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Open Roads Forum  >  Class C Motorhomes  >  Class C

 > New Onan 4000 wont start

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rwgeiser

Anchorage, Alaska

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Posted: 02/20/19 08:14pm Link  |  Quote  |  Print  |  Notify Moderator

The Onans used to be 3 years, I would check again. I had a similar problem with my 2003 Fleetwood Storm when it was about 2 years old. Cummins fixed under warranty.


Ron & Del
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JaxDad

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Posted: 02/21/19 05:59am Link  |  Quote  |  Print  |  Notify Moderator

awesomeman wrote:

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


If it cranks and starts as normal per your original post, but shuts off as soon as you release the start button it is absolutely a ‘sefety’ of some form or an electrical gremlin.

BTW, the starter can be held down for an extended period of time after starting as per Cummins / Onan tech’s when I was diagnosing mine. Sometimes just running a moment longer can clear whatever issue is the problem.

D.E.Bishop

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Posted: 02/21/19 06:18am Link  |  Quote  |  Print  |  Notify Moderator

I am not sure but something clicks in my mind that even though there is usually a delay in power going to the 120 vac part of your coach, the genny starts producing immediately and that the outlet on the genny receives power immediately.

Doug may step in here soon and will know for sure.

The codes are not absolute, mine were all low oil pressure, but the problem was a faulty rotor/stator assembly.

You may be able to check the voltage at the generator by plugging in anything that gives a voltage reading immediately. My DMMs don't so I use a three light outlet checker.

It may be worth a try.


"I travel not to go anywhere, but to go. I travel for travel's sake. The great affair is to go". R. L. Stevenson

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DrewE

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Posted: 02/21/19 08:19am Link  |  Quote  |  Print  |  Notify Moderator

D.E.Bishop wrote:

I am not sure but something clicks in my mind that even though there is usually a delay in power going to the 120 vac part of your coach, the genny starts producing immediately and that the outlet on the genny receives power immediately.

Doug may step in here soon and will know for sure.

The codes are not absolute, mine were all low oil pressure, but the problem was a faulty rotor/stator assembly.

You may be able to check the voltage at the generator by plugging in anything that gives a voltage reading immediately. My DMMs don't so I use a three light outlet checker.

It may be worth a try.


I don't believe the 4KY has an outlet on the generator; at least, my (rather older) variant does not that I've ever found. To check the output you'd have to connect leads in the guts of the generator.

The delay in powering the motorhome comes from the time delay in an automatic transfer switch, which gives the generator time to come fully up to speed and for the voltage to stabilize and hopefully the choke turn itself off, etc.





bobndot

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Posted: 02/21/19 01:24pm Link  |  Quote  |  Print  |  Notify Moderator

Is there a governor on the Onan 4k ? Those symptoms might point to that.

valsamik

Virginia

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Posted: 02/22/19 03:06am Link  |  Quote  |  Print  |  Notify Moderator

I had similar issues. I think mine was related to fuel varnishing in the carb. Once I got the generator running it would search like it was a governor issue. I got some sea foam and mixed with fuel, disconnected the fuel line, inserted into the fuel line into the mixture, primed the generator, started it and let run for 15 minutes. Shut it down and let sit for about 30 minutes, reconnected the fuel line to the RV and started the generator again and ran for 15 minutes. I started putting fuel treatment in my gas regularly to prevent varnishing and make it a ritual to start the generator and let it run for about 15 minutes once every week to two weeks.


Mike,

2016 Winnebago Minnie Winnie

mgirardo

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Posted: 02/22/19 08:47am Link  |  Quote  |  Print  |  Notify Moderator

We had an issue with our brand new Onan in our 2009 Class C. Ours didn't even have 10 hours on it. My wife fired up the Generator while I was driving. She tried to heat something in the microwave for 1 minute, but the generator quit after 30 seconds or so. Restarted it and it quit again shortly after start up. Then it never fired up.

The error code, which I do not remember, basically translated to "have generator serviced". It turned out to be a fuel pump that the dealer replaced under warranty.

I would contact Cummins and find out what the warranty of the Generator is. It maybe more than 1 year as previously mentioned. They should also be able to help troubleshoot over the phone or email. Or at the very least find the nearest authorized repair facility.

-Michael


Michael Girardo
2017 Jayco Jayflight Bungalow 40BHQS Destination Trailer
2009 Jayco Greyhawk 31FS Class C Motorhome (previously owned)
2006 Rockwood Roo 233 Hybrid Travel Trailer (previously owned)
1995 Jayco Eagle 12KB pop-up (previously owned)

youracman

Denver, CO

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Posted: 02/22/19 02:10pm Link  |  Quote  |  Print  |  Notify Moderator

mgirardo wrote:

We had an issue with our brand new Onan in our 2009 Class C. Ours didn't even have 10 hours on it. My wife fired up the Generator while I was driving. She tried to heat something in the microwave for 1 minute, but the generator quit after 30 seconds or so. Restarted it and it quit again shortly after start up. Then it never fired up.

The error code, which I do not remember, basically translated to "have generator serviced". It turned out to be a fuel pump that the dealer replaced under warranty.

I would contact Cummins and find out what the warranty of the Generator is. It maybe more than 1 year as previously mentioned. They should also be able to help troubleshoot over the phone or email. Or at the very least find the nearest authorized repair facility.

-Michael


Good example of an "early failure part" the OP asked for, Michael. Wow! 10 hours!
He apparently removed the fuel line from the carb and verified fuel flow though, as he stated that his fuel pump was working.

'Twill be "velly intellesting" to find out what the cause of his failure was. Hope he reports back. These Onans can drive ya nuts at times.

Best......ed s


Ed Sievers, Denver, CO
07 WGO Outlook 31-C; '16 Kia Soul with 6spd DIY Tranny
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awesomeman

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Posted: 02/24/19 07:33am Link  |  Quote  |  Print  |  Notify Moderator

Read the fault code. Its a code 36. At least it doesn’t seem like a major code. Says to check fuel level, air filter, and spark plug and to check for mechanical damage

D.E.Bishop

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Posted: 02/24/19 08:40am Link  |  Quote  |  Print  |  Notify Moderator

Just one step in troubleshooting would be to check and verify that the generator is putting out 120vac. I have a 5.5K so I do have an outlet, if you don't, It is simple to remove the cover from the ATS and hook a meter to the cables from the generator and see if the generator is outputting and eliminating geting into the guts of the thing.

Doing that would eliminate one big possible problem.

If the generator is not generating 120 vac, the generator engine will not run, so check that the delay circuit is receiving power. As DrewE said there will not be any power to the system until the delay circuit closes and pulls in the ATS but the generator produces power as soon as the engine starts. Actually it starts producing power as soon as it starts turning. That is one of the first things the tech in the authorized shop did when mine failed.

What you have done is to make sure that the generator is outputting. Like I said, mine was not and threw a code 32, Low Oil.

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