I recently purchased a 1987 sailboat and the owners were not using freshwater system saying it would not prime. I have filled the 50 gallon bow tank, opened all faucets to expel water
in lines so far, no change. The original Johnson P5 type pump
is running but not building pressure. I removed intake hose from pump
and jetted water
back towards tank hoping to remove any air pockets. I also jetted water down the output side and had flowing water from all faucets and shower
both hot and cold. I added a lot of water on the output side thinking I need to insure hot water heater
is full of water with no air pocket. I also jetted water through water pump
from intake side to output side and got a lot of scale deposits out of it. I have allowed the pump to run many times with no change. Any suggestions other than time for a new pump maybe? Thanks for any input!