Forum Discussion

dunedawg's avatar
dunedawg
Explorer
Jul 30, 2013

Onan Marquis Gold 5500 shuts down after 20 minutes

I have a 2007 Weekend Warrior trailer with an Onan Marquis Gold 5500 gas generator. As I've seen posted in the past, mine will run for about 20 minutes, then shuts down. It shows a 36 error code (gas related). I've had it at the Cummings repair shop 4 times now (yes, Onan generators are made by Cummings), and have thus far spent over $600.00 to no avail. They've replaced the circuit board, drained the gas tank and bolied it out and tested the fuel lines, replaced all filters, changed the oil and it still keeps shutting off. They keep telling me they've checked the carb and altitude sensor, and it is not the problem. Does anyone have any advise?
Toy Haulers
  • mjayco's avatar
    mjayco
    Explorer
    Jul 30, 2013
    My 4000 went thru 2 fuel pumps in the first 20 hours under waranty.
  • nayther's avatar
    nayther
    Explorer
    Jul 30, 2013
    Another fuel pump check is to get a gas can next to the generator and drop a hose in it connected to the fuel pump and see if it runs better/longer. If it still drops off try putting the gas can up on a chair or table so that it is even with the pump, less work to "lift" the fuel. If that makes a difference I'd double check the fuel line and replace the pump.
  • thedan's avatar
    thedan
    Explorer
    Jul 30, 2013
    Mine did the same thing. You know it is not the carb, it is getting fuel. You can remove and ground out a plug once it does not start to see if it does have spark. I am also pretty sure it is the fuel pump. Easy to replace.



    justALnow wrote:
    Sure sounds like fuel pump to me. I have the same gen, same year and that's what mine did.

    Fuel pump gets hot and shuts down, cools off and it will run again, then shut off again when it heats up.


    Simple test - when it shuts down, hit the prime button and listen for the pump. If it's not running, that's your problem.
  • BobWanderer's avatar
    BobWanderer
    Explorer
    Jul 30, 2013
    mustangglp wrote:
    I would ck the vent for the gas tank? Take the gas cap off and see if it still does it.


    that is a good start, another idea would be, let it run until it stalls and immediately try to restart it, if it won't start, use some starting fluid (after you remove the air filter), if it runs for a second or so, its a fuel problem. Go easy on the starting fluid, I overdid it one time and she backfired and burnt the hair off my arm.
  • Bedlam's avatar
    Bedlam
    Moderator
    Jul 30, 2013
    The oil pressure switch could also be failing at operating temperature resulting in a shut down.
  • Y-Guy's avatar
    Y-Guy
    Moderator
    Jul 30, 2013
    Here are a few threads, not sure if you've read these or not.

    thread 1
    thread 2

    If you google, "onan shuts down rv.net" you'll find a number of threads about this, sorry I didn't find a solution but might me something on those threads that you haven't tried yet that might help.
  • justALnow's avatar
    justALnow
    Explorer
    Jul 30, 2013
    Sure sounds like fuel pump to me. I have the same gen, same year and that's what mine did.

    Fuel pump gets hot and shuts down, cools off and it will run again, then shut off again when it heats up.


    Simple test - when it shuts down, hit the prime button and listen for the pump. If it's not running, that's your problem.
  • mustangglp's avatar
    mustangglp
    Explorer
    Jul 30, 2013
    I would ck the vent for the gas tank? Take the gas cap off and see if it still does it.

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