The Stovebolt Site Forums The Shop Area Engine Shop fuel pump not pumping

My 235 6 on my 55 2nd suddenly stopped working. this has been a complete frame off rebuild and I have a new double action fuel pump. The engine will fire off if primed but there is no fuel pumping. I checked all the fuel lines (they are all new) and everything up to the engine is clear. I've been driving the truck on and off for probably a couple of hours so the sudden failure is weird.

Question: Does the vacuum inlit on the pump need to be blocked off if not in use?
Any suggestions on how the pump could fail? I was going to open it up and see if perhaps something got stuck in there.

A fuel pump has two check valves in it, dirt under either can cause it to not pump.

Try removing the fuel line from the carb and blowing back through it to the fuel pump, if you can then both check valves are stuck open.

Then briefly crank the engine while holding a thumb over the fuel line, if you get no pressure and nothing more than a dribble of fuel the pump/valves are bad.

next try forcing air into the inlet of the fuel pump to blow it out, still with the line disconnected from the carb. Occasionally this will dislodge whatever was sticking the valves and you're good to go.

You could remove and disassemble the fuel pump side of the pump and clean the check valves if no luck otherwise.

In the future either use a fuel pump with the filter bowl on top (my favorite) or an inline filter before the pump.

Grigg