Onan Generator running rough

[notch78]

I have an ONAN 5500 HGJAB generator that when started after sitting for over 24 hours runs very rough for a couple minutes. It will eventually start running smooth but something is not right and I would like to fix the problem before it ruins a trip and dies while I'm camping. I have read it can be the choke assembly but how do I figure that out and can I buy just the choke assembly or would I need to buy an entire carb?

[koda55]

Is your choke operating properly? Sounds like it might need to be adjusted or cleaned.

[Veebyes]

Double post

[Veebyes]

i5trucker wrote:
Have you done the easy stuff, like air filter and spark plug, yet?

More easy stuff: fuel filter? drain carb?

Most engines like plenty of clean air & clean fuel first & foremost.

[Bobbo]

Sounds like it runs rough till it warms up. Sounds normal to me, mine does it. Until it gets to operating temperature, the fuel doesn't vaporize properly. If it is only a couple of minutes, and it happens every time you start the generator when it is cold, I think it is just the nature of the beast.

[onemilmhz]

Back when I had the TH (Keystone Raptor) with the Onan I was constantly having to change the fuel filter. It was so problematic that I ultimately quit using it altogether and eventually ended up selling the rig for a myriad of reasons, including the crappy genset. I have had better luck with a $199 Harbor Freight generator.

[Golden_HVAC]

It might be that after sitting a few months, there is gunk in the carburetor and it is just dirty.

How long have you run the generator at one time? Do you put a load on it - like a 1,500 watt electric heater or the A/C unit? That will help pass more gasoline through the carburetor, and will help to clean it - load it up and run it for a hour.

How long has it been since the last oil change and cleaning the air filter?

Good luck,

Fred.

[i5trucker]

Have you done the easy stuff, like air filter and spark plug, yet?