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trouble with on board onan

gitpicker2009
Explorer
Explorer
hey ya'll, my onan 2500 in my 2012 Arctic Fox will NOT start.
It's got about 200 hours on it, so I thought maybe I'd change the spark plug, but I can't get to it. I think I'm going to have to actually remove the generator through the bottom of the coach!
Has anyone dealt with this before? Any tips/tricks would be appreciated.

Anthony
23 REPLIES 23

mellow
Explorer
Explorer
Had issues with mine due to the propane cord was kinked in the propane closet. I would try spraying it LIGHTLY with starter fluid to see if it kicks over then you can go from there. It isn't to bad to drop them if you need to, just read up on how its done. Take the cover off the air filter but leave the filter on and try a quick spray to see if it does anything. If it does then you have a fuel issue.
2002 F-350 7.3 Lariat 4x4 DRW ZF6
2008 Lance 1191 - 220w of solar - Bring on the sun!

vern_kelly
Explorer
Explorer
I have a 2500 Onan in my 1998 Lance. I've run across a couple problems starting. One is not a good charge on the battery. It will turn over the generator but the spark is insufficient to ignite and run. I've done that a couple times. 2nd is running out of propane. Takes quite a while to get propane to the generator.

I try to run it every month to 6 weeks.
1998 2500 Dodge V10 3.55 Quad cab. Lance 5000 camper 9'10" and tow 17.5 ft Larson Boat

Neal47
Explorer
Explorer
Had the same problem. A wasp had built a nest in the propane vent hose that comes off the carburetor. They are attracted to the smell of propane. Cleaned out the hose and it started right up. I put a screen over the end of the vent hose and no more problems.

jp3731
Explorer
Explorer
I had a similar problem with my Generac that's in my 2002 Lance. It turned out that the diaphragm in the vaporizer was stuck. Opened up the lp vaporizer cleaned the diaphragm and no problems since.
1997 F350 CC PSD DRW. 2002 Lance 1130.

bighatnohorse
Explorer II
Explorer II
mkasner wrote:
There is a little retention spring on the arm that keeps the throttle from shutting off. Had the same issue happen on mine and the Onan tech just moved the spring from the back hole to the front hole. Yes I know pictures, ill have to go digging


Yes. Check this. Also, remove the wires to the low pressure oil switch and jumper (short) them to each other. It's quite common on many types of generators for the low oil switch to fail.

And, there is mechanical linkage on the carburator that can "stick" but still allow it to fire and turn over once or twice. My bet would be on the low oil pressure switch failure.
2021 Arctic Fox 1150
'15 F350 6.7 diesel dually long bed
Eagle Cap Owners
“The best lack all conviction, while the worst
Are full of passionate intensity."
-Yeats

D_E_Bishop
Explorer
Explorer
We had a 4000 in our Bounder and it was a delight, start and run and run and run. Forget how many hours, a lot.

The Winnie is a 5500, had 550 hours on it and quit, I spent $2300 to get it fixed. The armature bearings were bad and a tune up etc. Ran about 4 hours and quit. Turns out the armature bearing was pressed on too far and brush on one slip ring got onto the phenolic slip ring assemble and lost power to the sensor and shut down.

Brand new armature from Onan, defective, maybe it's the design, it's a Code A generator, that means it is the first year of production, or maybe it was just QA at the factory.

Hope to get it back tomorrow but most likely next week.

The Champion 2000 runs great. Too bad it won't run the residential appliances our rig came with.
"I travel not to go anywhere, but to go. I travel for travel's sake. The great affair is to go". R. L. Stevenson

David Bishop
2002 Winnebago Adventurer 32V
2009 GMC Canyon
Roadmaster 5000
BrakeBuddy Classic II

Bedlam
Moderator
Moderator
gitpicker2009 wrote:
Jimh425

It cranks, but no start. I've checked the propane, tanks are half full and open, stove works. Just no startup.

Pull the spark plug wire off the plug and use a second plug with the threads grounded against the the generator frame. Cranking the starter at the generator should produce spark. If it does not you have ignition problems. If it does, it is fuel delivery or a bad spark plug which you now to access and replace.

Since this generator runs on propane, it will not gum up and tarnish like those running on ethanol mixed gasoline. I would check the fuel solenoid for power when trying to crank the engine before digging any deeper into the fuel system.

Host Mammoth 11.5 on Ram 5500 HD

Bedlam
Moderator
Moderator
Sorry about the link. You may have to register for free on the site to access the truck camper section. Paid memberships get access to other content - You can decide whether it has any value. This is an owner run Northwood Mfg. site I visited when I had my Arctic Fox 811.

Host Mammoth 11.5 on Ram 5500 HD

gitpicker2009
Explorer
Explorer
Hey Bedlam, thanks for the link, but it says I'm not authorized to view that page.

gitpicker2009
Explorer
Explorer
Jimh425

It cranks, but no start. I've checked the propane, tanks are half full and open, stove works. Just no startup.

jimh406
Explorer III
Explorer III
gitpicker2009 wrote:
It's been about 2 months since I ran it. I actually do try to go out every month or so and fire it up per instructions with a load on it.
Last time I tried, no go.


What are your symptoms and what did you check?

'10 Ford F-450, 6.4, 4.30, 4x4, 14,500 GVWR, '06 Host Rainer 950 DS, Torklift Talon tiedowns, Glow Steps, and Fastguns. Bilstein 4600s, Firestone Bags, Toyo M655 Gs, Curt front hitch, Energy Suspension bump stops.

NRA Life Member, CCA Life Member

Bedlam
Moderator
Moderator
More information on sparkplug access can be found here:

http://www.nroa2003.com/forum/forum/message-board/truck-campers/265472-spark-plug-change-onan-2500-i...

Host Mammoth 11.5 on Ram 5500 HD

gitpicker2009
Explorer
Explorer
It's been about 2 months since I ran it. I actually do try to go out every month or so and fire it up per instructions with a load on it.
Last time I tried, no go.
The biggest problem is, as far as I can see there is NO way to get to the spark plug, to even check it.

Bedlam
Moderator
Moderator
I’m on my third RV with an Onan that runs without issues.

Host Mammoth 11.5 on Ram 5500 HD