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New Onan generator died

daugen
Explorer
Explorer
Our 2013 Itasca Sunstar 27N comes with the 2500kw Onan gen running on gasoline. It was always hard starting, taking up to ten seconds of cranking. We were then told to hold down the stop button to prime it first. Ok..., No difference whatsoever in starting.

Then yesterday, after running for about an hour, the gen stopped.
Smell of gasoline from outside the compartment. It was late, so I waited until this morning to investigate and let it cool down.

Ok, what should I look for? 24 hours on gen. Will check all breakers first, then will see if there's a fuel filter in there. Then will try to restart. The oil is fine...

It's the smell of gasoline outside the motorhome that concerned me.
That I need to find the source or cause of for sure.

I'm not a mechanic, and the new rv is headed back to the dealer anyway, but I'd sure like to figure this out today, if that's possible.

After I check on it, I'll let you know what I find, which I expect to be nothing visible. There is a manual start on the gen right on it and that's where I'll see if she fires up.
13 REPLIES 13

rgatijnet1
Explorer III
Explorer III
As mentioned a few times, the electric fuel pump is the problem. They have had a recall on them. As the temperature increases, the fuel pump will fail. When things cool off, it is not unusual for the generator to start up, but then when temps go up again, it will quit.

daugen
Explorer
Explorer
John, good to hear. Wish they would have built it right too...
not "their" fuel pump I'm sure.

John_S_
Explorer II
Explorer II
i will say i f it still give s you trouble go to Cummins they will fix it right the first time.
John
2015 Born Free Royal Splendor on a Ford 550
2018 Rubicon
Boo Boo a Mi Kie
42' 36' & 34 Foretravels sold
2007 Born free 24 sold
2001 Wrangler sold
2012 Jeep Grand Cherokee Overland sold
Susie Dolly, Lolly &Doodle (CKC) now in our hearts and thoughts

daugen
Explorer
Explorer
The mystery remains a mystery. Coach is level and full of gas. There is no fuel filter anywhere I can find. There are no leaks anywhere I can find, nor loose fittings. No breakers of any kind tripped.

The next morning it started right up again, though it acted very strange, and would not start from the control on the unit. But when I hit the start button up in the rv, it started normally, albeit it still takes five to eight seconds of cranking to start.

the only way to really test the gen is to run it for another hour under load, but it bothers me it would just cut out for no apparent reason. Which leads me to believe that the fuel pump is very, very suspect. BTW it is a 4kw Onan, not a 2.5 as previously written.

We are off tomorrow to our first rv campground with full hookups, so we won't need the gen, but I'll test it anyway. And then the following week the rv goes back to the dealer to get suspension upgrades put on, so it looks like the gen can wait until then to get looked at, and for sure check for a recall.

thanks for all the suggestions, I really appreciate it.

Stormdog
Explorer
Explorer
The Onan on our new unit had the exact same symptoms as you describe until it just wouldn't start at all. Turned out to be the fuel pump. Newmar said Onan has had some problems with fuel pumps lately. It works fine after being replaced.

DSDP_Don
Explorer
Explorer
daugen.....As "Don Don" stated, do you have more than a third of a tank of fuel in your motor home? The gen will stop and starve for fuel at that point.

I haven't looked at a gas Onan in years and I'm guessing the new ones don't have it anymore, but just in case, my older 4K gas Onan had an altimeter lever and a winter/summer lever. The altimeter lever was suppose to be set to your estimated altitude and the other lever set to the correct season.
Don & Mary
2019 Newmar Dutch Star 4018 - All Electric
2019 Ford Raptor Crew Cab

Don_Don
Explorer
Explorer
Do you have enough fuel in your tank? How much do you have?

mustang652
Explorer
Explorer
The Onan on my new unit failed with about 35 hours on it a couple of weeks ago. Was having the oil changed on it after the first trip at CW here in Vegas and after completion of oil change, it would not start. Mechanic said that Onan had a recall out on the fuel pump.
Stan, Shirley & 2 Schnauzers
RV: 2014 Itasca Sunstar 35F
USAF Retired, Life Member: VSPA, VVA, DVA,VFW

daugen
Explorer
Explorer
Alid, great advice, I'll follow it, many thanks. Drew
Dversta, good idea on the no spark, I agree, but due to engine
malfunction or due to a breaker or some nanny device turning it off just as designed?
Nothing like a good mystery.

daugen
Explorer
Explorer
JumboJet, thank you. I understand flooding while starting..., but after an hour of constant running? Luckily the motorhome is parked outside our house for the moment, so after breakfast I'm going to investigate. I'm a past active fireman and the smell of gasoline gives me the willies. Explosive vapors, points of ignition, all that good stuff. This is a single cylinder motor running at 3600rpm. What would make it falter and die, and then smell strongly?

I grew up on a farm and love machinery, so I've had my share of starting issues.
Engines stopping usually means something is seriously unhappy.
And if it died from a breaker clicking, and the engine kept feeding fuel as it wound down, well that would sure create a smelly exhaust.
Engines in closed compartments directly under our bed are a concern to a risk averse guy. Jumbo, I'm looking for loose connections/drips after i start it up, with the door open for lots of air in there. Really don't want a new haircut this morning.

dverstra
Explorer
Explorer
First of all, I am not a mechanic. That said, the smell of gas could just mean that you are getting too much fuel into the motor(it's flooded). Or the right amount and don't have a good spark. When it stopped, did it run real rough before or did it just quit?
Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "...Holy Cow....what a ride!"

2007 Holiday Rambler Navigator
2013 Honda CRV
Returned Peace Corps Volunteer - Sierra Leone

alid
Explorer
Explorer
daugen wrote:
Our 2013 Itasca Sunstar 27N comes with the 2500kw Onan gen running on gasoline. It was always hard starting, taking up to ten seconds of cranking. We were then told to hold down the stop button to prime it first. Ok..., No difference whatsoever in starting.

Then yesterday, after running for about an hour, the gen stopped.
Smell of gasoline from outside the compartment. It was late, so I waited until this morning to investigate and let it cool down.

Ok, what should I look for? 24 hours on gen. Will check all breakers first, then will see if there's a fuel filter in there. Then will try to restart. The oil is fine...

It's the smell of gasoline outside the motorhome that concerned me.
That I need to find the source or cause of for sure.

I'm not a mechanic, and the new rv is headed back to the dealer anyway, but I'd sure like to figure this out today, if that's possible.

After I check on it, I'll let you know what I find, which I expect to be nothing visible. There is a manual start on the gen right on it and that's where I'll see if she fires up.


It is obvious that you have some type of fuel leak. I recently had a similar problem with my 2009 onan.
Here is how I found my fuel leak.
1. Open up the cover so you can see the generator..
2. locate the carburetor and the fuel line that runs to it.
3. if yours is like mine you have a start button located right at the generator itself.
4. hit the prime function and see if you can find the leak..
5. especially look at the fitting going to the carburetor.
(on my genny.. this fitting was a fuel filter.. Onan has replaced it with a fitting doing away with this filter.. and only has one at the fuel pump.. It is a known problem with these fuel filters leaking at the carb. that's why Onan no longer sells it.)
6. if it isn't leaking at the carb.. just follow the fuel line down to the fuel pump checking for leaks.
2009 Winnebago Adventure 32h
2006 Terry Quantum 330FKDS (beach getaway)
2003 Aprilia Atlantic 500
2007 Honda Reflex
2 house rabbits "George and MiMi"

JumboJet
Explorer
Explorer
A flooded condition could result in gasoline smell, resulting from automatic choke sticking. A loose fuel line connection could cause the same.