Forum Discussion

Bamarickandlisa's avatar
Oct 28, 2013

Need help with carb..

Onan 4000 MicroQuiet
Changed old carb with a new one because of surging.
New carb runs good, pulls microwave good, but when i turn the ac on, it chokes the generator down close to killing it.
Any Ideas ?
Thanks
  • I put a hard start capacitor on it .
    Filled the fuel tank all the way ( per manual )
    Turned every thing off while starting ac on.
    Checked linkage.
    Onan 4000 ran perfect.
    Ran my Honda 3000 and the ac still is ok.
    SO , I really don"t know what fixed it ...

    Thanks for all the reply"s.

    Rick
  • Check the amount of amperage on start up of the A/C. Also note what else is on when trying to start the A/C, convertor, water heater, refrigerator. You only have 33 amps available from the generator, water heater 6.5 amps, convertor 5-7 amps, refrigerator approx. 7.5 amps, plus lights and what ever else is on. You A/C will pull close to 20 amps on start up, leaving only 13-15 amps left.
  • If the new carb does the same thing as the old one it most lickly is not the carb. You should find out what's wrong with it before you try to fix it.
  • Does the governer open the throttle fully when the load is applied? Maybe you messed that up when you changed the carb.
  • I would put the original carb back on and take it in for service. The issue may be something other than the carb.
    The cause I can't say but it sounds like a lack of fuel with both carbs.
  • Does it recover?
    If so I would guess your new carb is lean?
    Why change carbs instead of servicing the other one?