Home » Public Forums » GMCnet » [GMCnet] Onan not firing, but turns over great
| [GMCnet] Onan not firing, but turns over great [message #324980] |
Sun, 15 October 2017 17:34  |
Luke Walling
Messages: 27
Registered: July 2017
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Junior Member |
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Hi All,
I’ve begun working on the 78.
Now that I’ve replaced the 7 year old golf cart batteries I am starting to work on the electrics. The generator turns over smooth as silk and has what looks like fresh fluids in it. It doesn’t get fuel, and has a little aftermarket fuel shutoff valve inline. The prior owner reports it ran though I suspect this is 4-6 years ago.
I’ve friction fed it fuel, and it certainly feeds it in. But.. alas, no fire. Checked plugs (which don’t look too used, just a bit of carbon on their tips).
I do notice a module with wires removed that look to have been hooked up and leading back towards the ignition system and motherboard.
Any tips on if this could be the cause, where to start?
https://www.dropbox.com/s/x3w8xbhwkraz8mx/2017-10-15%2017.54.13.jpg?dl=0
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| Re: [GMCnet] Onan not firing, but turns over great [message #324981 is a reply to message #324980] |
Sun, 15 October 2017 18:13  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Those wires by the heat sink (voltage reg) are disconnected because 78s do not have a lawn tractor battery. You crank off house bank and charge it via 125 AC to 12VDC converter. However you are missing one wire in that mess. There are supposed to he two wires on a faston twofer still connected and taped up and a single wire taped up. Otherwise you won't have run voltage to the board. Untape those and show picture and look for one more disconnected wire.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] Onan not firing, but turns over great [message #324982 is a reply to message #324980] |
Sun, 15 October 2017 18:26 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Luke Walling wrote on Sun, 15 October 2017 18:34Hi All,
I've begun working on the 78.
Now that I've replaced the 7 year old golf cart batteries I am starting to work on the electrics. The generator turns over smooth as silk and has what looks like fresh fluids in it. It doesn't get fuel, and has a little aftermarket fuel shutoff valve inline. The prior owner reports it ran though I suspect this is 4-6 years ago.
I've friction fed it fuel, and it certainly feeds it in. But.. alas, no fire. Checked plugs (which don't look too used, just a bit of carbon on their tips).
I do notice a module with wires removed that look to have been hooked up and leading back towards the ignition system and motherboard.
Any tips on if this could be the cause, where to start? <snip the picture>
Luke,
The disconnected module is a charging voltage regulator that you do not need as the converter should be charging the house bank when the Onan is running.
Did you do the jumper 5 to 9 and check for fuel delivery?
Also, the spark - at best - is barely visible in daylight. If it still has points, clean them.
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 not firing, but turns over great [message #324985 is a reply to message #324982] |
Sun, 15 October 2017 21:02 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Try a little shot of starting fluid. If you have spark, it will start and run on it until it is used up. If it starts with the starting fluid, look for the fuel problem. As Matt suggested, jumper pins 5 to 9 on the control board. You should hear the fuel pump run.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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| Re: [GMCnet] Onan not firing, but turns over great [message #324986 is a reply to message #324985] |
Sun, 15 October 2017 21:04 |
Luke Walling
Messages: 27
Registered: July 2017
Karma: 0
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Junior Member |
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No fire ;(. I filled the bowl with fuel— plugs are soaked.
Will fiddle with the pump separately haven’t tested it alone yet as the fuel like is clear plastic and brittle, need to run all new stuff.
Thanks All
On Sun, Oct 15, 2017 at 10:02 PM -0400, "Carl Stouffer" wrote:
Try a little shot of starting fluid. If you have spark, it will start and run on it until it is used up. If it starts with the starting fluid, look
for the fuel problem. As Matt suggested, jumper pins 5 to 9 on the control board. You should hear the fuel pump run.
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member
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| Re: [GMCnet] Onan not firing, but turns over great [message #324992 is a reply to message #324980] |
Mon, 16 October 2017 08:09 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Wet sparking plugs suggest no spark. Try the 5 - 9 jumper and see if it fires. If not, coil or wires or wiring error (Loose or broken). Check the fuse on the control card. It's a 5 Amp, if it's blown determine why - usually a chafed or loose wire.
--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: [GMCnet] Onan not firing, but turns over great [message #324996 is a reply to message #324980] |
Mon, 16 October 2017 10:34 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Like Terry says. Long periods of inactivity on Onan engines will nearly
always result in some slight corrosion in the contact breakers. A points
file or in lieu of that a fingernail file, NOT AN EMERY BOARD OR SANDPAPER,
a few quick strokes through the closed points followed by a business card
to clean the residue should restore the points. A quick visual check to
verify that the points are actually opening, and you should at least have
spark. If that is not the case, save trouble down the road and install one
of Gary Bovee's electronic ignitions. Set it right, and forgetaboutit.
Jim Hupy
Salem, Or
On Oct 16, 2017 6:42 AM, "Terry" wrote:
Clean the points. Check for fire by shorting them with a screwdriver when
you are cleaning them.
--
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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| Re: [GMCnet] Onan not firing, but turns over great [message #325005 is a reply to message #324996] |
Mon, 16 October 2017 13:46 |
Luke Walling
Messages: 27
Registered: July 2017
Karma: 0
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Junior Member |
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Just fired up the Onan! Still have to sort fuel line and pump issues, used gravity feed and a little external fuel.
The problems were easy - points were nice and new but corroded at the contacts, and ironically the fuse was good but the contacts on the board corroded too not allowing the circuit to close.
Cleaned up those things and she started right up and idled nice!
More to come as I try to figure out the fuel pump circuit problems.
On Mon, Oct 16, 2017 at 11:34 AM -0400, "James Hupy" wrote:
Like Terry says. Long periods of inactivity on Onan engines will nearly
always result in some slight corrosion in the contact breakers. A points
file or in lieu of that a fingernail file, NOT AN EMERY BOARD OR SANDPAPER,
a few quick strokes through the closed points followed by a business card
to clean the residue should restore the points. A quick visual check to
verify that the points are actually opening, and you should at least have
spark. If that is not the case, save trouble down the road and install one
of Gary Bovee's electronic ignitions. Set it right, and forgetaboutit.
Jim Hupy
Salem, Or
On Oct 16, 2017 6:42 AM, "Terry" wrote:
Clean the points. Check for fire by shorting them with a screwdriver when
you are cleaning them.
--
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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| Re: [GMCnet] Onan not firing, but turns over great [message #325006 is a reply to message #325005] |
Mon, 16 October 2017 14:05 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Luke, that Onan should not idle. It should run at the governed speed that
produces 50-60 hertz and around 124-130 volts AC at no load. Somewhere
around 1750 rpm. Might sound like idle speed compared to a Honda or other
late model generators. DO NOT REV IT UP BY PULLING ON THE GOVERNOR LINKAGE
WHILE UNDER LOAD, IT WILL FRY WHATEVER IS PLUGGED INTO IT.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Oct 16, 2017 11:47 AM, "Luke Walling" wrote:
> Just fired up the Onan! Still have to sort fuel line and pump issues,
> used gravity feed and a little external fuel.
>
> The problems were easy - points were nice and new but corroded at the
> contacts, and ironically the fuse was good but the contacts on the board
> corroded too not allowing the circuit to close.
>
> Cleaned up those things and she started right up and idled nice!
>
> More to come as I try to figure out the fuel pump circuit problems.
>
>
>
>
> On Mon, Oct 16, 2017 at 11:34 AM -0400, "James Hupy" > wrote:
>
>
> Like Terry says. Long periods of inactivity on Onan engines will nearly
> always result in some slight corrosion in the contact breakers. A points
> file or in lieu of that a fingernail file, NOT AN EMERY BOARD OR SANDPAPER,
> a few quick strokes through the closed points followed by a business card
> to clean the residue should restore the points. A quick visual check to
> verify that the points are actually opening, and you should at least have
> spark. If that is not the case, save trouble down the road and install one
> of Gary Bovee's electronic ignitions. Set it right, and forgetaboutit.
> Jim Hupy
> Salem, Or
>
> On Oct 16, 2017 6:42 AM, "Terry" wrote:
>
> Clean the points. Check for fire by shorting them with a screwdriver when
> you are cleaning them.
> --
> Terry Kelpien
>
> ASE Master Technician
>
> 73 Glacier 260
>
> Smithfield, Va.
>
>
> _______________________________________________
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| Re: [GMCnet] Onan not firing, but turns over great [message #325007 is a reply to message #325006] |
Mon, 16 October 2017 14:28 |
Luke Walling
Messages: 27
Registered: July 2017
Karma: 0
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Junior Member |
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Probably a poor choice of words.
Don’t have the tools to tell the rpm, however, outlets inside giving 112-115 volts pretty consistently.
Luke
On Mon, Oct 16, 2017 at 3:06 PM -0400, "James Hupy" wrote:
Luke, that Onan should not idle. It should run at the governed speed that
produces 50-60 hertz and around 124-130 volts AC at no load. Somewhere
around 1750 rpm. Might sound like idle speed compared to a Honda or other
late model generators. DO NOT REV IT UP BY PULLING ON THE GOVERNOR LINKAGE
WHILE UNDER LOAD, IT WILL FRY WHATEVER IS PLUGGED INTO IT.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Oct 16, 2017 11:47 AM, "Luke Walling" wrote:
> Just fired up the Onan! Still have to sort fuel line and pump issues,
> used gravity feed and a little external fuel.
>
> The problems were easy - points were nice and new but corroded at the
> contacts, and ironically the fuse was good but the contacts on the board
> corroded too not allowing the circuit to close.
>
> Cleaned up those things and she started right up and idled nice!
>
> More to come as I try to figure out the fuel pump circuit problems.
>
>
>
>
> On Mon, Oct 16, 2017 at 11:34 AM -0400, "James Hupy" > wrote:
>
>
> Like Terry says. Long periods of inactivity on Onan engines will nearly
> always result in some slight corrosion in the contact breakers. A points
> file or in lieu of that a fingernail file, NOT AN EMERY BOARD OR SANDPAPER,
> a few quick strokes through the closed points followed by a business card
> to clean the residue should restore the points. A quick visual check to
> verify that the points are actually opening, and you should at least have
> spark. If that is not the case, save trouble down the road and install one
> of Gary Bovee's electronic ignitions. Set it right, and forgetaboutit.
> Jim Hupy
> Salem, Or
>
> On Oct 16, 2017 6:42 AM, "Terry" wrote:
>
> Clean the points. Check for fire by shorting them with a screwdriver when
> you are cleaning them.
> --
> Terry Kelpien
>
> ASE Master Technician
>
> 73 Glacier 260
>
> Smithfield, Va.
>
>
> _______________________________________________
> 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
>
> _______________________________________________
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| Re: [GMCnet] Onan not firing, but turns over great [message #325009 is a reply to message #325007] |
Mon, 16 October 2017 15:58 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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Luke Walling wrote on Mon, 16 October 2017 15:28Probably a poor choice of words.
Don't have the tools to tell the rpm, however, outlets inside giving 112-115 volts pretty consistently.
Luke
Luke,
I have no idea where you are located, but if it is near any civilization, go look for and get any version of a Kill-A-Watt. At most it will be 30$us. It will tell you the output voltage and the frequency that the Onan is running. Carry that and enough extension cord so you can get it near the Onan while you are adjusting it and you will never be out in the weeds.
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 not firing, but turns over great [message #325025 is a reply to message #324980] |
Mon, 16 October 2017 22:10 |
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Jerry Sitzlar
Messages: 206
Registered: February 2013
Location: Lenoir City, TN
Karma: 4
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Senior Member |
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Any Harbor Freight carries the original Kill-A-Watt. It's $24.95 and if you have a 20% coupon , you get it for $19.95. I use it to adjust and monitor my Onan for voltage and frequency.
Jerry
Jerry Sitzlar..... 77 Eleganza II, Twin bed, dry bath...... Lenoir City, TN (near Knoxville)
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