The hole in the bottom of the pump well is the discharge hole and does not use a check ball. Fuel travels from the pump well out the discharge hole to the main discharge hole. The intake of fuel is fed through the cutout on the side of the pump well.
There are 2 small passages that feed the main discharge to the venturi. Be sure they are very clear. The main discharge uses a check weight. It’s simply a weight with a pointed end. When the pump is being pressed, the pressure lifts up the check weight slightly letting in the fuel.
The pump well should be polished with crocus cloth. Today’s fuel doesn’t have much lubrication, which means the pump cup is susceptible to damage when the wall is rough. No return spring under the accelerator pump. The spring on the throttle body does the job instead. There is a delayer spring that goes over the pump. This facilitates the pump when moving down.
How to test the accelerator pump circuit:
Adjusting Accelerator Pump Travel