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Open Roads Forum  >  Class C Motorhomes  >  Class C

 > New Onan 4000 wont start

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awesomeman

Florida

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Posted: 02/20/19 08:20am Link  |  Quote  |  Print  |  Notify Moderator

Hi. I’ve got a Winnebago 2018. Our generator has about 30 hours on it and was last used about 60 days ago. Everything worked fine. I went to crank up the generator today and it cranks, starts, and then immediately shuts off. After that it only cranks but will not start. It also didn’t sound like it stalled out. Sounded like it was shut off. Here’s what I e tried. It’s a Cummins Onan 4000
1. Oil was recently changed before last use and oil level is accurate
2. Primed the lines for 30 seconds as mentioned in manual
3. Tested fuel lines. Fuel pump is working and pumping fuel just fine.

What are the common early failure parts on these generators. It’s so weird since it is newer. Nothing should be failing at this point but these things happen. I know on my last generator the oil pressure sensors were notorious.
Any help is appreciated as I’ve literaly owned the rv just over a year and the warranty is out. Lol.
Thanks

wildtoad

Blythewood, SC

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Posted: 02/20/19 08:31am Link  |  Quote  |  Print  |  Notify Moderator

How much fuel is in your gas tank? Most will not start if there is less than 1/4 of ta tank. Check the warranty on the Onan itself, it may be longer than your MH’s warranty.


Tom Wilds
Blythewood, SC
2016 Newmar Baystar Sport 3004

awesomeman

Florida

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Posted: 02/20/19 08:44am Link  |  Quote  |  Print  |  Notify Moderator

Sorry forgot to mention. Full tank of gas

Hank85713

Tucson, Az

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Posted: 02/20/19 09:18am Link  |  Quote  |  Print  |  Notify Moderator

I had a gen that would not start and it was due to the low oil level sensor not working. Called and they told me to disconnect, then start. I did and it works fine now with the sensor wire being connected. It just could be something like that. Did you pull spark plug and check?

my hen is slow to start so sometimes need to exceed the 20 second prime run

T18skyguy

Eugene, OR

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Posted: 02/20/19 09:20am Link  |  Quote  |  Print  |  Notify Moderator

Yes I remember those troublesome oil sensors. You can buy a troubleshooting manual for your unit from Cummins.


Retired Anesthetist. LTP. Pilot with mechanic/inspection ratings. 2017 Jayco Greyhawk 31FS. Wife and daughter. Three cats which we must obey.

bobndot

USA

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Posted: 02/20/19 10:34am Link  |  Quote  |  Print  |  Notify Moderator

ASAIK, there is a light that blinks codes. EX : 3 blinks then 4 blinks is a code 34. You need to look up the code.
If it stumbles/coughs when it stops it would lead me to think it was carb related. If it stops like you are pushing the STOP button, then I would think its an electrical component not functioning.

It might not be detecting 120v after it starts, that will cause it to shut down like a dead stop, as if you pushed the stop button.

Chum lee

Albuquerque, NM

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Posted: 02/20/19 03:27pm Link  |  Quote  |  Print  |  Notify Moderator

First, read the trouble shooting section in your owners manual. If no help, then take it to an Onan dealer and tell them to fix it. At 30 hours on the clock, it's still gotta be under warranty. The more you mess with it, the greater the chance they (Onan) will blame you for whatever issue(s) you are having.

Chum lee

JaxDad

Greater Toronto Area

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Posted: 02/20/19 03:33pm Link  |  Quote  |  Print  |  Notify Moderator

Is your house battery fully charged? There’s a voltage sensor that shuts the unit down on low voltage, it’s overridden by the starter button so the dip in voltage caused by the starter doesn’t foul things up.

awesomeman

Florida

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Posted: 02/20/19 06:15pm Link  |  Quote  |  Print  |  Notify Moderator

House batteries are on full charge. Warranty one year and no dealers are close by. Cheaper and easier to make some educated guess. I’ve worked on my share of generators and am certain it’s soenthing stupid. Just trying to narrow my plan. Went through the guide. Nothing has low voltage

youracman

Denver, CO

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Posted: 02/20/19 07:28pm Link  |  Quote  |  Print  |  Notify Moderator

I agree, it sure as heck seems like some kind of "infant mortality" electrical/electronic issue, awesomeman: but these things sometimes defy logic IMHO.

As you know it is recommended to start the Onan once a month and run it under 1/2 load or more for 30 min to an hour (the load application is to drive moisture out of the generator windings etc, primarily). Hard to believe that 60 days would cause varnishing in the carb, but just for grins: What do you think about removing the air filter; spraying in a bit of starter fluid, and than see if it will at least "pop"? Also, even though your coach batteries are up to snuff, you might start the big engine and let it put a little more "umph" into the coach batteries (automatically via the boost solenoid ..... just as when driving.) I know mine sounds like the Onan starter spins just a teensy bit faster when the Ford is running.

I guess if the above doesn't get at least a "pop", you might pull the spark plug and see if the points are clear ...... and maybe just replace it (cheap).

Good luck and keep us posted, please. We are all "still learnin' ".

Safe travels........... ed s


Ed Sievers, Denver, CO
07 WGO Outlook 31-C; '16 Kia Soul with 6spd DIY Tranny
"Be the person you needed when you were younger"


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