Jeffrey, the ball in the waste(clack) valve must move for the pump to work. The ball is glass in my pump. At rest, the ball sits in a frame that, from memory, has limited adjustment up and down. With flow in the drive pipe, the ball lifts and seals against thick rubber with a centre hole in the top of the chamber. The sudden stop of flow down the drive pipe causes the "clack". The ball drops, flow resumes and the cycle repeats.
Sometimes the ball would hold up against the rubber with a trickle of water coming out of the top hole. Finger pressure was enough to force the ball down to start the flow in the drive pipe and the pump cycle.
I suggest you remove the flanged plate, lift out the thick rubber and check the clearance of the ball. It sems to me that the ball supporting frame is too high.
Hope this helps.