FRESH WATER PUMP

[PAUL T.]

Greetings and Happy holidays to all.... My question is..... My fresh water pump won't cycle off, there does not appear to be a blockage as it will pump water. it is the original 1988 2.8 gpm shureflow..... any suggestions on the best replacement. Also I did check the diaphrams and sensor switch..... nothing obviously wrong. Thanks in advance for your help.......PAUL

[Ray & Sandy Erps]

Our pump runs a little funny when we suck one tank dry then switch to the other tank.  The pump seems sensitive to a little air in the system.  I've tee-d my salt water foot pump to the fresh water system and use that to work most of the air out of the system when switching tanks, then turn on the faucet and just let it run for a little while to get the rest out.  That works for us.  

I've also had a small leak at one of the inlet ports on the pump, so it was sucking air there for awhile too.  Drove me nuts.  Kept taking it apart, greasing up the o-ring with vaseline for a quick fix while out for the weekend.  Finally bought new port/o-ring assembly at a boat supply store.  Parts were cheap (surprisingly) and the fact that the store had them in stock made me think it was a common problem.  I carry a spare set now and the pump works great.

[sselinger]

My guess is that the sensor switch has gone bad. I have had very good luck with the Shur (both on my 27 and 34) pumps and would suggest that you replace it with the same model or upgrade if you want more capacity.

Steve Selinger
Aquila #1047

[Ken Juul]

If the pump is pumping but not shutting off the pump is not sensing a pressure build up.  Either the pressure switch is bad or you have a leak pumping water into the bilge.

[ejryan]

Here's another possibility.  If you have an in line filter on the suction side of the pump, check to see that it isn't partially clogged.  I've had a similar situation, and while it still pumped water, it could not draw enough to build up the required pressure to shut off the pump. However, when it started to cycle on and off without reason a few months later, I replaced the pump since it was a 1989 didn't make sense to try to keep it alive any longer.  (FYI - I replaced the 2.8 Shurflo with an "identical" pump, but the mounting holes had changed.  Never as easy as you might hope.)