water pump replacement

[Paradise II]

I have a 1985 carver 3697 mariner. Water pump wont shut off. Going to try one more time to bleed all the air out and if that doesn't work figuring the pressure switch is bad and will replace the pump. For a guy that is a C on the mechanically inclined scale is this something that can be done. Thanks in advance for any thoughts.

Paradise II

[bud37]

A bit more info that might help.....What kind of pump is it ( fresh water system),did it work fine before.... is it pumping water now and just not shutting off, or not pumping at all.

If the latter, try tapping the pump when on, where the lines go in and out and see if switch is stuck.

[Viper]

You either have a bad plumbing leak, or your tank is empty, or a pressure switch issue, or the check valve in the pump has failed. Most pumps have rebuild kits available, and replacement switches. Does the system pressurize, do you get full water flow when you open a faucet?

[km1125]

Does it build any pressure? If so, then after the pump is run for a while, turn it off. Let the water system sit for about an hour then open a faucet and see if you still have pressure. This will tell you if the check valve in the pump is failing. Could be just a piece of debris. You could take it apart and clean it. You might find one of the diaphragms has a hole, and as Viper said, there are a lot of replacement parts available for them.

Even if you just elect to buy a new pump and replace it (which is pretty easy), then take the old one apart and see if you can find out what went wrong. If you break it, so what? You've already replaced it but it would be a nice learning experience.

[Paradise II]

Yes pumping good. Just wont Shut off. Yes i still have pressure after shutting it off and it sits just cant remember How much. Will do more testing this weekend. Thanks for the help.

[mjk1040]

Sounds like the pressure switch is shot in the pump. If you decide to replace the pump instead of rebuilding it, make sure you get the same gph pump.

[Rich W]

Had same problem with my fresh water pump. After looking for leaks and finding none, I got out the manual for the pump where they suggested pulling the outlet pipe off the pump and install a plug then try the pump again. I did this to find it would not shut off and went out and got a new one. The POs had removed the inline filter so I added a new one with the install. Since old pump was not that old I was thinking that perhaps there was some debris keeping the thing from shutting off. Will be opening up the old pump to see and hopefully replace parts/clean so I can have a backup pump for the future.

Happy Memorial Day!!