Fresh Water Pump Wont Stop Running

K

Kramerah

New Member
Aug 27, 2015
4
Louisville
Boat Info
1988 340EC
Engines
454 Mercruiser Inboards
Hello I have a 1988 Sea Ray 340 Express Cruiser. This spring when I flushed out my fresh water system and filled up the tank I noticed that my pump kept running after I shut all the faucets. I opened a faucet and after a few seconds the pump had a different sound to it. I shut the faucet and the pump built pressure and shut off like normal. A few hours later the pump came back on and ran and would not shut off. I did the same thing with the faucet and got it to shut off again. Now every time I flush the toilet or use only a small amount of water the pump will not go off. I thought there may be air in the lines so I started at the farthest outlet and worked my way back until I thought all the air was out. I ran about 2 full tanks through the system trying to bleed it thinking there could be an air pocket somewhere in the lines. When the tank is completely full the system works properly, however when I use just a small amount of water and the tank is not completely full I keep getting the problem with the pump running and not shutting off. I cannot locate a leak in the system. Could there be a problem with my pickup tube? Has anyone had this type problem before.
 
Could be a couple of things. How old is the pump? They do wear out. One of mine failed due to an air leak inside the pump. There was a kit to rebuild it, but I just replaced the pump since it was old and not that expensive. You could have a bad shut off switch and possibly a hose leak on the fittings that go into or out of the pump. Check for leaks with some soapy water and see if you get some extra bubbles somewhere. That will help you decide what to do to fix it.
 
I just had the same problem a few weeks ago. Our boats are from a different era but installation may be similar.

My Fresh Water Pumps are Shurflo Blaster II. They have a built in pressure switch. Once pressure is achieved, it is supposed to shut off. I contacted the manufacturer Pentair Flow Technologies and received the following recommendations:

"First thing to check are for leaks in your system , if no leaks are found sometimes a simple switch adjustment will shut off the pump, - on top of your pump you will see the pump switch held down by 4 screws in the center you will see the adjustment screw you will adjust the screw a quarter of a turn counter clock. If the pump doesn’t shut off after you try this then you would need to replace the pump switch."

In my case, the suggestion didn’t work. I then tapped on it and it shut off. Since the problem was recurring and I did’t want to have to do this on a regular basis. I then ordered (only sold through distribution) and changed out the switch with recommended replacement (~$75) and two hours of labor.

Absolute waste of time, no improvement. It turns out that the old pump was losing suction or prime.

Brand new pump ordered and installed by Marine Max (one of my better experiences with them) for $458. Problem solved.
 
Last edited:
Bumping this old thread, the '97 we just bought..this issue was revealed during the survey so we accepted troubleshooting it and taking it on ourselves. So we currently have the SureFlo 3.0 gph 12v MFG# 4138-111-E65
She "mostly" stays running when water pump switch is on. Once in a blue moon shuts off ..not often though. Turning on a sink faucet usually results in quite the sputter and spurts of water...a nice flow quickly settles down to more of a medium trickle at best. And the pump runs and runs and runs.
Look at the pump under the deck hatch, some visible air in that clear bulb which I'm guessing is a screen filter of sorts. Seems to be from the water "source" line side of the pump...has that 90* white elbow and then the line runs down and aft. (see pic). MFG date on lower right corner of label is 12/96, and since boat is a '97 I'll bet a pint of Guinness she's an original pump. I see Defender has a sale now, 95 bucks, may as well go for a replacement. First I want to check that clear diaphragm/filter looking piece just before that white elbow.
WaterPump.jpg

Yesterday we ran the sink until the fresh water tank went empty, filled it, put in some H2O treatment to help kill the skunk smelling water, going to empty it again. What appears to be a little sand sometimes comes out of the sink faucet.
 
No idea what pressure a pump puts out. We have had the pressure switch fail on our pump twice. Once when we were 4 days away from parts. I hot wired the pump to fun when powered. We would turn it on for 15 seconds then off and run on the accumulator bottle. I do not think the water pump is rated for continuous use. It might over heat and catch fire. Buy a complete new pump. It is only the price of 1/4 tank of fuel.
 
YeOldeStonecat said:
Bumping this old thread, the '97 we just bought..this issue was revealed during the survey so we accepted troubleshooting it and taking it on ourselves. So we currently have the SureFlo 3.0 gph 12v MFG# 4138-111-E65
She "mostly" stays running when water pump switch is on. Once in a blue moon shuts off ..not often though. Turning on a sink faucet usually results in quite the sputter and spurts of water...a nice flow quickly settles down to more of a medium trickle at best. And the pump runs and runs and runs.
Look at the pump under the deck hatch, some visible air in that clear bulb which I'm guessing is a screen filter of sorts. Seems to be from the water "source" line side of the pump...has that 90* white elbow and then the line runs down and aft. (see pic). MFG date on lower right corner of label is 12/96, and since boat is a '97 I'll bet a pint of Guinness she's an original pump. I see Defender has a sale now, 95 bucks, may as well go for a replacement. First I want to check that clear diaphragm/filter looking piece just before that white elbow.
View attachment 57401
Yesterday we ran the sink until the fresh water tank went empty, filled it, put in some H2O treatment to help kill the skunk smelling water, going to empty it again. What appears to be a little sand sometimes comes out of the sink faucet.
Click to expand...
The clear part contains a stainless filter screen . Unscrew it to remove and clean the screen . Add a 1/4 cup of bleach to the tank 3/4 full so there is room for the water to slosh around In the tank go for a bit of a ride to agitate the tank . Run the pump to empty it clean the filter again and refill the tank and you should be good to go with no more sedimentciming through
 
Handsome Transom said:
The clear part contains a stainless filter screen . Unscrew it to remove and clean the screen .
Click to expand...

That clear part with the filter...looking at it it sure looked like it could be "hand unscrewed"...appeared to be two tabs that you'd just push with your fingers. But today was the worst of a 3 day heatwave we had, my slimy wet bare hands couldn't get a grip. Will go back with tools Wednesday.
 
northern said:
We would turn it on for 15 seconds then off and run on the accumulator bottle. I do not think the water pump is rated for continuous use. It might over heat and catch fire. Buy a complete new pump. It is only the price of 1/4 tank of fuel.
Click to expand...

Agree about not wanting to run it continuously...
I need to find where this "accumulator bottle is"...found a few threads here and other forums about some bladder inside that starts leaking.
 
YeOldeStonecat said:
That clear part with the filter...looking at it it sure looked like it could be "hand unscrewed"...appeared to be two tabs that you'd just push with your fingers. But today was the worst of a 3 day heatwave we had, my slimy wet bare hands couldn't get a grip. Will go back with tools Wednesday.
Click to expand...
Definitely start with cleaning the filter. I had similar spurting issue at the beginning of the season and found the screen was full of crud. Also check the screens on your faucets as well as they will have build up also.
 
If once you purge the air from the output side, the pump stops running-on, until the next time you open a faucet, it sounds like a problem on the tank side. Check all fittings from the tank to the pump. a "leak" on that side almost never shows up as water leaking out. Rather air is getting sucked in, but only when the pump runs. It could be a cracked pickup tube inside the tank. In that scenario,, there would be no problem until the tank level dropped below the level of the crack.
 
I Recently Had to replace my water pump as well on my 2004 Sea Ray 300. I bought the Shurflo Aqua King II Standard, and it was pretty easy to replace. I also got a new line filter. Well after installing it, it kicked right on and I purged all the water lines, but the pump kept running. So I let it run for about 30 mins to see if it would cut off, it didn't. I proceeded to check for leaks, and didn't find any. So then I tried cutting off the Inlet distributor that pushes water through out the boat, That way the pump would only need to pressurize one small 18" hose. Well the pump still kept running. So I called Shurflo today and they suggested adjusting the pressure valve with a 5/64 Alan wrench next to the main switch. Im going to try that this weekend and let you know if that works. If that doesn't work I may have a bad pump, either way super frustrating. The only other test I know to try is inserting the inlet side into a separate source of water to draw from and if the pump stops then, I know I may have a leak on my pickup inside the fresh water tank.
IMG_3883.JPG
 
Yesterday we ran the sink until the fresh water tank went empty, filled it, put in some H2O treatment to help kill the skunk smelling water, going to empty it again. What appears to be a little sand sometimes comes out of the sink faucet.[/QUOTE]

You might pick up handfuls of replacement connectors as I have replaced over 80% of mine and carry the additional 20% on board... 15mm & 22mm.
 
We chased pump issues for a while, when our boat was new. Not constant running, but intermittent and annoying. The culprit turned out to be the water heater’s pressure relief valve. This was hard to find because the “leak” was just going into the grey water sump where there is always water anyway.
 
Gonna clean up that area this weekend. This week I took apart the filter..it was about 50% covered in brown slime 'n grit. Rinsed that all good...put it back together. Pump still runs steady..but at least this time, I don't see air in that clear filter cover like I saw before.
New pump going in this weekend, a local place had 'em on sale..$93 bucks for a new SureFlo. About 45 bucks for the pump rebuild kit, figure for not much more may as well get a whole new pump, it's 21 years old!
 
I just replaced mine, and instead of the 3GPM version, I went with the 5GPM model. Nice having a little more pressure, and the fittings are all the same. A little more expensive, but if the Admiral has a happy shower, it's worth it.
 
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