AC fuel pump advice

[Lynn Eades]

Amongst us, most things have been covered. but here are a couple of other hints:
As Richard said, make sure the sight bowl seals properly or you will never get it working like it should. Sometimes the alloy is distorted.
Replace the seal around the diaphragm rod. It stops you sump filling with petrol if your diaphragm leaks. Make sure the drain hole to the outside is clear.
Some times the wear occurs at the pivot and you get lost motion. (your last picture, this is where part of the pump stays still while the other part is still moving)
What Andrew says is very important about tightening the screws. It restricts the delivery vol. (the spring dictates delivery pressure) The diaphragm must have enough material inside the pump to move freely, so activate the pump to its maximum travel and tighten the screws in this position.
I hope that helps.