Champion Running Rough

I have the same generator. Never had a problem. I never shut it off with the switch. I just turn off the gas and let it run till it runs out or gas. I also have a fuel filter that I added.

pursang wrote:
My Champion 4000/3000 Model C46535 only has about 30hrs on it and ran perfect out of the box, these days it's been running rough or surging when the choke is fully open, it'll smooth right out with the choke at the halfway position but I'd like to get it back to running right with the choke off, any ideas on why this is happening ?

I watched the video. The engine is running lean. When you shut some of the air off it runs fine. It is in the carburator. Their is a jet or passage stopped up or partially stopped up. I would say take the carburator off and apart and give it a good cleaning. On my generator I go to the local air port and buy around 5 gallons of av gas. Then I take a gas can and fill it with half unleaded and half av gas. You don't want to run a 4cycle engine on pure av gas. But you can run a 2 cycle engine on pure av gas. I have not had any problems with gas going bad. When Hurricane Ike came through in 2008. My generator was running on 2 year old gas. You do need to run them every so often so when you need them . They will work right.

What WN said, took me twice to get it right on my Champ.

Since then I have taken to always drain the gas out of the carb.

Doesn't yours have a drain on the bottom of the carb?

Surging and smoothing out on half choke means not enough fuel,

You need to clean the carb again, particularly the main jet. There's still something blocked.

It took me two tries on my Honda 2000 when it was doing the same.

Call the Champion tech support line.

I use Stabil Marine or Enzime in any gas I bring home for the small engines the Enzime get rid of the water in the ethanol gas, I think I will start do as my friends and neighbors do and start using non-ethanol gas in my small engines and tractor it is worth the extra expense.

Problem still persists after cleaning the carb.
https://youtu.be/P1z2OpgFJ54

2oldman wrote:

pursang wrote:
any ideas on why this is happening ?

How long has it been sitting with gas in it?

I just replaced the gas recently so probably only sitting for a few months.

These portable generators like to be run on a monthly basis if possible. I try to do this, and add Stabil to the gas as well for any that may remain in the carb, etc even though I tend to run the gas out of it.

Sure sounds like a gunked up carb, a heavy dose of Seafoam in the fuel & let run awhile then shut down and let sit for a day then run again. May have to run a couple of times but that is the best way I know of.