Generator starts but backfires.

[WNYBill]

I have a Champion 4000 watt generator. Hasn't been run in a year, was running fine but may have had ethanol gas in it. With the choke on it starts, but when you flip the choke off it backfires and quits. Won't rev up and run smoothly. I gave it a shot of ether with the same result. I am thinking a stuck valve or ethanol crap in the carb. I am going to drain the gas and replace with ethanol free and drain the carburetor. Then pull the sparkplug and flood with a 50/50 mix of ATF and acetone. Anything else I should try?

 

[TerryfromSWIowa]

If it starts and dies why would you flood with the mix. It is a carb issue. Clean the carb.

 

[miangus]

I would drain the carb it may have just enough water in the bottom to plug the jet. Replace gas and give the gas a dose of Sea Foam, start and run with the choke on. However, removing the carb and running it through a sonic cleaner will fix the issue.

 

[jimg.allentown]

Your main jet is probably plugged. Take the float bowl off, and run a piece of fine wire up through the jet orifice. It is above the part that holds the bowl on.

 

[Jack345]

Your main jet is probably plugged. Take the float bowl off, and run a piece of fine wire up through the jet orifice. It is above the part that holds the bowl on.

Right on.

 

[scootergmc]

Unless there's more you're not telling us, you left gas in it- ethanol or no it can all degrade and create problems. Clean your intake and clean the carb.

Install a t in the fuel line and drain the tank and run it dry when you know it's going to be sitting.

 

[WNYBill]

I usually turn the fuel off and run it dry, but this time I lent it to my grandson, and I think he put ethanol gas in it and didn't run it dry.

I am draining the tank right now and will drain the carb, it has a plug on the bottom. I'll put fresh ethanol free gas and a little seafoam in it and see if that solves the problem without tearing into the carb. The plug was wet but looked OK. I blew it dry.

 

[WNYBill]

Put it back together. Fresh fuel with seafoam added. Let the fuel run through the carb. Closed the carb plug and it starts on the first pull with choke on, tries to run but still backfires through the carb and quits. I can keep it running with the choke on and feathered but it continues to backfire through the carb when I open the choke and then quits. I am letting it sit, hoping the seafoam cleans the carb. Is there anything I could spray into the carb that would clean it?

 

[scootergmc]

Clean the carb.

 

[buickanddeere]

I usually turn the fuel off and run it dry, but this time I lent it to my grandson, and I think he put ethanol gas in it and didn't run it dry.

I am draining the tank right now and will drain the carb, it has a plug on the bottom. I'll put fresh ethanol free gas and a little seafoam in it and see if that solves the problem without tearing into the carb. The plug was wet but looked OK. I blew it dry.

Poke out the jets

 

[Brokengun]

I am going to repeat what everyone else is saying. Take off the carburetor and clean it.

I had an engine that had the ran horrible. I cleaned the carburetor buy spraying carb cleaner through every hole and orifice on the carburetor, but it didnt really help; so I got a large mouth peanut butter jar and sprayed a whole can of Carb cleaner into the jar and let the carb set, covered in cleaner for a couple of days.

It worked.

Only other choice is to BUY a new carb

 

[jimg.allentown]

Put it back together. Fresh fuel with seafoam added. Let the fuel run through the carb. Closed the carb plug and it starts on the first pull with choke on, tries to run but still backfires through the carb and quits. I can keep it running with the choke on and feathered but it continues to backfire through the carb when I open the choke and then quits. I am letting it sit, hoping the seafoam cleans the carb. Is there anything I could spray into the carb that would clean it?

Carb cleaner needs to run through those little passages where the gas flows. Not where the air flows.

I can see that you are going to do everything possible to avoid doing what several people have advised - including myself. Why not just give in and clean the carb properly? Until you clean out whatever is plugging that jet, it simply will not run right.
The hole in question is very small, and the only sure way to make sure it is open is to put a fine wire through it.

 

[Richard G.]

I have a Champion 4000 watt generator. Hasn't been run in a year, was running fine but may have had ethanol gas in it. With the choke on it starts, but when you flip the choke off it backfires and quits. Won't rev up and run smoothly. I gave it a shot of ether with the same result. I am thinking a stuck valve or ethanol crap in the carb. I am going to drain the gas and replace with ethanol free and drain the carburetor. Then pull the sparkplug and flood with a 50/50 mix of ATF and acetone. Anything else I should try?

Just in case it is valve related, pour a little of Marvel Mystery oil in the gas and the oil.
It has worked for me several times.

 

[WNYBill]

Yes, you are right I am trying everything to avoid tearing into the carb. Afraid if I tear it apart the generator will never run again. However, it doesn't run now! Got to get it up on the bench so I'm not standing on my head to work on it. Standing on my head at 87 causes the ground to go out of focus.

 

[a49deere]

Yes, you are right I am trying everything to avoid tearing into the carb. Afraid if I tear it apart the generator will never run again. However, it doesn't run now! Got to get it up on the bench so I'm not standing on my head to work on it. Standing on my head at 87 causes the ground to go out of focus.

At 87, I'd let someone else look at it! In the long run it will be a lot less worry! (JMHO)

 

[TerryfromSWIowa]

If you are extremely lucky you can get it running and place your hand over the throat of the carb and suck the debris out. Might work 1 out of 10 times.

 

[Goose]

You "think" your grandson put ethanol in it? You're blaming ethanol without even knowing it it was involved?

 

[kevin110]

Regardless the type of fuel used; the carb needs to be disassembled and cleaned. kevin110

 

[Phill Tibbetts]

You "think" your grandson put ethanol in it? You're blaming ethanol without even knowing it it was involved?

Ethanol is well known for plugging the jet in small engine carbs if left setting. Why are so many people denying it causes problems. I won't put that crap in anything but my vehicles.

 

[wh]

Use nothing but ethanol based gas here. 2 generators, garden tiller, lawn mower and 2 old tractors. I do pour stabil in them at end of season. Run the generators at least every 2 months and always run them dry when shutting off. Never had a problem with gas. I do buy from a well known station. Did not use the garden tiller last year. Needed it a couple weeks ago. Looked in tank and showed 1/4 tank or so. Turned gas on, set choke, raised throttle and I will admit took a bit start. Had to pull the rope the second time before it was running. There are a few local stations I will not buy from.