Rebuilt my Rochester 'B' carb, which is actually a very simple rebuild, but I'm stumped with an issue.....It will not start unless gas is poured down the carb, then in order to keep it running, poorly I might add, I need to pump the gas pedal rapidly....It will stall if I stop pumping the pedal.....Now as best as I can figure there's a blockage symptom of gas not getting to the main jet, and the only way its running is from the accelerator pump drawing gas down the carb....I took the carb off twice disassembled it, and did not find anywhere where there was a blockage.... The power valve tower was perfectly clean, as with the screen & jet.....Is there somewhere else I should be looking at ?