Onan generator shutdown

Discussion in 'General Maintenance/Repair Questions' started by Jeanne Marie, Aug 10, 2018.

  1. Jeanne Marie

    Jeanne Marie New Member

    3
    Aug 10, 2018
    Searay sedan bridge 52
    Cummins
    I am writing as a new member in order to perhaps offer help to anyone who may have had a similar experience with their onan generator. I purchases a Searay sedan bridge 52 in May in preparation for a trip from Florida up the east coast. I had the engines and Genset serviced before leaving. The onan generator started right up and about 4 hours later died while under way. I got a 36 code, non specific shutdown. It would not restart until it sat for awhile. The next day it started up again and died in a few hours. This continued all the way up the coast. In Charleston I had it looked at and it ran like a top. I scoured the internet for possible causes. A couple of weeks ago it died again while under way and this time I went below and opened the bleed screw and air was present in the line. After bleeding it started again and each time it died I found air in the fuel line between the lift pump and the injector pump and each time it restarted after bleeding. An attempt was made to search for a fuel line leak and none were found. It turns out that the lift pump, as it got hot and weaker, could not keep up with the injector pump, and a negative pressure caused bubbles to form, thus shutting the engine down. A new lift pump cured the problem and now it runs like a top again.
     
    gerryb, Jaybeaux and bajturner like this.
  2. Sea Gull

    Sea Gull Well-Known Member

    Oct 19, 2006
    CT
    2015 L650 Fly #509
    CAT C-18, 1,150 HP
    Good info! Thanks for posting.
     
  3. Mac Magic

    Mac Magic New Member

    19
    Jun 7, 2018
    Jupiter, FL
    '05 500 Sedan Bridge, 7212 Garmins
    QSM 11's
    that's interesting. i'm kind of having the same issue. generator runs great, then shuts down.

    but I'm getting the code of 1 blink, then 6 blinks which isn't in the manual.....
     
  4. Havana Shamrock

    Havana Shamrock Well-Known Member SILVER Sponsor

    Sep 9, 2008
    Long Island.
    2005 500DB
    QSM11's,
    Honda 30HP
    Sea Doo 90 HP H.O.
    I have changed the lift pump,Racor,and supply line from the transfer valve and still mine shuts down after 4 hours there’s really nothing else left to check.
     
  5. Jeanne Marie

    Jeanne Marie New Member

    3
    Aug 10, 2018
    Searay sedan bridge 52
    Cummins
    When the codes don’t make sense it might be the control board. That’s an expensive repair
     
  6. Mac Magic

    Mac Magic New Member

    19
    Jun 7, 2018
    Jupiter, FL
    '05 500 Sedan Bridge, 7212 Garmins
    QSM 11's
    well that doesn't sound positive, but it is shutting down for a reason and i'm determined to figure out why
     
  7. Keith Zibilich

    Keith Zibilich Member SILVER Sponsor

    33
    Nov 7, 2016
    New Orleans
    2008 Sea Ray 470 Sedan Bridge, Raymarine Axiom
    Cummins QSC 600
    Jeanne, I assume you have a fuel selector that you can draw from either port or starboard tank? A buddy on mine had a similar problem and discovered it was an issue with the fuel line at the tank being partially clogged. He switched to the opposite tank and everything works fine. Just a thought.
     
  8. Jeanne Marie

    Jeanne Marie New Member

    3
    Aug 10, 2018
    Searay sedan bridge 52
    Cummins
    Well as in all good stories the plot thickens. After replacing the lift pump in Charleston the Genset ran like a top for the next 50 hours and then the same symptoms recurred. The Genset would start and then shut down after several hours. When I returned home to Cape Coral I called the local Cummins Service Center and the technician said the pump was bad again. His first concern was that it seemed to be drawing better from the starboard tank but when he switched the selector switches to the port tank the pump got very quiet. He initially thought that the fuel draw from port tank might be clogged but when he blew air through it there was no impediment to fuel flow. But when he tried to blow air into the fuel return line on the port tank there was an obstruction. He discovered that when the boat was manufactured in 2007, the fuel return hose to the port tank was caught between the bottom fiberglass mold and the top fiberglass mold. He took pictures showing the hose pinched between the two thus there has never been any return to the port tank. So the fuel pump would work its little heart out trying to get fuel to flow and it eventually failed, probably time after time since the prior owner I am sure had a similar problem. This time, in addition to a new fuel pump it has a new fuel return line and once again it seems to be running like a top.
     

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