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Onan Dies After about 15 min [message #284046]

Wed, 05 August 2015 15:11

jtfred

Messages: 132
Registered: January 2015
Location: Grand Marais, MN

Karma: 0

Senior Member

It seems that I'm not done troubleshooting my Onan. It will start when cold and sun smooth. after about 15 minutes of running it will stumble and die. I can get it to start again sometimes, but it will only run about 5 minutes before it dies again and won't start again. Once it has cooled it will usually start and run for another 10 to 15 minutes.

I have checked the fuel and the new pump seems to be providing plenty of fuel. I'm thinking it must be a problem with the ignition. I have tested the coil according to the manual (cold) and it looks good. I haven't tested it yet just after failure. I will do that next.

Any recommendations on anything else I should look at?

Thanks again for the help!

John
Fayetteville, GA
1978 Eleganza

John Fredrikson Grand Marais, MN 1978 Eleganza

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Re: [GMCnet] Onan Dies After about 15 min [message #284047 is a reply to message #284046]

Wed, 05 August 2015 15:16

James Hupy

Messages: 6806
Registered: May 2010

Karma: -62

Senior Member

Yes, if you still have points ignition, clean and gap them. Plugs too.
Jim Hupy
On Aug 5, 2015 1:11 PM, "John Fredrikson" wrote:

> It seems that I'm not done troubleshooting my Onan. It will start when
> cold and sun smooth. after about 15 minutes of running it will stumble and
> die.
> I can get it to start again sometimes, but it will only run about 5
> minutes before it dies again and won't start again. Once it has cooled it
> will
> usually start and run for another 10 to 15 minutes.
>
> I have checked the fuel and the new pump seems to be providing plenty of
> fuel. I'm thinking it must be a problem with the ignition. I have tested the
> coil according to the manual (cold) and it looks good. I haven't tested it
> yet just after failure. I will do that next.
>
> Any recommendations on anything else I should look at?
>
> Thanks again for the help!
>
> John
> Fayetteville, GA
> 1978 Eleganza
> --
> John Fredrikson
> Fayetteville, GA
> 1978 Eleganza
>
> _______________________________________________
> 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 Dies After about 15 min [message #284049 is a reply to message #284047]

Wed, 05 August 2015 15:22

Mr ERFisher

Messages: 7117
Registered: August 2005

Karma: 2

Senior Member

Still sounds like fuel

On Wednesday, August 5, 2015, James Hupy wrote:

> Yes, if you still have points ignition, clean and gap them. Plugs too.
> Jim Hupy
> On Aug 5, 2015 1:11 PM, "John Fredrikson"
> wrote:
>
>> It seems that I'm not done troubleshooting my Onan. It will start when
>> cold and sun smooth. after about 15 minutes of running it will stumble
> and
>> die.
>> I can get it to start again sometimes, but it will only run about 5
>> minutes before it dies again and won't start again. Once it has cooled it
>> will
>> usually start and run for another 10 to 15 minutes.
>>
>> I have checked the fuel and the new pump seems to be providing plenty of
>> fuel. I'm thinking it must be a problem with the ignition. I have tested
> the
>> coil according to the manual (cold) and it looks good. I haven't tested
> it
>> yet just after failure. I will do that next.
>>
>> Any recommendations on anything else I should look at?
>>
>> Thanks again for the help!
>>
>> John
>> Fayetteville, GA
>> 1978 Eleganza
>> --
>> John Fredrikson
>> Fayetteville, GA
>> 1978 Eleganza
>>
>> _______________________________________________
>> 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 Dies After about 15 min [message #284050 is a reply to message #284046]

Wed, 05 August 2015 15:29

Jeff Marten

Messages: 199
Registered: August 2013

Karma: 1

Senior Member

Have you checked the choke?

Chuck Norris destroyed the periodic table because he only recognizes the element of surprise..

> Date: Wed, 5 Aug 2015 14:11:23 -0600
> To: gmclist@list.gmcnet.org
> From: jtfred@gmail.com
> Subject: [GMCnet] Onan Dies After about 15 min
>
> It seems that I'm not done troubleshooting my Onan. It will start when cold and sun smooth. after about 15 minutes of running it will stumble and die.
> I can get it to start again sometimes, but it will only run about 5 minutes before it dies again and won't start again. Once it has cooled it will
> usually start and run for another 10 to 15 minutes.
>
> I have checked the fuel and the new pump seems to be providing plenty of fuel. I'm thinking it must be a problem with the ignition. I have tested the
> coil according to the manual (cold) and it looks good. I haven't tested it yet just after failure. I will do that next.
>
> Any recommendations on anything else I should look at?
>
> Thanks again for the help!
>
> John
> Fayetteville, GA
> 1978 Eleganza
> --
> John Fredrikson
> Fayetteville, GA
> 1978 Eleganza
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

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1985 Gulf Stream 34' Sun Stream 1964 Falcon 'Vert 1980 Bradley GTE 1999 Chevy Tahoe 2005 Saab 93 Aero 1987 Suzuki Intruder 1400 1978 Glastron/Carlson CV23

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Re: Onan Dies After about 15 min [message #284051 is a reply to message #284046]

Wed, 05 August 2015 15:39

jtfred

Messages: 132
Registered: January 2015
Location: Grand Marais, MN

Karma: 0

Senior Member

Thanks for the quick replies.

The PO had installed an Onan electronic ignition, so no points.

I had thought fuel initially, but when it failed I pulled the fuel supply to the carb and got good flow so I don't think it is supply. That doesn't mean that it could be carb.

I don't think it is choke. I just watched it die and the choke didn't move as it started to stumble and die.

After it died, I tested the coil again and got the same readings. If that is a good test of the coil, it must be OK.

What next, condensor???

Thanks again,

John

John Fredrikson Grand Marais, MN 1978 Eleganza

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Re: [GMCnet] Onan Dies After about 15 min [message #284054 is a reply to message #284051]

Wed, 05 August 2015 15:58

James Hupy

Messages: 6806
Registered: May 2010

Karma: -62

Senior Member

The Onan electronic ignition is still actuated by the points plunger. Those
things wear. They are made from phenolic resins. Eventually they wear down
and become too short to function. Gary Bovee's ignition is triggered by a
rotating magnet. No pushrod to wear. Nothing actually touches another part.
If it is assembled ACCORDING TO HIS SPECIFIC INSTRUCTIONS, they never
require adjustment for their entire service life. Check for spark.
Jim Hupy
On Aug 5, 2015 1:39 PM, "John Fredrikson" wrote:

> Thanks for the quick replies.
>
> The PO had installed an Onan electronic ignition, so no points.
>
> I had thought fuel initially, but when it failed I pulled the fuel supply
> to the carb and got good flow so I don't think it is supply. That doesn't
> mean that it could be carb.
>
> I don't think it is choke. I just watched it die and the choke didn't move
> as it started to stumble and die.
>
> After it died, I tested the coil again and got the same readings. If that
> is a good test of the coil, it must be OK.
>
> What next, condensor???
>
> Thanks again,
>
> John
> --
> John Fredrikson
> Fayetteville, GA
> 1978 Eleganza
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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Re: Onan Dies After about 15 min [message #284055 is a reply to message #284051]

Wed, 05 August 2015 16:00

A Hamilto

Messages: 4508
Registered: April 2011

Karma: 39

Senior Member

jtfred wrote on Wed, 05 August 2015 15:39

Thanks for the quick replies.
The PO had installed an Onan electronic ignition, so no points.

I had thought fuel initially, but when it failed I pulled the fuel supply to the carb and got good flow so I don't think it is supply. That doesn't mean that it could be carb.

I don't think it is choke. I just watched it die and the choke didn't move as it started to stumble and die.

After it died, I tested the coil again and got the same readings. If that is a good test of the coil, it must be OK.

What next, condensor???

Thanks again,

John

You can try the condenser. If that doesn't fix it, the coil can act like that. Fails when it gets hot.

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Re: Onan Dies After about 15 min [message #284059 is a reply to message #284055]

Wed, 05 August 2015 17:43

tphipps

Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL

Karma: 9

Senior Member

True Electronic Ignition systems do not use a condenser. The condenser in a standard points type ignition system is to prevent the points from burning (pitting). Electronic systems take the load from the points, the points become a simple switch.
Condensers do fail, but in this case, it is probably not the failure that is causing the problem.
From Wikipedia, "The capacitor has two functions. Its main function is to form a series resonant circuit with the ignition coil. During resonance, energy is repeatedly transferred to the secondary side until the energy is exhausted.[2] As a result of this resonance the duration of the spark is sustained and so implements a good flame front in the air/fuel mixture. The capacitor, by default minimizes arcing at the contacts at the point of opening. This reduces contact burning and maximizes point life. The Kettering system became the primary ignition system for many years in the automotive industry due to its lower cost, higher reliability and relative simplicity."
Tom, MS II

2012 Phoenix Cruiser model 2552 KA4CSG

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Re: [GMCnet] Onan Dies After about 15 min [message #284065 is a reply to message #284046]

Wed, 05 August 2015 18:38

Ken Henderson

Messages: 8726
Registered: March 2004
Location: Americus, GA

Karma: 9

Senior Member

John,

If you haven't done so, check the plug gaps. I helped get an Onan running
reliably at Noccalula Falls last weekend. He didn't have the electronic
ignition and the points turned out to be the major problem, but the plug
gaps were also big contributors: They were about 0.080" instead of the
correct 0.020". Ran like a top after we got all the ignition working
right, including correct timing.

The condenser at the ignition coil is for noise suppression and does not
affect the points (it's on the IGN side of the coil). But it CAN cause
your problem -- disconnect it and see if the run time improves.

Ken H.

On Wed, Aug 5, 2015 at 4:11 PM, John Fredrikson wrote:

> It seems that I'm not done troubleshooting my Onan. It will start when
> cold and sun smooth. after about 15 minutes of running it will stumble and
> die.
> I can get it to start again sometimes, but it will only run about 5
> minutes before it dies again and won't start again. Once it has cooled it
> will
> usually start and run for another 10 to 15 minutes.
>
> I have checked the fuel and the new pump seems to be providing plenty of
> fuel. I'm thinking it must be a problem with the ignition. I have tested the
> coil according to the manual (cold) and it looks good. I haven't tested it
> yet just after failure. I will do that next.
>
> Any recommendations on anything else I should look at?
>
> Thanks again for the help!
> ...
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach

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Re: [GMCnet] Onan Dies After about 15 min [message #284068 is a reply to message #284065]

Wed, 05 August 2015 19:18

jtfred

Messages: 132
Registered: January 2015
Location: Grand Marais, MN

Karma: 0

Senior Member

Thanks Ken. I did verify my plug gaps when I was going through my previous troubleshooting. What's strange is that it starts and runs fine for 15 or so minutes then stumbles and dies.

I will check spark as it fails tomorrow to verify that it is ignition and if so, I'll disconnect the condenser to see if that has an impact.

Thanks!

John

John Fredrikson Grand Marais, MN 1978 Eleganza

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Re: Onan Dies After about 15 min [message #284075 is a reply to message #284046]

Wed, 05 August 2015 20:15

jhbridges

Messages: 8412
Registered: May 2011
Location: Braselton ga

Karma: -74

Senior Member

Since I had one fail, Q & D check. Get a can of cold spray (from any electronic parts house), and fire the genset up. When it starts to stumble. frost the ignition module. If it picks back up and runs, replace. If not, the module is probably not the problem.

--johnny

Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell

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Re: Onan Dies After about 15 min [message #284077 is a reply to message #284075]

Wed, 05 August 2015 20:34

jtfred

Messages: 132
Registered: January 2015
Location: Grand Marais, MN

Karma: 0

Senior Member

Johnny Bridges wrote on Wed, 05 August 2015 21:15

Since I had one fail, Q & D check. Get a can of cold spray (from any electronic parts house), and fire the genset up. When it starts to stumble. frost the ignition module. If it picks back up and runs, replace. If not, the module is probably not the problem.

--johnny

Thanks Johnny. I will try to find some cold spray and try that.

Thanks again,

John

John Fredrikson Grand Marais, MN 1978 Eleganza

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Re: [GMCnet] Onan Dies After about 15 min [message #284103 is a reply to message #284077]

Thu, 06 August 2015 07:47

Jim at the Co-op

Messages: 291
Registered: May 2014
Location: Orlando Florida

Karma: 2

Senior Member

Run a jumper wire from 12 volts on the starter to the hot side of the
coil. The electric pump should start right away. Fire up the generator
and see if it shuts down. If not, it's in the alternator circuit or
something in the board, oil pressure circuit... it is not the coil, points
or any of that. Now put in a prime circuit, replace the momentary switch
with a toggle on/off and run it hot wired and forget trying to make that
part of the generator work. A drawing of this prime circuit is on my site
on the "information" page. Good luck,

Jim Bounds

On Wed, Aug 5, 2015 at 9:34 PM, John Fredrikson wrote:

> Johnny Bridges wrote on Wed, 05 August 2015 21:15
>> Since I had one fail, Q & D check. Get a can of cold spray (from any
> electronic parts house), and fire the genset up. When it starts to stumble.
>> frost the ignition module. If it picks back up and runs, replace. If
> not, the module is probably not the problem.
>>
>> --johnny
>
>
>
> Thanks Johnny. I will try to find some cold spray and try that.
>
> Thanks again,
>
> John
> --
> John Fredrikson
> Fayetteville, GA
> 1978 Eleganza
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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Re: Onan Dies After about 15 min [message #284104 is a reply to message #284046]

Thu, 06 August 2015 07:52

jhbridges

Messages: 8412
Registered: May 2011
Location: Braselton ga

Karma: -74

Senior Member

One trade name was 'Freeze Mist", there were several others. They're basically freon in a can. If the EPA has banned the stuff, often trico solvent and a fan will chill the components enough to find a heat sensitive one.

--johnny

Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell

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Re: Onan Dies After about 15 min [message #284113 is a reply to message #284046]

Thu, 06 August 2015 08:56

JohnL455

Messages: 4447
Registered: October 2006
Location: Woodstock, IL

Karma: 12

Senior Member

You may have the "trick" fuel line feature. Close the drawer and it kinks. Open it to work on and she is fine. Close it and it partly kinks, gets worse when hot and soft and you have pinched garden hose syndrome. This one has stumped many a good mechanic. OE there was a spring on the fuel line to dress it as drawer closed. Those have all rusted away by now.

John Lebetski
Woodstock, IL
77 Eleganza II

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Re: Onan Dies After about 15 min [message #284114 is a reply to message #284104]

Thu, 06 August 2015 08:58

Matt Colie

Messages: 8547
Registered: March 2007
Location: S.E. Michigan

Karma: 7

Senior Member

Have you checked the valve lash recently (ever)?
This can happen when lash is too small and the lash goes to Zip, the engine will get rough.
It will only take a minute to cool enough so that valve is down on the seat again.

Matt

Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit

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Re: [GMCnet] Onan Dies After about 15 min [message #284115 is a reply to message #284113]

Thu, 06 August 2015 09:05

Jeff Marten

Messages: 199
Registered: August 2013

Karma: 1

Senior Member

I think you nailed it. Thinking back, mine did the same thing. I ended up using a piece of 2x2 to hold the fuel line in position without kinking as I slid the tray in.

Chuck Norris destroyed the periodic table because he only recognizes the element of surprise..

> Date: Thu, 6 Aug 2015 07:56:26 -0600
> To: gmclist@list.gmcnet.org
> From: gransport7087@gmail.com
> Subject: Re: [GMCnet] Onan Dies After about 15 min
>
> You may have the "trick" fuel line feature. Close the drawer and it kinks. Open it to work on and she is fine. Close it and it partly kinks, gets
> worse when hot and soft and you have pinched garden hose syndrome. This one has stumped many a good mechanic. OE there was a spring on the fuel line
> to dress it as drawer closed. Those have all rusted away by now.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
> Source America First
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

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1985 Gulf Stream 34' Sun Stream 1964 Falcon 'Vert 1980 Bradley GTE 1999 Chevy Tahoe 2005 Saab 93 Aero 1987 Suzuki Intruder 1400 1978 Glastron/Carlson CV23

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Re: [GMCnet] Onan Dies After about 15 min [message #284119 is a reply to message #284103]

Thu, 06 August 2015 10:16

jtfred

Messages: 132
Registered: January 2015
Location: Grand Marais, MN

Karma: 0

Senior Member

Jim at the Co-op wrote on Thu, 06 August 2015 08:47

Run a jumper wire from 12 volts on the starter to the hot side of the
coil. The electric pump should start right away. Fire up the generator
and see if it shuts down. If not, it's in the alternator circuit or
something in the board, oil pressure circuit... it is not the coil, points
or any of that. Now put in a prime circuit, replace the momentary switch
with a toggle on/off and run it hot wired and forget trying to make that
part of the generator work. A drawing of this prime circuit is on my site
on the "information" page. Good luck,

Jim Bounds

Thanks Jim.

It ran about 25 min this morning before it died. I did try the jumper from the 12v on the starter to the hot side of the coil and there was no change.

I picked up an in line spark tester this morning and had that connected. On cold startup I could see a steady spark. When it started to stumble (it starts to miss and slowly gets worse before it dies after about 5 min) I did see the change in the spark. Once it died I would get one strong spark (stronger than when it was running) then nothing. I tried disconnect the condenser which did not fix the problem. I haven't been able to find a can of cold spray to test as Johnny has suggested.

I don't think it is a fuel line kinking issue because this is happening in my driveway with the Onan slid out on the drawer and I did pull the line to check for fuel pressure when I first started to troubleshoot.

I'm thinking it must be the coil. In searching back through the forum, it looks like a Harley Davidson coil is an acceptable replacement. I couldn't find a model number in my searching. Does anyone know of a model number that would be a good replacement?

Thanks for all of your help!

John

John Fredrikson Grand Marais, MN 1978 Eleganza

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Re: Onan Dies After about 15 min [message #284120 is a reply to message #284046]

Thu, 06 August 2015 10:31

jhbridges

Messages: 8412
Registered: May 2011
Location: Braselton ga

Karma: -74

Senior Member

If you can't find a Harley shop, stop off at the parts counter of the many scooter shops around. Most of the heathen chinee scooters use the same coil system. Take the old one to make a fit.

Not to muddy the water too much, but the single spark on power smacks of a lack of switching of the voltage to the coil

--johnny

Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell

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Re: Onan Dies After about 15 min [message #284121 is a reply to message #284120]

Thu, 06 August 2015 10:38

jtfred

Messages: 132
Registered: January 2015
Location: Grand Marais, MN

Karma: 0

Senior Member

Johnny Bridges wrote on Thu, 06 August 2015 11:31

If you can't find a Harley shop, stop off at the parts counter of the many scooter shops around. Most of the heathen chinee scooters use the same coil system. Take the old one to make a fit.

Not to muddy the water too much, but the single spark on power smacks of a lack of switching of the voltage to the coil

--johnny

I think I understand what you are saying, but wouldn't that be ruled out by the jumper from the 12v supply on the starter to the hot side of the coil?

Thanks Johnny!

John Fredrikson Grand Marais, MN 1978 Eleganza

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