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Powertour's avatar
Powertour
Explorer II
Sep 22, 2020

Onan 4000 MicroQuiet - Quasi No Start (new carb needed?)

Searched high and low & can't seem to find an answer to what I have going on.....

Generator came with my '15 RV. 160hrs on it, most before I bought it.

Plenty of spark. Plenty of fuel flow as tested with fuel line off carb & using prime function. New air filter and spark plug in it.

The thing will only start (hot or cold) if I drain the float bowl & crank it over with the float bowl screw open. Once it fires off I can close the float bowl drain screw & it will stay running.

Never seen anything like it in decades of off-road bike/quad carb'd stuff.

Float bowl stuck? Need a new carb?

Thanks in advance for
  • enblethen's avatar
    enblethen
    Nomad
    Sep 23, 2020
    No, it is time to remove the bowl, see if float is left in bowl or still attached to body with small pin.
    It is possible as other poster stated that debris could be in line or between needle and seat.
    You could carefully remove pin, float and needle. Spray brake clean or carb cleaner into opening. With needle removed, crank over genset to check for fuel flow into bowl.
    A good small engine (lawn mower) shop can go through carb.
  • Powertour's avatar
    Powertour
    Explorer II
    Sep 23, 2020
    enblethen wrote:
    Float could be stuck or needle has come loose from the float arm.


    If one of these is the case is it straight away new carb time?

    Thanks for the input!
  • 352's avatar
    352
    Explorer
    Sep 23, 2020
    Get some Sea Foam into the system. Give it a week. Try it. If it does not start give it another week. Great stuff.

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