Freshwater pump runs continuously

Discussion in 'General Maintenance/Repair Questions' started by R-and-R, Oct 9, 2018.

  1. R-and-R

    R-and-R Member SILVER Sponsor

    45
    May 9, 2018
    2002 340 Sundancer
    8.1S Mercruiser
    2002 340DA

    Went to the boat today and turned on my freshwater breaker.
    Pump began running continuously and did not stop. I didn't find any leaks, and my tank level did not drop at all.

    I'm guessing I have a pressure switch/sensor stuck?
    Can it be repaired/replaced? Or am I looking at whole new pump?
     
  2. Matt Powless

    Matt Powless New Member

    1
    Oct 9, 2018
    1999 310 Sundancer
    350 Mercruiser w/V-Drives
    If your pump is similar to mine there should be a removable filter right before the pump. Check that if you haven't already done that. We have had that issue in the past on our 1999 Sundancer.
     
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  3. LUnaCY

    LUnaCY Member

    61
    Aug 28, 2018
    Afton, MN
    310 Sundancer 2002. Mercruiser 5.0 MPI Bravo III
    Mercruiser 5.0 MPI Bravo III
    Ive had mine run continuously after running empty and filling. I turned it off for a few minutes then back on and let it run. Eventually it self primed. Might be a better way to get it primed.
     
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  4. importmonkey

    importmonkey Opinionated Member

    925
    Jul 9, 2015
    Middle River, MD
    2007 44 Sundancer
    QSC 500s
    Could be an air pocket. Open all outlets (hot and cold and toilets) one at a time and see if any sputter (spitting air). Once all the air is out, it will be able to build pressure.

    Could also be stuck pressure switch on pump.
     
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  5. R-and-R

    R-and-R Member SILVER Sponsor

    45
    May 9, 2018
    2002 340 Sundancer
    8.1S Mercruiser
    How do I become an "Opinionated Member" ? :)
     
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  6. techmitch

    techmitch Well-Known Member SILVER Sponsor

    May 1, 2008
    Chesapeake Bay, Middle River/Frog Mortar Creek MD.
    1999 270 DA
    Twin 4.3s W/Alpa I Gen II's
    That's something you've got earn. Lol
     
  7. R-and-R

    R-and-R Member SILVER Sponsor

    45
    May 9, 2018
    2002 340 Sundancer
    8.1S Mercruiser
    So, I checked the intake filter and that looked good.
    Then I opened each faucet, got a few burps of air.
    After I closed them all, the pump shut off.
    Not sure how air got into the system, maybe switching back and forth with city water?

    Anyway, problem resolved.

    Thanks everyone!
     
    importmonkey likes this.
  8. Little Ducky

    Little Ducky Well-Known Member

    Jun 5, 2017
    Chattanooga TN/Dickson TN
    1998 SeaRay 290 Sundancer
    Twin EFI 5.0L w/Alpha 1 drives
    Depending on the type of pump you have...... the pump can come apart and you can change out various components as they wear out. Last year I just replaced the entire head on the original 1998 pump to get it working again. It was actually cheaper then buying individual components and way cheaper then buying a new pump. All you need is the pumps part number which is on the motor and you can search to find your parts.

    Glad you got it working again but it might be a tell tale sign that the diaphragms are getting a little hard.
     
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  9. R-and-R

    R-and-R Member SILVER Sponsor

    45
    May 9, 2018
    2002 340 Sundancer
    8.1S Mercruiser
    Sounds like another punch list item for winter.

    Thanks for the tip!
     

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