Anybody experience this generator issue?

Discussion in 'Electrical Stuff' started by Russ Calasant, Aug 6, 2017.

  1. Russ Calasant

    Russ Calasant Active Member GOLD Sponsor

    Dec 9, 2009
    East Greenwich, RI
    2001 480 DB
    CAT 3196
    Following 5 days of gen running non stop we left a mooring and headed out in good size seas, 5-7ft. I soon noticed my gen shut down and the SR monitor was alarming. After returning to the dock and checking the issue, the temp gauge indicated overheating, the strainer had some blockage but still flowing, checked all hoses. Found the impeller was shredded. Maybe lost suction and she ran dry? Is that possible? Thoughts?
  2. PlayDate

    PlayDate Active Member SILVER Sponsor

    Dec 25, 2006
    Washington DC
    1994 370 Express Cruiser
    454 Mercruisers
    When was the last time you replaced the impeller? It doesn't take long to shred an impeller if you lost water flow. Congrats on solving the electrical problems.
  3. Quint4

    Quint4 Active Member TECHNICAL Contributor SILVER Sponsor

    Oct 6, 2006
    S.W. Ohio
    330 Sport Bridge
    5.7 MPI 350 Merc Bluewaters
    Perhaps the impeller was on its last leg and your "run dry" theory is correct.
    May have been all it needed to finish it off.
    Have you replaced it and all is back to normal?
  4. dwna1a

    dwna1a Active Member GOLD Sponsor

    Apr 23, 2012
    James River
    88 Weekender 300 "Seahorse"
    Twins 350
    When you figure it out I'd love to know as well. My Port engine did the same thing this weekend. She ran great going out then suddenly no more water flow. I had shredded the impeller. It was only 1 year old
  5. NotHerDecision

    NotHerDecision Member PLATINUM Sponsor GOLD Sponsor

    Jun 28, 2016
    Houston, Texas
    2001 Sea Ray 460 Sundancer
    2014 Seadoo 155 LTD
    2105 Seadoo 130 SE
    Cummins 6CTA 8.3L
    If it runs dry it will shred the impeller. I say clean the strainer and make sure you have good flow(open the strainer and seacock) then replace the impeller and try again. Good thing the impellers are inexpensive!
  6. juggernaut1

    juggernaut1 Member PLATINUM Sponsor

    Apr 19, 2015
    Perth, Western Australia
    2006 38 Sundancer
    8.1S / ZF 63V Drives
    I had a major blockage on a mooring last summer's holidays whilst on a trip. Seaweed had been sucked up and was backed up against the hose nipple entering the strainer i.e. it didn't even make into the strainer. There was vastly reduced flow but the impellor was cactus. Luckily I had a spare and could change it in short time. I now keep two spare impellors on board.

    B BARKER Member

    Apr 20, 2014
    I just went through an ordeal a couple of weeks ago and mine quit pumping water and I caught it in time, my strainer was clean but I wasn't getting any water flow so I started at the source. Turned off tru-hull took hose off turned tru-hull back on and nothing ? Poked a phillips screw driver into tru-hull and all kind of leaves came out of it then the water started flying everywhere, it was stopped up all the way not a drop was coming out till I jabbed that screw driver in it !!!!
  8. electricaldoctor

    electricaldoctor Active Member TECHNICAL Contributor PLATINUM Sponsor

    May 14, 2008
    Thousand Islands, Rockport, Ontario.
    1988 390 EC
    454 Mercruiser Gassers
    When your impeller fails, your temperature will rise to the point where a sensor will shut down the generator.
  9. cwiert

    cwiert Member SILVER Sponsor

    May 7, 2008
    Westbrook, CT
    1998 400 Sedan Bridge
    CAT 3116 - 350HP
    Hey Russ,

    Last Sunday was nasty out there on LI Sound. My dock neighbor was saying that his props came out of the water a few times. Granted, he has a smaller boat than yours (a 34'). It might be a long shot, but do you think maybe with the rough seas you got an air lock when your were coming home in that slop with the genny running? My money is on the sea conditions causing the issue. Either the intake thru-hull came out of the water or maybe lots of bubbles under the boat caused it to loose suction/prime and then the impeller ran without water until it was shredded.

    That's all I got for theories. Good luck.
  10. northern

    northern Active Member

    Jan 17, 2007
    West coast Vancouver to Alaska
    380 Aft Cabin 1989 GPS and Charts by Nobeltec
    Twin 454 strait shaft
    Some times that happens to us. Our problem is seaweed. I have had main engines plug but mostly the generator. The way we clean it is remove the hose to the inlet of the strainer. Force a garden hose into the hose. I have one size for main engines and one for generator. I secure it with a rad clamp then connect the hose to the boat potable water system then turn on the hose. It cleans the inlet in the hull.

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