Hi, had a brief overheat the other day. Stripped the pump, gave it a good clean and reinstalled. Got very little to no water at low revs. Ordered and installed a service kit as I've no idea when it was last done. Diaphram, valves and springs looked ok but changed any way. Problem persists. Valve seats look ok in the pump but not sure everything is seating right. When I blow back through the engine via the manifold water injection pipe I get clear unrestricted flow out to the seacock. I get that these plastic valves aren't gonna be air tight but feels like zero resistance. Any Sabb engineers out there with any advice?