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Bobbo's avatar
Bobbo
Explorer II
Oct 12, 2016

ONAN 4KYFA26100K won't stay running

I have an ONAN KY-FA/26100K generator that won't stay running.

I exercise it every month, and this is the first time since 2007 that it won't stay running.

The fuel tank is full.

The oil level is about 1/8 inch below full and WELL above the add mark.

It starts just fine, and the Progressive Industries EMS-HW30C deems the power fine and powers the breaker box. I turn on the A/C or the space heaters, and leave it. When I go back about 20 or 30 minutes later, the generator is not running.

Any ideas where to look?
  • After watching a couple of Youtube videos on changing the fuel filter, I ordered that Airtex fuel pump, a fuel filter, and an air filter. If I am going to go in there, I am replacing all of those parts. I am having them delivered to my daughter's house since I won't be home, but am replacing all 3 while I am in there next month. (I do have a set of TORX drivers.) Thanks for all of your help. I will post a followup after installing them.
  • j-d's avatar
    j-d
    Explorer II
    This Airtex on Amazon should replace your fuel pump if you decide that's what you want to try. If you search "onan 4ky fuel pump" on Amazon, you'll find several, including this Airtex and a Cummins-Onan branded one at $80-something. One of our OP's has a step-by step for changing it. You need a T-30 TORX Bit in addition to a few ordinary tools.
  • Unfortunately, I am leaving in 2 days for 4 weeks. It will be awhile before I can check anything else out.

    The fuel filter has never been changed, so I will get one and install it, while checking for air obstructions.

    After it died the first time (while running the A/C), I switched to the space heaters so I would not risk the A/C.

    The model number is what Winnebago put in the manual. The actual generator has 4KYFA26100K.

    PM sent to j-d

    Thanks guys. When I get back, I will let you know what I find.

    Bobbo
  • j-d's avatar
    j-d
    Explorer II
    I think your Model Number is missing a Leading *K* and doesn't have */* in it. Does the Tag on your Genny look like this?



    Here's the Owner Manual with Fault Codes. If it blinks *36* which is actually three blinks then six blinks, it probably ran out of gas. We've had a rash of fuel pump failures on these lately. $100 or so part from ONAN, about half that on Amazon.

    A few years ago, we lost a few 4KY's with lubrication failure from low oil. By the time ONAN got to Spec *K* the Oil Level Sender had been discontinued. Up to us to keep it full. They're splash lubed like a mower engine, so no Oil Pressure Switch.

    I have the Service Manual and Parts List for 4KY Spec K if that's what you actually have. Just PM me with your email id.
  • You need to stick around while it is running and see what is happening.

    The A/C is not a good test load to use when the power might be fluctuating a lot.

    If there is a fuel filter has it been changed lately ?
  • Maybe check carefully for obstructed cooling airflow due to leaves, mouse nests, milkweed fluff, or whatever.
  • Turn all your breakers off then see if it continues to run after the 20 minutes then one by one turn the Breakers on till the problem comes back that circuit is your problem

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