| ONAN Generator [message #356816] |
Wed, 15 July 2020 15:39  |
 |
Samuel Ferguson
Messages: 107
Registered: September 2019
Location: Pittsfield, Illinois
Karma: 0
|
Senior Member |
|
|
Can an ONAN generator jump timing?
Replaced the fuel line from fuel pump to carb. Generator is hard to start. When engine does start up, engine is "very sluggish". Left spark plug is getting hot. Right spark plug is barely warm. I check the spark on the right plug and there is a spark.
Samuel Ferguson
Summer Hill, Illinois
(West Central Illinois)
1976 GMC Palm Beach
|
|
|
|
| Re: [GMCnet] ONAN Generator [message #356819 is a reply to message #356816] |
Wed, 15 July 2020 15:50  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
I'd be looking to see what's happened to the fuel mixture to the right
bank. I'm not positive, but I don't think it's possible for the valve
timing to be different between the cylinders, and the spark timing
absolutely cannot.
Ken H.
On Wed, Jul 15, 2020 at 4:39 PM Samuel Ferguson via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Can an ONAN generator jump timing?
> Replaced the fuel line from fuel pump to carb. Generator is hard to start.
> When engine does start up, engine is "very sluggish". Left spark plug is
> getting hot. Right spark plug is barely warm. I check the spark on the
> right plug and there is a spark.
> --
> Samuel Ferguson
> Pittsfield, Illinois
> (West Central Illinois)
> 1976 GMC Palm Beach (A newbie who will not allow this thing to kick my
> butt!!)
>
> _______________________________________________
> 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
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
| Re: [GMCnet] ONAN Generator [message #356820 is a reply to message #356819] |
Wed, 15 July 2020 16:21 |
|
Samuel Ferguson
Messages: 107
Registered: September 2019
Location: Pittsfield, Illinois
Karma: 0
|
Senior Member |
|
|
This all started when I noticed the fuel line leaking! What I thought was going to be a "simple" install of a new fuel line, took a turn to develop more of a headache!!!! The generator purred like a kitten prior to replacing the fuel line! After installing new fuel line, engine is being difficult in starting. Once it finally starts, it will not idle up or govern the rpm's.
I pulled the spark plugs out and appears it is getting fuel to the plugs. Both plugs appeared to be firing.
Fuel mixture to right bank - Where should I focus to determine this?
Samuel Ferguson
Summer Hill, Illinois
(West Central Illinois)
1976 GMC Palm Beach
[Updated on: Wed, 15 July 2020 17:25] Report message to a moderator |
|
|
|
|
|
|
|
| Re: [GMCnet] ONAN Generator [message #356829 is a reply to message #356825] |
Wed, 15 July 2020 19:53 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
|
Senior Member |
|
|
Have you tried running the generator from a fuel bottle? If you want to
rule out fuel supply issues from your genny I would rig up a plastic bottle
with a fuel hose straight to the carb where the line exiting the pump
attaches and then hang the tank a couple feet above the carb and see if
conditions change. You can make one out of a water bottle fairly easily and
hang it from the window channel. Don’t forget to take the water bottle cap
off when running. If supply has already been verified I apologize.
Sully
Bellevue wa
On Wed, Jul 15, 2020 at 3:38 PM Samuel Ferguson via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Pulled the carb and took apart to clean. Put carb back together and made
> no difference.
> --
> Samuel Ferguson
> Pittsfield, Illinois
> (West Central Illinois)
> 1976 GMC Palm Beach (A newbie who will not allow this thing to kick my
> butt!!)
>
> _______________________________________________
> 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
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
|
|
|
|
|
|
| Re: ONAN Generator [message #356831 is a reply to message #356816] |
Wed, 15 July 2020 21:30 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
|
Senior Member |
|
|
Swap the plugs (Left to right and right to left) then try again. See if the heat problem moves with the plug.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
|
|
|
|
| Re: [GMCnet] ONAN Generator [message #356832 is a reply to message #356831] |
Wed, 15 July 2020 23:33 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
|
Senior Member |
|
|
Typically if you have a new condition after you have made a change the
change is likely related to something you did. Correlation does not assure
causation but it’s the best place to start. You did not answer the drawer
question. My second thought was that in moving the drawer you exposed a bad
electrical connection when the wire loom got tugged with the drawer
movement. The molex plug or other bad connection would likely be the next
place I would look. do you have Duane Simmons Oman diagnostic info? I had
never touched a generator on anything before and by following HIS
diagnostic flowchart had mine working perfectly. I would go there first.
It’s only like two printed pages.
Sully
Bellevue. Wa
On Wed, Jul 15, 2020 at 7:31 PM Ken Burton via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Swap the plugs (Left to right and right to left) then try again. See if
> the heat problem moves with the plug.
>
>
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> 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
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
|
|
|
|
| Re: ONAN Generator [message #356833 is a reply to message #356816] |
Thu, 16 July 2020 00:34 |
Rick Staples
Messages: 126
Registered: May 2014
Location: Johnstown, Colorado, USA
Karma: -1
|
Senior Member |
|
|
Following the old axiom that if it was OK before doing something, then something that was done probably did it. I would carefully check the fuel line from coach to fuel pump. It is long so the genset can slide out on its drawer, and sometimes becomes kinked. I fussed with this when I replaced my Onan's fuel pump a couple of years ago. Observe the fuel hose as the Onan is slid in and out, or at least at several points along its travel. The original hose is clear plastic, and might be getting old and more prone to kinking.
HTH,
Rick Staples
Rick Staples, '75 Eleganza, Johnstown, CO
"Advice is a dangerous gift, even from the Wise to the Wise, and all paths may run ill." -Tolkien
|
|
|
|
| Re: ONAN Generator [message #356876 is a reply to message #356816] |
Fri, 17 July 2020 07:37 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
|
Senior Member |
|
|
I can think of nothing in the Molex or control card that would affect only one cylinder. Your description of a 'hot' side makes me think one cylinder is running lean. how that happens is strange, but mine once started that way - one cylinder firing, the other sputtering. Pulling and releasing the choke rod fixed it, I never figured out what caused it. A compression check is in order though. I take it all the covers and seals including the oil filter seal are in place.
--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
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
