Question about Watts Onan Portable Generator - 4000 , Model# 5500

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I have an ONAN Microquiet 4000, 6 years old, ca 500h on the meter and not run for about 6 month, stored in hot climate (Nicaragua) When started the Onan was initially surging for a few minutes, then engine stopped. Engine will crank normally but will not start again. Batterie ok, Oil ok, Sparks ok, drained gas from the carb and replaced with fresh gas. Any advice? Many thanks!! email:

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  • ulibartke Sep 30, 2010

    oil is fresh, changed the spark plug, engine does not start

  • ulibartke Sep 30, 2010

    spark plug is new, new oil, but engine does not start...

  • ulibartke Sep 30, 2010

    spark plug is new, new oil, but engine does not start...

  • ulibartke Oct 02, 2010

    your suggestion worked out just fine. One of the little channels was blocked and I could clean it with cleaner and a little mechanical help. Generator runs well now! Thank you very much!!
    Enjoyed the experience.

  • ulibartke Oct 02, 2010

    your suggestions worked very well! Generator is running now like new. Thank you very much!!



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Remove the float bowl and the fuel solenoid from the bottom of the carburetor. In the area where the solenoid screws into there is a jet. Most likely there is debris in the jet orifice. You cn use a small nail or a scribe to GENLTY scrape in the throat area of the jet to clear any obstructions. Then spray carb cleaner into the jet orifice area as a final cleaning procedure. Before you re-install the float bowl also remove the fuel supply hose from the carb and spray carb cleaner from the float needle area back to the supply connection. You may have to remove the float pivot pin but, I would not remove it unless your absolutely sure that there is debris in the float valve needle area. Getting ready to install the float bowl.... spray the plunger of the fuel solenoid with carb cleaner. Once your sure that the fuel supply passages are clear install the float bowl and solenoid. Then connect the main fuel line and test the generator.

There is one more thing you can check but you have to be real careful. That is checking fuel supply during engine cranking with the fuel hose removed. (FIRE DANGER) There should be good fuel flow via that fuel tank, fuel pump and fuel filter during cranking. If you don't have good fuel flow with the fuel supply hose removed from the carb, the problem can be debris in the bottom of the fuel tank, a clogged fuel filter or a bad fuel pump.

Thanks for choosing FixYa.


Posted on Sep 30, 2010

  • Kelly
    Kelly Oct 02, 2010

    I am happy your up and going again. There is nothing that makes my day like someone fixing a problem that otherwise could have ended up in a shop when the owner could have fixed it. Time effort and money saved for the owner = a good day here. Take care. Kelly


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Try to chage the engene oil..and replace the spark plug of your generator......

Posted on Sep 30, 2010


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