How much fuel should a fuel pump pump if a fuel pump should pump fuel? How to I check volume of fuel?

Truck has never started on it's own since I took ownership and I don't know the history of it before that as the owner had passed.

The check balls are in the correct position and are new. The pump discharge did not seem to seal well so I hammered it down in the hole with a brass punch until it seemed to seal better.

I checked both float level (1 5/16) and float drop (1 3/4)