Iwannago
Malta, NY
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My 2005 gas Onan 7.0 generator starts but only runs for a short 3 or 4 minutes before shutting off. It seems to keep choking itself and never gets to that smooth stage before it backfires and shuts down. it takes a few minutes though.
I have been lapse in starting it monthly and letting it run. It has little use but always worked before.
Any ideas what to look for.
Thanks
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irone10
las vegas nv
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Joined: 10/31/2009
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your carb could be gummed up from lack of use. may need a new carb
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xctraveler
Rochester, NY
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WHat is the level of fuel in your tank? Generator won't run if you have less than about 1/4 tank.
I had a similar problem on my old unit and it needed routine service, change oil, oil filter and air filter. They also regapped the plugs, no further problem. I now log my hour meter when I service the unit and make sure to change oil and filter every 150 hours or once a year and change air filter every 300 hours or when visibly dirty. I also am religious about running the generator under load every 30 days.
In your case I would start with oil and filter change and go from there. Then, once it is working set up a regular maintenance program. Dry camping every so often is very good for the generator too, they love be be run hard.
Paul
Trucking down the road in a 2004 Southwind 36E on Workhorse Chassis with a 2005 Toyota RAV4 AWD stick shift tow'd with US Gear Brake System. Check out my journal
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suchristo01
San Diego, CA
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Get a spray can of Berrymans B12 Chemtool remove the air filter and douse the carb. If you are at a place you can disconnect the fuel line, you could mix a carb cleaner with fuel and run it awhile. Hook it back up and run it under a small load until it gets smooth. If you are on the road, I use PRI G in the fuel tank, cleans the injectors, helps the gen, helps with bad fuel, I get mine at boat stores or CW if I am near one. Some guys use Seafoam. I have seen Onan techs spray the carb and charge all kinds of bucks...BTW my Onan is smooth as silk at every load. Gas Generators do much better running for long periods.
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Doug and Cassi Glass
Clifton Forge, VA
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Check the air filter. My 7.5 quiet diesel did exactly as you describe. Pulled out the air filter, knocked off the dirt and it started right up and stayed running. I didn't happen to have a spare.
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Daboo
Texas Panhandle USA
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Joined: 11/28/2001
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my gas genner did the same thing....changed out the fuel pump and all is well...I did a lot of searching before I arrived at this decision...talked to Onan got all kinda of answers, but one RVer on this forum told me about the fuel pump...he hit it right on the head..thats been about a year a go and it has been running great...cost==about 50$
Hello from the windy Texas Panhandle
Winnebago Adventurer 33V
Served proudly 1957-1965..U.S. Air Force
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EmergencyNrse
San Diego, Ca
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Good information from previous posts.
It runs so you have compression. What you describe is a fuel feed issue.
Begin with fuel filter to improve gas flow. Carb cleaner will take care of gummed up jets & valves in the carburetor.
Next would be the fuel pump which are known to fail on the Onan generators here & there.
Rarer would be fuel lines but don't discount that as a possible problem.
Good Luck.
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Dutch_12078
Great Sacandaga Lake, NY
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If it sounds like it's choking out, I'd suspect it might actually be "flooding out" due to a stuck float valve in the carb. The 7KW NHM in my Coachmen had that problem when I first got it, since it had been sitting unused for quite a few months at the time. I disassembled and cleaned it, and all is well now, but I understand the newer carbs are more difficult to service.
Dutch
'95 Coachmen Catalina 322XL
F-53 chassis, 460 V8
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Iwannago
Malta, NY
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I was pretty sure my problem was a gummed up carb so I took the air filter off several times and sprayed a lot of Gumout in there. Each time it seemed to be a little better. I also turned on the A/C to give it a load.
Finally after 15 minutes or so it wasn't getting any better so when I looked at the carb again I noticed a small adjustment on the side of it. I turned this a little and it ran smooth. Turned out to be the Altitude adjustment and it was set to one side. Evidently when I repeatedly removed the air cleaner I moved this adjustment when putting the snaps back on.
Seems to be Ok now. I will run it again in a day or so to make sure.
Thanks for your input.
Jim
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suchristo01
San Diego, CA
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Iwannago wrote:I was pretty sure my problem was a gummed up carb so I took the air filter off several times and sprayed a lot of Gumout in there. Each time it seemed to be a little better. I also turned on the A/C to give it a load.
Finally after 15 minutes or so it wasn't getting any better so when I looked at the carb again I noticed a small adjustment on the side of it. I turned this a little and it ran smooth. Turned out to be the Altitude adjustment and it was set to one side. Evidently when I repeatedly removed the air cleaner I moved this adjustment when putting the snaps back on.
Seems to be Ok now. I will run it again in a day or so to make sure.
Thanks for your input.
Jim My kind of trouble shooter. Always eliminate the cheap and easy first. If that does not work then go to more difficult and more costly. Good job...and run that generator hard...they really do work better with frequent use.
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