Fresh water system question.

• May 17, 2021

• #1

redlightning

Active Member

Dec 26, 2016

108

Beaver Lake Arkansas

Boat Info

2012 390EC

Engines

8.2l

Should I expect the fresh water system to remain pressurized? So when I leave the boat and return the next day and turn on the fresh water pump it has to pump for 6-8 seconds to pressurize the system. I am not seeing water anywhere indicating a leak.

 

• May 17, 2021

• #2

hughespat57

Well-Known Member

GOLD Sponsor

Sep 25, 2016

1,254

Rock Hill, SC

Boat Info

300 Sundancer 1994, trailered tri-axle LoadRite roller

Engines

Mercruiser 5.7 260HP Alpha One Gen II, twin

As long as you see no water, likely just losing pressure back thru the pump to the tank.

 

• May 17, 2021

• #3

Korkie

Active Member

Feb 2, 2016

1,331

Leonardtown, MD Potomac River / Chesapeake Bay

Boat Info

2006 340 Sundancer, Garmin 7610, xHD 24 Radar, VV703, SeaStar Hydraulic Steer, Shadow Drive AP

Engines

Mercruiser 496 Mags
Bravo III Drives

Check real good for water, it can hide. As highspat57 said, no water -no leak. Another way to conform it is to leave it on while at the boat and do not run anything. If you hear it cycle, you have a leak somewhere. You can also turn off all the fresh water tree valves and isolate the pump to see if you are getting back flow.

 

• May 17, 2021

• #4

E

ErikE

Well-Known Member

Dec 26, 2020

453

Northern Michigan

Boat Info

1986 Sea Ray 340 SD

Engines

Twin 454

I am having a similar issue that my pump runs often without water being used. Is there a backflow prevent valve near the pump typically to stop water from leaking back to the tank? Would make sense.

 

• May 18, 2021

• #5

markrsimon

Active Member

Sep 1, 2018

419

Cleveland, OH

Boat Info

92 Searay 400 Express

Engines

7.4L Mercruiser Gen V

Normally there are two check valves. One built into the freshwater pump, and the other built into the dockside water connector. If your losing pressure over time, as others have stated - something is leaking. A fitting, a faucet, or perhaps the checkvalve is bleeding back a bit. If there is no water evident anywhere - then it almost has to be the one built into the freshwater pump.