You might want to look into this link from Steel Soilders, if might give you som information. Sounds like it might be a check ball issue installed wrong, or you may have got a wrong rebuild kit . . .  https://www.steelsoldiers.com/threads/m38a1-carburetor-nightmare.198285/ 

Gents, working on an m38A1, bought a carb kit and a fuel pump kit from Walcks,I'm not good with carbs so I gave that to a friend who runs a local garage to rebuild, I installed it.  Rebuilt the fuel pump this past week and installed. 

When I prime the pump I get fuel through the fuel line to the carb, but the engine does not fire.  When I shoot starter fluid into the intake the engine fires, so not an ignition problem.  Any thoughts on whats happening?  It seems I'm not getting fuel to the cylinders.

This is an older M38A1 as it has the fording system installed on the vaccum pump.

Eric if this thread needs to go elsewhere please forward.

Todd Gabrielson