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Old 01-11-2019, 09:34 AM   #1
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Cummins Onan Generator won't start?

Won't start, tried removing the carburetor and cleaning the carburetor, major pain in the butt but went sort of ok, still couldn't get it to start, read somewhere that you couldn't rebuild these carburetors but instead had to replace them at a cost of about $350. Is that right and what do most folks here do about the generator issue? Also how much gas needs to be in the fuel tank in order for the Generator to get it's supply? 1/4 tank of gas ok?

These Briggs and Stratton generators run forever, years and years but the Onan if you don't start it up every month or so, carburetor plugs up. Don't understand that.

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Old 01-11-2019, 09:45 AM   #2
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I'm no expert. But here's what I'd do. That doesn't mean I'm recommending to you. Could be dangerous.

But I lover ether. A little starter fluid has revived some of my landscape equipment many times. Your 1/4 tank may also be the issue. I can't remember if its the generator or the external pump that stops around 1/4 tank.

My Onan runs well but as you said, I start it every month or so and the fuel always has stabilizer.

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Old 01-11-2019, 10:48 AM   #3
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You need a minimum 1/4 tank. Maybe more/less. Put 5 gallons in the tank and try again.
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Old 01-11-2019, 03:48 PM   #4
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We just had a problem getting ours to start, too. After changing the spark plug, using ether, etc., it still wouldn’t start. It turned out to be the generator’s oil level. Although it was on the stick, it was on the low side.

We added some, and it still wouldn’t start initially. Tried again later that afternoon and it started right up. Apparently the sensors needed to think a little bit about the oil level, even though the stick said full.
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Old 01-12-2019, 01:23 PM   #5
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I have begun using Recreation gas (100% gasoline (no ethanol) designed for marine use) in "all" my small engines including generators. I still use stable but not as important when the ethanol has been eliminated. Since making this change my starting problems have been eliminated. Should mention I also start and run all my generators for 30 minutes at least once every 2 to 3 months.
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Old 01-12-2019, 01:25 PM   #6
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Junior Member Join Date: Jan 2014 Posts: 11 Cummins Onan Generator won't start?

Had a similar problem when my RV was new. The problem: low oil. Put more oil in and the generator started just fine.
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Old 01-12-2019, 01:40 PM   #7
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If the issue is low fuel -- and at 1/4 tank it could well be, especially if you're not level and the generator's feed line is on the "shallow" end -- then after you add fuel you'll need to prime the generator. To do it, instead of pressing the "start" button, press the other side of the toggle switch and hold it for about 30 seconds, then try starting.

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Old 01-12-2019, 01:40 PM   #8
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I helped a friend with this problem. Problem turned out to be. gum in carb float valve from inactivity Took it apart and cleaned it with choke cleaner. Problem solved. You could also take carb to a small engine shop to clean it.
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Old 01-12-2019, 01:59 PM   #9
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Gasoline deteriorates over a fairly short period of time so Stabile is mandatory for any tank that is not used and replenished within a few months. Ethanol makes things worse. Just going to fuel without ethanol will not stop the deterioration. When I had my shop we had a car come in that had fuel in the tank but would not run. Fresh fuel fixed it. Fuel that does not have Stabile in it will evaporate in the carb and form an almost impenetrable varnish. I have had to physically scrape it off. BG44K will dissolve it, but it takes time.

Always use Stabile in your fresh fuel that is going to sit around for a while.
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Old 01-12-2019, 02:00 PM   #10
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I use an ultrasonic tank for cleaning carbs these days they have too many plastic parts that are not removable. The old chemical dip I used for 35+ years destroys the plastic. The problem with having your oil low on the stick is when engine is cold and you start cranking it throws the oil around inside and it doesn’t drain back fast enough to cover the sensor. So it thinks it is even lower. No reason to check it and not add while you are there if needed.

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