I am having a problem with the fresh water not pumping unless the tank is completely full. I think it is losing prime and had always been hard to get it primed, it seems that the tank is lower than the pump. If I fill it all the way with some extra pressure from the garden hose, it will work fine for a while and pumps a strong spray. I will get it working before a trip and it will work fine for a while then just stops. Any ideas? It is not leaking anywhere and the tank is mostly full when it quits. When it is not working I do not hear the pump running, but not sure it is supposed to. Possibly a bad self priming pump? This one has had me scratching my head for a while now.