# Rough Running Champion



## pursang (Oct 3, 2016)

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 ?


----------



## aandpdan (Oct 8, 2012)

The carburetor is likely dirty. It could be from bad gas.

You could try a fuel system cleaner but you'll probably end up cleaning or replacing the carb.


----------



## RonJ (Aug 5, 2015)

Has it been sitting up with gas in it? In the meantime, put some SeaFoam in and let it run for awhile, maybe that will be the easiest fix going.


----------



## exmar (Jun 29, 2015)

Whenever I'm given a small engine powered machine which "runs rough," I first put a lot of seafoam in and let it run and run. A lot of times that cleans out the fuel circuits. Fall back is clean/rebuild/replace carb.

Do you keep StaBil or equivalent in the gas in the unit? If you don't, it's a self inflicted injury. The ethanol in all the gas we buy is the culprit.


----------



## pursang (Oct 3, 2016)

Thanks for all the replies, I'll pull the carb off tomorrow and see what I find.


----------



## pursang (Oct 3, 2016)

Problem still persists after cleaning the carb.


----------



## dwt (Sep 25, 2016)

Did you clean the carb? My first guess would be a clogged idle circuit. Basically, it can't idle and the governor is kicking up the throttle to keep it from stalling.


----------



## pursang (Oct 3, 2016)

dwt said:


> Did you clean the carb? My first guess would be a clogged idle circuit. Basically, it can't idle and the governor is kicking up the throttle to keep it from stalling.


Yes, main jet, idle jet and main nozzle are all spotless, I didn't notice anything obvious blocking the jets but the float bowl did have a small amount of crud, not bad though for an 8 year old machine.


----------



## Handyhiker (Sep 29, 2016)

I could not tell for sure, but make sure your throttle return spring is attached and snug. This is the spring that is around the rod that goes from the carb to the governor. It it breaks, mine did, or becomes loose, it will act like this. You can pull some through and just re bend it.


----------



## aandpdan (Oct 8, 2012)

That crud is the problem. You could put the carb in an ultrasonic cleaner for a while. It's not just the jet, but the small passages in the carb that clog.

Failing that, replace the carb. It may not be that expensive.


----------



## pursang (Oct 3, 2016)

I finally got around to fixing the problem, I removed the black plastic plug located under the idle screw and cleaned the idle jet, as you can see in the video the lever for the govener above the pull starter is now steady and the engine is running smooth again.


----------



## iowagold (Jan 22, 2020)

cool.
also see the carb clean and ultrasonic pages
click here for the ultrasonic page

the corked idle air jet is a common issue on all gens.
run seafoam and stabil in the fuel.
seafoam all of the time to keep it clean
stabil in the stored fuel. i use 2x the amount and have been at 5 to 10 years on gas storage!
click here for the fuel additive page.

and if you can avoid ethanol in your gen fuel.


----------



## Airstreamer67 (Oct 3, 2020)

Good job on getting that genset running again!

I've ruined enough small-engine carbs in my life, especially since ethanol has been forced upon us, that I no longer store any gasoline generators with fuel in them. Instead, I pump out the tank, run the generator until it dies from lack of remaining fuel, drain the fuel bowl (Honda provides a convenient screw just for this purpose), and store the unit in the warmest and driest place I can find. Since doing this, I haven't had a problem. Although I haven't measured it, I don't think it takes more than 15 minutes for me to fill the tank, crank it a bit until the fuel reaches everywhere it needs to be, and then it's off to the races. 

I do use Stabil, but only when it's not practical to execute the above procedure.


----------



## speedy2019 (Jan 29, 2019)

I dont empty anything on my gen I just make sure I run my gen monthly for 10mins or so and have fuel stabilizer in the tank. Also I store mine at the side of the house so its just ready to go, with a thick breathable weather proof cover on.


----------



## pursang (Oct 3, 2016)

My routine is to turn the fuel tap off and let the engine die, next time I swap out the gas I'm switching to ethanol free gas.


----------



## drmerdp (Apr 10, 2018)

90% of the time the pilot jet is the culprit. Small orifice and direct access to open air.


----------



## Sbmcbilly (Jul 22, 2021)

Ok. Mine dies the same thing. New carb, new petcock and new sparkplug.


----------



## LaSwamp (Mar 16, 2021)

Sbmcbilly said:


> Ok. Mine dies the same thing. New carb, new petcock and new sparkplug.


Fresh gas? 

Surging almost always means an issue with the fuel. I once got a new carb for a B&S engine and it was still causing surging. I had to take it apart, clean, and reassemble it since I don't think it was assembled correctly and there were obstructions somewhere. Also, check to make sure the air filter isn't clogged. That will also cause a surging condition.


----------

