No. Find the real reason it running rough.

The last thing you want is the A/C taking a crap, when the wife is having her monthly visitor....

 

not stored with any gas. Or very little

Pull and clean the sparky?

 

If it's a ONAN, the pilot circuit in that carb clogs very easily. Seafoam isnt going to get it done.

 

My Onan RV QG 5500 would not start after it setup over the winter. A new carburetor solved the problem. It only had about 10 hours of use on the generator, as it was new. I read posts on this forum about Seafoam and it's ability to prevent the carb fouling. I did a modification to my fuel feed. Between the discharge of the fuel pump/filter, I cut the tubing and installed a 3-ported valve. One position of the valve allows flow of fuel from the tank to the generator engine. The other position of the valve has a rubber tube that will supply a Seafoam and gas mixture (mostly seafoam) to feed the generator while cutting fuel from the RV tank.

Before I setup the RV for the winter I fill a 1-cup bottle with 1 parts fuel and one part Seafoam or 100% seafoam. I flip the valve to cut off fuel from the RV tank and allow the generator to suck in the fuel mixture from the bottle until the generator shutsdown. I did this before last winter so I'll find out if this works. I intend to do this procedure about every other month from now own. I prefer using 100% seafoam, about 1/2 cup is all you need to clean the entire fuel circuit. I plan to get a narrower bottle and reduce the amount of Seafoam needed because the generator runs a long time on 1 cup of mixture, too long. Trust me, its worth it because Onan makes no replaceable parts for the carburetor and it took me a couple hours to replace it and its a pain to get to it.

Has anyone on this site used 100% seafood in this manner, did the engine continue to run properly? I plan to test this out soon.

 

im not saying thats going to hurt anything, but im not typically on the "additives fix problems" side of the fence. Id check the plug, the filters, and maybe either drain the gas, or top off with fresh and see how it goes. Theres only so much a liquid in a can can do.

 

Is the pilot circuit easy to get to? Already changed oil and air filter. That’s about as mechanical that I am on these things. I keep it clean and always use fresh fuel but it just seems to be a little rough right now

 

If Onan, does it keep running roughly, or does it almost want to die or actually dies? My Onan 4K would run for about 15 mins, very rough, then die. Then would start again, run rough for a bit, then die. Sounding like it was starved for fuel; replacing the fuel pump and filter solved it. $50.

Unfortunately, the fuel pump and filter is usually buried inside the generator casing back behind the circuit board. So if you end up going that route, I would relocate the fuel pump outside the generator (but inside the trailer doghouse) where it's easy to get to and replace in the future if necessary. Easy mod.

 

Yes it is an Onan 4000. It does not die or even sound like it is going to. Just not smooth. Sort of like listening to the RPM fluctuate up and down. Ran it for about a hour last weekend and it never stopped. It just does not “purr” like it used to

 

Most have a "altitude adjusting " knob.

 

Fouled plug maybe. IMO I would never run it totally out of fuel, asking for more problems than dead fuel.

 

I suggest to install a fuel shutoff valve on your generator, turn it off and let it run out of fuel.
Another, use LUCAS fuel treatment in the tank, it acts as a fuel stabilizer, 6 months even to one year setting, I’ve never had a issue.
I also never start it up every month like they suggest because there’s no fuel in the carb to screw things up.
Been doing this on 2 RV generators for more that 20 years with no problems.
I also will only run premium fuel, it’s well worth have a better running engine with fuel that’ll last a little longer setting.

 

Been running seafoam in our Onan 4000 for 6 years. Only time I didn't was when it sat for 3 months after I filled it up on the way home from a trip. It ran rough and surged when I did start it. Ran seafoam through it , a can for the 18 gal tank, and within a half hour of running it lined out smoothly and is still runs fine. I am usually very careful to run it for a hour a month under load per the manual. I would definitely try seafoam before taking things apart, your only out about $6 and a hour of you time.

 

We only run the REC fuel with no ethanol in it if it's available well worth the extra money as it doesn't gum up the carb. while not in use nearly as bad as any gasoline bought with ethanol in it.

 

I wish I could find REC fuel. I have never seen it in Norther CA.

 

New here, actually my first post. Hello to all.
I use seafoam for when I store my snowmobiles, they are the worst for storing since they sit through the hot summer, unlike atv's, generators, chainsaws, weedeaters, etc.
My experience with all of my equipment is if the fuel has ethanol in it, seafoam or stabil don't help at all for storage...every time I stored with fuel that had ethanol in it I had to pull the carbs and clean them. It was always the pilot jets that were plugged. What I do now is put non ethanol premium in everything before it gets stored, add proper amount of seafoam, and that hasn't failed me yet. I make sure to add the non ethanol fuel and seafoam on the last camping trip, last couple yard mowings, last couple of snowmobile rides, etc. so that all of the ethanol fuel has been used and it has nothing but the non ethanol left in it. If it has a fuel shut off then I will shut it off and run the carbs empty. I have read that marine type stabil, the blue stuff, works with ethanol but I have no experience with trying that. Ethanol is nasty stuff when it sits for very long. In my sled carbs they would have a yellowish color of varnish on them and a ton of particles of crud floating around in the bowls. Non ethanol has a green colored type varnish with much less crud particles in my experience.
I did have my lawnmower run rough last year when I took it out of storage and I realized I had forgot to put seafoam in it before putting it away. Hoping to not have to go through the fuel system on it I gave it a stiff dose of seafoam, and amazingly it cleared up the rough running by the second time I used it. That normally doesn't happen for me, but if the blockage it slight there is a chance.

Starting it and running it every 3 weeks or so through the storage period can also work, but make sure to run it long enough that it gets up to operating temperature.

I would say it is worth trying a dose of seafoam or some STP injector/carb cleaner in your generator to see if it helps first. If it doesn't, it is more than likely a dirty jet that has a bunch of crud trapped in it and it'll need to be manually cleaned out.

 

Update on my issue. Added a 16oz can of Seafoam to about 12 gallons of gas. Started the gen and it ran rough for about 15 mins then quieted down and is running smooth again. Not saying the seafoam is a cure for everything but it is working for me.

If I have to break it down and manually clean the carb what shouldn’t I use to clean it? I figure I can probably find some how to video on YouTube or someplace to show my how.

 

I haven't ever had to do a generator, but have done sled carbs more times than I remember and a few buddies atv's that didn't store them properly. I would say if it is running good now it probably passed the blockage and you'll be fine. I had the same thing happen with my lawnmower, seafoam is pretty good stuff IMO.
If you do ever need to clean carbs, just use whatever brand of carb cleaner. Make sure to remove the jets when you clean, just spraying out the bowl and passages or soaking in a parts cleaner doesn't get the tiny pilots clean. I will remove them, spray carb cleaner through them, then spray some air through them, and then hold up to a light to verify they are clear. Pilots have a tiny hole and can be tricky to see through, but if you hold them right up to a light and move them around a bit you'll eventually find the position so you can see through them. If the hole isn't...and I can't stress this enough...perfectly round, then there is still blockage. Many, many times I've had to run a small wire through them to get the blockage out. It's just too small of a hole to be able to get much carb cleaner pressure or air pressure through to remove the crud. A wire cut off of a wire brush or a welding torch tip cleaner works well, but be careful not to ream the pilot out to a larger size by choosing too big of a size torch tip cleaner, it should just go through smoothly. Torch tip cleaners are abrasive on the end and will cut the hole bigger if you don't match the size well.
I'm betting you're good to go though. Make sure to try to store next year with non-ethanol fuel treated with seafoam (if your area has the premium non-ethanol available). If it doesn't I'd try the marine stabil, but be warned that it's quite a bit more expensive than normal red stabil, about $30 a bottle the last time I looked.

 

Some good advise. Thanks for posting, it pretty much mirrors my experiences with stuck carbs.

 

I had a Honda 2000i that started running rough, Honda guy quoted me a $$ to rebuild the carb, put a few ounces of Sea Foam in the tank and it cleared up the rough idle and surging in like 30-45 seconds.

 

The ultrasonic cleaners do a good job also of carb cleaning with water and dish soap.

I got a dual fuel propane/gas generator that I run on propane to avoid just that problem though. Propane doesn’t go bad in storage, burns cleaner, and won’t gum up the carb.

 

Dump the fuel, there have been many people using stabil and it causes problems around here for mowers etc. I'd dump the fuel, get some Seafoam cleaner, and Seafoam fuel treatment. Put fresh fuel in with the correct amount of seafoam, and then spray the seafoam cleaner into the air intake while its running. It will clean it all up, it will smoke a bit while doing this which is normal.

 

It's harder to find here where it's more populated but some have had success at marinas. We get it from a petro bulk plant.

 

I use only non ethanol fuel in the fuel cell of our Toy Hauler as well as in all of our small engines and motorcycles. I also add Seafoam in every tank. It is great preventative maintenance and also contains stabilizer. I also run the generator out of fuel prior to covering the the TH ever winter. Same with the small yard care equipment. Seems to work.....

 

Carburetor, carburetor, carburetor..............consistent in most of the posts also. My wife has a mobile grooming truck with a Generac QP7500 watt generator. The first went 6800 hours before self-destruction and the second is currently at 6300 hours. Every single time that either developed a miss it ALWAYS was the carburetor. They are extremely easy to take apart and clean, just don't lose any parts. Have purchased 5 new carburetors in their lifetime, but most of the time they just need cleaning. My two portable generators have suffered the same issues with the same results; carburetor cleaning, although they were dirty and gummy from little use versus the bigger generators from just being dirty from daily use. I quit messing with additives and just took off, disassembled, and cleaned them, and every time the problem was resolved. To date, I have never replaced a fuel pump, but they always get fuel filters regularly replaced. The ideal situation is to run them every week, but not many of us do that. Carburetors and fuel are generators weak spot and 100 hour interval oil changes are critical.

 

Seafoam in a 100% strength in my experience will make the engine smoke a lot, and no it will not run... if it does run itll be poorly. However when your winterizing, running 100% seafoam through the system until it dies is probably the best thing you can do.

 

I am not a guy that believes additives will fix everything but dang one tank of fresh gas and seafoam has really cleaned up and made my generator run smooth