Fresh Water Pump Cycling Quickly

[THJeff]

This weekend I was connected to a fresh water hookup at a marina from the dock to the regulator on my boat's connection with the fresh water pump turned off. All worked well but when I disconnected to go back to using the fresh water pump it is now cycling quickly when the water runs: on for one second, off for one second. The pump usually would stay on a 3-5 seconds, then turn off 3-5 seconds only coming back on when pressure dropped. The on/off cycle is even faster when hot water is used (on/off/on/off very rapidly). Perhaps this is just coincidence that it happened after I disconnected from the direct water line and my pump is just going bad (it's the original, manufactured in 10/99). Is this what typically happens when the pump dying or is there some other issue I'm missing?

Location: Rochester Hills, MI/Bell Maer/Club Island
Boat: 2000 Sea Ray Sundancer 410
Engines: Caterpillar 3126 Diesels

 

[mwph]

It is quite possible that you introduced some air into the system during your connecting/use of the marina water system. Also possible is the introduction of some crud from the same use.

I say start with the easy stuff by removing, cleaning and replacing the screens at all of the water outlets and especially the one adjacent to the water pump itself. After that bleed the system of any air by simply filling up the tank & turning on all of the faucets. Hopefully you will see one of them sputter violently as the air is pushed out.

 

[THJeff]

Thanks, I'll check that out. By screens do you simply mean aerators? Because the water pressure is fine, it's just that the pump is needlessly cycling too frequently.