Fresh water pump

Discussion in 'General Discussion' started by DougLas, May 21, 2019.

  1. DougLas

    DougLas Member PLATINUM Sponsor

    481
    Dec 13, 2008
    Lake Erie
    39 Express
    454
    1990 39 Sea Ray Express. Boat was winterized for the winter by the marina. When launching the boat it was found that the port side fresh water pump is seized up to the point the belt flipped over. Has this happened to anyone else? This just happened today have not found out any more.
     
  2. hottoddie

    hottoddie Well-Known Member

    Jan 11, 2012
    Boston/Cape Cod
    1986 Sea Ray 390 EC
    Garmin 4212 Chartplotter
    Garmin 24 HD Radar
    Garmin 546s Plotter
    454 Crusaders
    I assume you are referring to the "sea water pump" that draws in the outside cooling water. Yes they can and do fail. Be thankful it's the port side as it is the easier of the 2 to access. How long since the impellers have been changed?
     
  3. JVM225

    JVM225 Well-Known Member GOLD Sponsor

    Apr 8, 2008
    Farmingdale, NY
    2002 410 Sundancer, Monaco Edition.
    3126 Cats.
    Are you talking about a pump mounted on the engine run by a belt?
    If so, there are two.
    One is a circulator pump (called a water pump in cars) that circulates coolant through your engine and the other is a raw water pump that brings raw water in to the boat to your cooling system.
    Since the title says “fresh water pump” and in the text you referred to “port side fresh water pump” I’m going to assume that it is the circulator pump and that your motor is “fresh water cooled” (uses anti-freeze).
    While the marina would have winterized the raw water side of the cooling system (raw water pump) there would be no need to winterize the fresh water side because it is filled with antifreeze.
    The circulator pump that circulates the antifreeze is not serviceable. The main part that fails on them is the bearing inside of them. A leak at the shaft the pulley rides on is usually the first sign that it is failing, but it’s also possible that an old bearing in the pump could have frozen.
    If it is the raw water pump, they can fail too. It could quite possibly have had a small raw water leak and after sitting all winter the leak could have caused rust to form and the pump to seize.
     
  4. DougLas

    DougLas Member PLATINUM Sponsor

    481
    Dec 13, 2008
    Lake Erie
    39 Express
    454
    The system is a open cooling where the water that is taken in from the outside water source is circulated through the motor. Some refer to the pump as a freshwater pump other reference it as raw water pump. After talking with the service techs I have been informed that the impellers on the raw water pumps now only last for around three years.
    What has happen: The impellers have came apart and in turn locked up the pump. Further findings the impellers can lose their shape after a few years and pump less amount of volume of water needed to cool the motor under power.
    Why are these problems happening? Lower quality products.
     
  5. BAC.94

    BAC.94 New Member

    20
    Aug 6, 2018
    Indiana
    2003 320 Sundancer
    Twin 6.2's with v-drives

    So Saturday the boat fired up and we headed out. After spending a few hours at anchor, went to leave and the starboard engine would not start. Limped back in on one engine in a heavy wind (that was NO fun). Got the motor started in the slip finally and the belt started screaming. Top pulleys were turning but belt wasn't. I ended up cutting the belt off and trying to turn everything thing by hand. Discovered the raw water pulley wont budge. Would a bad impeller cause this or would it be more likely the shaft bearings?
     
  6. JVM225

    JVM225 Well-Known Member GOLD Sponsor

    Apr 8, 2008
    Farmingdale, NY
    2002 410 Sundancer, Monaco Edition.
    3126 Cats.
    We’ve got a shallow sandy bottom around here so it’s best to change the impellers in the raw water pumps at least every other year and when I had twin Alpha drives in my old boat I would change those little impellers every year just to be safe.
    You might be able to get away with 3 years where you boat because of different conditions but I wouldn’t chance it around here.
    The other thing you need to worry about with impellers is them burning out if you pick up some kind of a blockage that prevents them from pulling in water. Even just a temporary blockage can damage them. Those things are spinning fast and need water flow to keep them lubricated. Plastic bags and eel grass are the most common hazards around here making “South Bay Strainers” a must have.
     
  7. JVM225

    JVM225 Well-Known Member GOLD Sponsor

    Apr 8, 2008
    Farmingdale, NY
    2002 410 Sundancer, Monaco Edition.
    3126 Cats.
    Could be either. Start with pulling out the old impeller and see if that frees it up.
    You might get lucky.
    Could be there is a piece of impeller broken off in there.
    If the impeller is broken apart, try to get all missing pieces out of the system.
     
    BAC.94 likes this.
  8. Sublimetime

    Sublimetime Active Member

    673
    Oct 22, 2007
    clifton nj
    420 da
    454
    its very important what JVM said above. When you remove the impeller, if it is not intact you have to find all the pieces and reconstruct the impeller to be sure you have them all, probably pieces up against the trans cooler.
     
    BAC.94 likes this.

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