Rebuilt Thermoquad issue -- It has to be primed before start each time

I did a test:
I manually filled the pump well with fuel, then the pump circuit works and I could pump it and make fuel squirt out of the two nozzles in the primary.

Then I did the test again filling the pump well and the corresponding bowl and put the two parts of the carb together, I could once again pump it and make fuel come out of the nozzles in the primary. However after a few pumps it ran out of fuel.

Then I filled the bowl only and did not manually fill the accelerator pump well. This time nothing happened when I pumped it. No fuel came out of the nozzles in the primaries.

Then I removed the brass disc with a ball and replaced it with the original one that came with the carb. (I had changed this part with the new one that came in the kit). I then filled the bowl and put the two parts of the carb together, tried pumping it and it worked??? :realcrazy: WTF?

The rebuild kit is form HYGRADE and seems good, the Orings are actaully Xrings which apparently cheap rebuild kits dont provide. When inspecting the non functioning brass disc it looks perfect and is identical with the original, it also performs identically when you test the valve with your mouth. Still have to assemble and test it on the car but it seems that the original disc allows fuel to enter the accelerator pump bowl whereas the new one did not.?