Every carb kit I buy for a Rochester does not have the recharge check ball retainer pressed into the pump/plunger far enough(this is on the very bottom of the plunger). This allows the ball to fall to far down/away from it's seat. Gas flowing past the ball sucks it UP against it's seat on the pump stroke. If the ball is to far away from the seat the gas just flows by it. In that case it flows back into the bowl not to the nozzle.
It is a little hard to see but there are four slots in the bottom of the plunger. If you look between the slots you will see the recharge ball. With the plunger held in the upright position you will see the ball is down from the seat. the correct clearance between the ball and the seat should be about .020". On most replacement plungers the clearance is more like .060".
I put the accelerator plunger in my vice and push the retainer further into the plunger. There is a stop so you can't go to far.
This always works for me.

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