would run only on the priming gas, then quit. After a while I noticed that the clear-glass, in-line fuel filter was empty. I pulled the hose off the outlet side of the filter and sucked on it - yes, by mouth. In a few seconds gas burbled into the filter. I reconnected the hose and the car started and ran fine. Fuel filter shows gas bubbling through.

Shouldn’t the pump draw gas from the tank as efficiently as my mouth? Is the answer that a weak pump won’t draw fuel through a partially empty line?

bill in Luray

This page contains affiliate links for which I may be compensated. As an eBay Partner, and Amazon Associate I may be compensated if you make a purchase at no cost to you.

 

[74 Harley]

Yes, a good fuel pump should have no problem pulling fuel from the tank.
However I think you may be suffering from a sticky check valve. Try a can of BG-44 in the tank and see if that helps.
Or disassemble the fuel pump and manually clean the check valves.

 

[highcking]

I hadn't thought of that possibility. I'll go with the BG-44 first. I can also swap with another pump I have on the shelf. Thanks for pointing that out.

 

[paullb73]

Yes, a good fuel pump should have no problem pulling fuel from the tank.
However I think you may be suffering from a sticky check valve. Try a can of BG-44 in the tank and see if that helps.
Or disassemble the fuel pump and manually clean the check valves.

I have been having a similar problem with my 56 hard starting after sitting a few days . I have to pump the heck out of it to get it to start !

 

[Boozeman]

The dual action fuel pump on my 56 (feeding the Holley teapot) is not new but has seen little use. It has developed a strange quirk. If the car sits for a few weeks or more, the carb runs dry. I expect that so I prime it before trying to start. Generally works. Today I primed the carb multiple times and the car would run only on the priming gas, then quit. After a while I noticed that the clear-glass, in-line fuel filter was empty. I pulled the hose off the outlet side of the filter and sucked on it - yes, by mouth. In a few seconds gas burbled into the filter. I reconnected the hose and the car started and ran fine. Fuel filter shows gas bubbling through.

Shouldn’t the pump draw gas from the tank as efficiently as my mouth? Is the answer that a weak pump won’t draw fuel through a partially empty line?

bill in Luray

CASCO sells a small check valve you can install on your fuel pump to prevent the fuel from draining back into the tank: https://www.classictbird.com/Check-Valve-Fuel-Line-Fuel-Pump/productinfo/9160CV/

 

[dustinp]

I had a similar issue on my '56, and even after replacing the mechanical pump twice(first one defective right out of the box), it still persisted. Adding an inline electric pump to the fuel line solved the issue. With the electric pump turned on, I watch the fuel bowl fill up, and shortly after that you can hear a change in the sound of the pump as the fuel bowl in the carb fills up too. At that point, one full pump of the accelerator pedal sets the choke, and it usually will start on the second turn of the engine once the starter is engaged.

 

[DiIanni]

Thank you for the information. It is somewhat strange how after owning and driving the car for 20+- years, I all of a sudden should have to install an electric fuel pump. Please don't get me wrong. I will, in all probability install an electric pump.