Jon might join in here and help straighten us out but I’ll give it a try till he corrects me.
Your pump draws fuel past the ball check into the pump well on the up stroke. On the down stroke the plunger seats the ball check and fuel is forced up the passage to the pump outlet ball check and spring unseating the ball and fuel is then passed through the smaller passage next to the discharge well and up to the crossbar where it is discharged into the venturi cluster. You may not be able to see this. The early ‘B’ carbs had a discharge nozzle that sprayed the fuel directly into the air horn out side of the cluster so it is easy to see.
If you replaced the pump without removing the outlet spring and check there may blockage at this point. If that is open then you need to clear the circuit up to the crossbar.
Denny Graham
Sandwich, IL

Denny G
Sandwich, IL