ONAN Generator

Sketch4u

Sketch4u

New member
Sep 9, 2019
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Pittsfield, Illinois (Pike County - Deer Hunting C
Found fuel line from fuel filter canister to fuel bowl leaking. Replaced the fuel line and generator acts as if it is starving for fuel. Help!!!!!!
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
 
Do you mean the braided line between the pump and carb?? Is tgat is not leaking, perhaps you disturbed the fuel hose feeding the pump from the pass
through fitting on the drawer tray. Those often kink and partly pinch off when drawer is closed giving your symptoms. I replaced with nee Tygon
hose.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
Yes the braided hose. Fuel line behind generator is fine. I unhook the new hose I put on and made I had fuel coming to the put and if does. I put new
hose on and acts as though it is starving. Purred like a kitten before I changed hoses. I did notice one of the fittings has a little bit smaller of a
pass-through than the compression fitting end. Would this make a difference in flow?
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
 
check the float bowl needle valve for hose pieces.
--
1977 Kingsley 455 as stock as it gets except lots of Ragusa parts
 
I’m confused with your diagnosis. The braided line is coming from the pump not to it , Slightly smaller is still way bigger than needle/ seat flow
at inlet to carb so should not restrict.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
Perhaps you knocked loose some old thread compound or dirt by replacing that hose and it has partly restricted the inlet seat of carb.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
Sir, I have occasionally have had rubber lines made at places like Royal Brass for brake and fuel lines. I always blow shop air thru the line before
installing as sometimes a ball of rubber blows out from shop installing the ends.

> Yes, braided line coming from pump to carb. Sorry

--
C. Boyd
76 Crestmont
East Tennessee
 
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!!)
 
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 <

> 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
>
 
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! 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
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
 
> 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! 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,

If the carburetor is so far off that it is leaking wet fuel into the intake stream, that fuel can decide which stream it want to go with and it will.
I suggest that you take a quick look into the carburetor.

It also could be that there is a chip of carbon under one valve so that side has lower compression.

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

> 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
>
 
The bowl is filling with fuel. I found that (if looking at the generator), the left plug is getting hot while the right plug is only getting warm to
the touch. Checking the spark, both plugs are sparking when hitting the start switch. I plan to check the points to make sure they are gapped
properly. 
--
Samuel Ferguson
Pittsfield, Illinois
(West Central Illinois)
1976 GMC Palm Beach (A newbie who will not allow this thing to kick my butt!!)
 
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
 
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 <

> 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
>
 
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
 
I've never seen a clear gas line to the Onan. Or any other location in a GMC. Some clears are rated for gas. Some are not. I'd get it out if it was mine. For me. I have to see ( gas) printed on the outside of any hose that I'd install. As a gas line. It's my Comfort Zone thing.
Bob Dunahugh
 
Get rid of that clear fuel line, and replace it with Gates Barricade Hose
rated for fuel with alcohol in it. Nothing else.
Jim Hupy
Salem, Oregon

On Thu, Jul 16, 2020, 9:18 AM Bob Dunahugh via Gmclist <

> I've never seen a clear gas line to the Onan. Or any other location in a
> GMC. Some clears are rated for gas. Some are not. I'd get it out if it was
> mine. For me. I have to see ( gas) printed on the outside of any hose that
> I'd install. As a gas line. It's my Comfort Zone thing.
> Bob Dunahugh
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
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