| Onan Idle Surge [message #305714] |
Sun, 21 August 2016 13:39  |
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J Green
Messages: 36
Registered: July 2016
Location: Arizona
Karma: 1
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Member |
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Greetings,
While running my Onan 6k while parked I noticed the generator tends to surge. I've linked a video to give a better idea of what I'm describing. This occurs with or without a load. I've had everything inside the coach that would draw power turned off - no AC, no refrigerator, no lights, and nothing plugged in to outlets and the "surge" continues to occur. When I turn the AC on the fan from the AC will match to surge of the generator.
This did seem normal to me so I thought I would ask the group. I recently replaced the starter on the Onan and was curious if I'm on to the next "opportunity" with Onan the Barbarian. Or, is this possibly a symptom of something being wired incorrectly.
https://drive.google.com/open?id=0B8PRwI7S3xRhY2R5aW9Jb0p4TkU
Thanks in advance for any thoughts and opinions ... even if this is normal I'd like to know.
Regards,
John
J Green
Phoenix, AZ
'77 Kingsley - aka Edna "Big Bertha" Green
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| Re: [GMCnet] Onan Idle Surge [message #305716 is a reply to message #305714] |
Sun, 21 August 2016 13:45  |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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Senior Member |
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Sounds like a fuel or carb problem.
Make sure you have a clean air filter. Then check the o ring around the main jet. They sometimes leak air which will give a surging. If the o ring is worn you can replace it with a round 1/8” id x 1/4” od ring.
If that doesn’t fix the surging you might need to clean the carb and adjust the low speed idle and high speed.
Emery Stora
77 Kingsley
Frederick, CO
> On Aug 21, 2016, at 12:39 PM, J Green wrote:
>
> Greetings,
>
> While running my Onan 6k while parked I noticed the generator tends to surge. I've linked a video to give a better idea of what I'm describing. This
> occurs with or without a load. I've had everything inside the coach that would draw power turned off - no AC, no refrigerator, no lights, and nothing
> plugged in to outlets and the "surge" continues to occur. When I turn the AC on the fan from the AC will match to surge of the generator.
>
> This did seem normal to me so I thought I would ask the group. I recently replaced the starter on the Onan and was curious if I'm on to the next
> "opportunity" with Onan the Barbarian. Or, is this possibly a symptom of something being wired incorrectly.
>
> https://drive.google.com/open?id=0B8PRwI7S3xRhY2R5aW9Jb0p4TkU
>
>
> Thanks in advance for any thoughts and opinions ... even if this is normal I'd like to know.
>
> Regards,
> John
> --
> J Green
> Phoenix, AZ
> '77 Kingsley - aka Edna "Big Bertha" Green
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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| Re: [GMCnet] Onan Idle Surge [message #305718 is a reply to message #305714] |
Sun, 21 August 2016 13:49 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Onan's don't idle. They are supposed to run at a steady speed that produces
50 to 60 hz and 120 to 130 volts A.C. That should be around 1725 rpm + or-
a bit. If yours is surging, the carb high speed mixture is out of
adjustment. If you have a manual for your model, read it and follow the
instructions. If no manual, let us know.
Jim Hupy
On Aug 21, 2016 11:40 AM, "J Green" wrote:
> Greetings,
>
> While running my Onan 6k while parked I noticed the generator tends to
> surge. I've linked a video to give a better idea of what I'm describing.
> This
> occurs with or without a load. I've had everything inside the coach that
> would draw power turned off - no AC, no refrigerator, no lights, and nothing
> plugged in to outlets and the "surge" continues to occur. When I turn the
> AC on the fan from the AC will match to surge of the generator.
>
> This did seem normal to me so I thought I would ask the group. I recently
> replaced the starter on the Onan and was curious if I'm on to the next
> "opportunity" with Onan the Barbarian. Or, is this possibly a symptom of
> something being wired incorrectly.
>
> https://drive.google.com/open?id=0B8PRwI7S3xRhY2R5aW9Jb0p4TkU
>
>
> Thanks in advance for any thoughts and opinions ... even if this is normal
> I'd like to know.
>
> Regards,
> John
> --
> J Green
> Phoenix, AZ
> '77 Kingsley - aka Edna "Big Bertha" Green
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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| Re: [GMCnet] Onan Idle Surge [message #305719 is a reply to message #305714] |
Sun, 21 August 2016 14:01 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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You might want to adjust the idle screw by backing it up slowly with no
load.
With load, there is a screw that is located at bottom of the fuel bowel.
On Sun, Aug 21, 2016 at 11:39 AM, J Green wrote:
> Greetings,
>
> While running my Onan 6k while parked I noticed the generator tends to
> surge. I've linked a video to give a better idea of what I'm describing.
> This
> occurs with or without a load. I've had everything inside the coach that
> would draw power turned off - no AC, no refrigerator, no lights, and nothing
> plugged in to outlets and the "surge" continues to occur. When I turn the
> AC on the fan from the AC will match to surge of the generator.
>
> This did seem normal to me so I thought I would ask the group. I recently
> replaced the starter on the Onan and was curious if I'm on to the next
> "opportunity" with Onan the Barbarian. Or, is this possibly a symptom of
> something being wired incorrectly.
>
> https://drive.google.com/open?id=0B8PRwI7S3xRhY2R5aW9Jb0p4TkU
>
>
> Thanks in advance for any thoughts and opinions ... even if this is normal
> I'd like to know.
>
> Regards,
> John
> --
> J Green
> Phoenix, AZ
> '77 Kingsley - aka Edna "Big Bertha" Green
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Onan Idle Surge [message #305720 is a reply to message #305714] |
Sun, 21 August 2016 14:13 |
Jim Miller
Messages: 501
Registered: March 2008
Karma: 10
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Senior Member |
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On Aug 21, 2016, at 2:39 PM, J Green wrote:
> While running my Onan 6k while parked I noticed the generator tends to surge. I've linked a video to give a better idea of what I'm describing. This
> occurs with or without a load.
In addition to what others have suggested you might want to check the spring on the governor arm. If someone in the past has moved it too far aft toward the generator section then the control function becomes more sensitive and the unit may not stabilize. Usually the first or second hole (as viewed from the blower end of the engine) is good enough to be responsive to applied load but not so sensitive as to produce oscillation. There is a section in the service manual that addresses the governor sensitivity.
You did not mention whether this was a problem that developed on a machine that was previously working correctly - or if you are a new GMC owner that is just getting the Onan running. The troubleshooting process might be different depending on the history of the machine and any work you’ve already done.
—Jim
Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: [GMCnet] Onan Idle Surge [message #305788 is a reply to message #305720] |
Mon, 22 August 2016 00:34 |
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J Green
Messages: 36
Registered: July 2016
Location: Arizona
Karma: 1
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Member |
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Thanks everyone. I've made note of the suggestions and will attempt from
simplest to most complex on my next trip up north where my Kingsley is kept
during the summer months.
I am a newly minted GMC owner and recently replaced the starter on the Onan
6k. We've not had occasion to use the generator while camping so I'm still
putting it through it paces before relying on it while camping.
My wife and I were doing work in the coach and since we hadn't been up for
a few weeks I started everything up, including fridge and AC (both of them)
while we sat idling. That's when I noticed the surge (apologies for calling
that "idle"). I proceeded to turn off things one at a time to see if it was
a load issue and the surge persisted even with everything off. It would
cease for a minute or two but resume.
I plan on checking and replacing the air filter first, then proceeding on
with the items suggested one by one until the surge is resolved. I won't be
able to get up to the RV for another week, but once I've attempted the
fixes I'll report the outcome.
Thanks again for everyone's suggestions.
Regards,
John
On Sun, Aug 21, 2016 at 12:14 PM Jim Miller wrote:
> On Aug 21, 2016, at 2:39 PM, J Green wrote:
>
>> While running my Onan 6k while parked I noticed the generator tends to
> surge. I've linked a video to give a better idea of what I'm describing.
> This
>> occurs with or without a load.
>
> In addition to what others have suggested you might want to check the
> spring on the governor arm. If someone in the past has moved it too far aft
> toward the generator section then the control function becomes more
> sensitive and the unit may not stabilize. Usually the first or second hole
> (as viewed from the blower end of the engine) is good enough to be
> responsive to applied load but not so sensitive as to produce oscillation.
> There is a section in the service manual that addresses the governor
> sensitivity.
>
> You did not mention whether this was a problem that developed on a machine
> that was previously working correctly - or if you are a new GMC owner that
> is just getting the Onan running. The troubleshooting process might be
> different depending on the history of the machine and any work you’ve
> already done.
>
> —Jim
>
>
> Jim Miller
> 1977 Eleganza
> 1977 Royale
> Hamilton, OH
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
J Green
Phoenix, AZ
'77 Kingsley - aka Edna "Big Bertha" Green
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| Re: [GMCnet] Onan Idle Surge [message #305790 is a reply to message #305788] |
Mon, 22 August 2016 00:52 |
Bullitthead
Messages: 1411
Registered: November 2013
Karma: 5
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Senior Member |
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Make sure the throttle shaft is tight in the bellcrank. You can use an automatic centerpunch to swell the shaft enough to make the connection tight. That was causing the surging on an Onan Emerald that I was resurrecting from Craigslist.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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