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Author Topic: Onan 5000 gas generator  (Read 245 times)


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Onan 5000 gas generator
« on: August 26, 2017, 08:52:30 AM »
New 2014 Onan 5000 gas generator, beat there isn't 10 hours of run time on it, wouldn't start or stay running, even with a couple light shouts of either, determined old gas, drained old gas, cleaned tank, added 6 gallon
I can hear electric primer seemingly pumping, never could get gas to run out of carburetor bowl. My assumption is it's getting gas but, now no spark, ...because I shout a couple light shouts of either in carb... nothing! Hmm?


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Re: Onan 5000 gas generator
« Reply #1 on: August 26, 2017, 09:50:51 AM »
You said you added 6 gallons, but is your gas tank above the 1/4 mark? You know, once it gets to that level, the generator is no longer is able to siphon gas. You also said there was no gas in the bowl, but have you tried unhooking the fuel line to the carburetor and cranking the generator to make sure the fuel pump is working? Also, pull the spark plug wire and see if you have spark. If you have fuel and spark, you should be able to start it.  If it only has 14 hours, then it has sat for too long and the carburetor is likely gummed up.  Try running some Sea Foam thru it.

Gary RV_Wizard

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Re: Onan 5000 gas generator
« Reply #2 on: August 26, 2017, 10:51:17 AM »
10 hours in a 3 year old genset isn't near enough exercise, so odds are the carb is gummed up. It doesn't take much cause genset (and all small engine) carbs are finicky to begin with.  As cgmartin suggests, verify that fuel is being pumped to the carb and that the ignition sparks. If so, try the Seafoam or similar carb cleaner product, and pray that does the trick. Otherwise its probably carb rebuild/replace time..

"Old gas" is rarely a problem, more internet noise than common problem. I'm not saying no such thing, but nowhere near the frequency that the internet blather would have you believe. Old gas would be at the bottom of my list of poentential problems.
« Last Edit: August 26, 2017, 10:53:12 AM by Gary RV_Wizard »
Gary Brinck
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Home: Ocala National Forest, FL

Kevin Means

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Re: Onan 5000 gas generator
« Reply #3 on: August 26, 2017, 12:05:18 PM »
I'd be willing to bet that most genset problems are caused by lack of use. If your generator is actually three years old, and if you only ever ran it to exercise it (per Onan's recommendation) it would have about 72 hours on it. I think you're going to find that the carb is pretty gummed up.

We don't use our generator much, and in all honesty, I don't exercise as Onan recommends (monthly for two hours under a 50% load) but I do run it monthly under a heavy load (three AC units) for 45 minutes to an hour, and I've never had any problems. My BIL has an Onan 7 in his 20 year old motorhome, and it's got more than 2300 hours on it. The only problem he's ever had was the bendix gear in the starter. Onans like to be run.

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