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Skiemele's avatar
Skiemele
Explorer
Jul 16, 2013

Onan Generator Problem Solved

My Onan 5500 Marquis Gold generator would run for about 20 minutes and then quit. I tried replacing the fuel filter without success. I then rigged a gas supply directly to the carb (threaded the old fuel filter into a plastic tank and gravity-fed fuel through a 1/4" hose from a step ladder beside the motor home). Continued to run fine. Apparently, the fuel pump would work until it over-heated and quit.

The fuel pump was an Onan #149-2620. The Airtex E11015 is a direct replacement. I could not find one locally so I ordered from Amazon for about $55. You will need a #30 Torx screwdriver to remove and install.

I also added a fuel shut-off valve before the fuel pump so that I can run the generator dry for storage.
Class A

8 Replies

  • Skiemele's avatar
    Skiemele
    Explorer
    Jul 22, 2013
    427435 wrote:
    Rustydog wrote:
    Ethanol softening the fuel pump diaphragms.


    Another cheap and inaccurate shot at E10. If the diaphragm was bad, it wouldn't have run for 20 minutes and probably wouldn't even have started.

    I also wonder if the fuel pump was really bad or the fuel line connections were sucking air after things warmed up. Replacing the fuel pump would have also dealt with the fuel line connections.


    I don't know why the pump was bad, but it was bad. I reinstalled the old pump while waiting for the replacement part and it continued to******out after working for a while. No problems with the new pump installed so I'm thinking that maybe the pump had a problem. I keep my fuel stabilized when the coach is not in regular use and store with as much non-ethanol gas as I can find nearby.
  • C-Leigh_Racing's avatar
    C-Leigh_Racing
    Explorer
    Jul 21, 2013
    Rustydog wrote:
    Ethanol softening the fuel pump diaphragms.


    Oh yes, but wait till the nay sayers get here to kick this around.

    They must be getting kick backs from the ethanol plants or something, trying to make folks that dont understand think its such a good thing.

    One of these days they'll wake up & realize its nothing but to fill some congressmans pockets.
    Neil
  • Rustydog's avatar
    Rustydog
    Explorer
    Jul 21, 2013
    427435 wrote:
    Rustydog wrote:
    Ethanol softening the fuel pump diaphragms.


    Another cheap and inaccurate shot at E10. If the diaphragm was bad, it wouldn't have run for 20 minutes and probably wouldn't even have started.

    I also wonder if the fuel pump was really bad or the fuel line connections were sucking air after things warmed up. Replacing the fuel pump would have also dealt with the fuel line connections.


    I don't intend to get into a battle with you but I see issues all the time in small engines and marine engines.
    I have an outboard on my bench due to phase separation problems.
    A friends outboard a couple of months ago with gel in all 3 carbs.
    The problems are when engines sit for long periods of time.
  • 427435's avatar
    427435
    Explorer
    Jul 21, 2013
    Rustydog wrote:
    Ethanol softening the fuel pump diaphragms.


    Another cheap and inaccurate shot at E10. If the diaphragm was bad, it wouldn't have run for 20 minutes and probably wouldn't even have started.

    I also wonder if the fuel pump was really bad or the fuel line connections were sucking air after things warmed up. Replacing the fuel pump would have also dealt with the fuel line connections.
  • WyoTraveler's avatar
    WyoTraveler
    Explorer
    Jul 16, 2013
    Thanks for posting info. I have an appointment on Thursday for Onan warranty repair. Onan factory & service mgr says it is fuel pump. Apparently Onan has had problems with them in hot weather. If the Onan one doesn't solve the problem I'll go to the Airtex. Thursday will be a hot day, about 97, so will give it good test.

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