Wiring new Onan Switch

[shawn bennear]

So many projects... Got this from a friend who was going to toss it. He never used it. That scratch on the hour meter was too much for him to handle
apparently...lol.
I would like to wire it up, as I do believe my switch is bad, but have no wiring diagrams. I installed the little prime button in the panel, but need
to figure out how to wire this in. Has anyone put the same one on?

--
http://www.gmcmotorhomeworld.com

1977 Palm Beach, 403 V8 w headers.

 

[jim kanomata1]

Hate to be a smart ass, but we have the info and we will look it up and
send it to you n/c as we stock most everything and gotten to be the major
supplier as we help lot of people.
Just send me your email to jimk

On Sat, Apr 18, 2020 at 4:02 PM Shawn Bennear via Gmclist <

> So many projects... Got this from a friend who was going to toss it. He
> never used it. That scratch on the hour meter was too much for him to handle
> apparently...lol.
> I would like to wire it up, as I do believe my switch is bad, but have no
> wiring diagrams. I installed the little prime button in the panel, but need
> to figure out how to wire this in. Has anyone put the same one on?
>
>
>
>
> --
> http://www.gmcmotorhomeworld.com
>
> 1977 Palm Beach, 403 V8 w headers.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502

 

[john r. lebetski]

Trace the wires to the Onan board
Pin 1 stop
Pin 2 grd
Pin 3 start
Pin 5 lamp/run time.
You’ll have to meter out the new switch as I assume one is lamp in
Primer is not factory on our coaches so you’ll have to read some of the write ups on that. I don’t have it, don’t need it, don’t want it.

--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[Bruce Hart]

Jim Bounds has a write-up on installing the prime switch.

On Sun, Apr 19, 2020 at 4:29 PM John R. Lebetski via Gmclist <

> Trace the wires to the Onan board
> Pin 1 stop
> Pin 2 grd
> Pin 3 start
> Pin 5 lamp/run time.
> You’ll have to meter out the new switch as I assume one is lamp in
> Primer is not factory on our coaches so you’ll have to read some of the
> write ups on that. I don’t have it, don’t need it, don’t want it.
>
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class

 

[Bruce Hart]

Found the write up

http://bdub.net/gmcmotorhome.info/onan.htm

> Jim Bounds has a write-up on installing the prime switch.
>
> On Sun, Apr 19, 2020 at 4:29 PM John R. Lebetski via Gmclist <

>
>> Trace the wires to the Onan board
>> Pin 1 stop
>> Pin 2 grd
>> Pin 3 start
>> Pin 5 lamp/run time.
>> You’ll have to meter out the new switch as I assume one is lamp in
>> Primer is not factory on our coaches so you’ll have to read some of the
>> write ups on that. I don’t have it, don’t need it, don’t want it.
>>
>> --
>> John Lebetski
>> Woodstock, IL
>> 77 Eleganza II
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
> --
> Bruce Hart
> 1976 Palm Beach
> Milliken, Co
> GMC=Got More Class
>
>

--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class

 

[RF_Burns]

That link is a very good write-up on the Prime button circuit.

http://bdub.net/gmcmotorhome.info/onan.htm

I'd like to add a couple things:
-First the Diode is not really needed because the power source for the Onan control board is one and the same. (unless you have an early coach with a
small Onan starter battery... at which time I would consider eliminating this)

-Second, you may find the Onan starts easier if you continue to HOLD the Prime button while cranking and until the engine comes up to speed. The
reason being is the Prime button simply supplies power to the junction of the Ignition coil and Fuel pump. When the engine starts, the Control Board
disables the starter and pulls in the Run relay to provide power to the Coil and Fuel Pump. However the Run relay may not pull in fast enough and the
engine dies. Holding the Prime button provides constant Coil and Fuel Pump power throughout the startup. When the engine is up to speed, then release
the Prime Button and the RUN relay will provide power to keep the engine running.

Just my experience.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[johnny]

Consider if you w3ill. The idea of a prime button is correcting a symptom without addressing the cause of the problem. If the fuel system is working
correctly - shutoff solenoid works, pump works correctly, etc, there's no need for it. The set should spin off quickly if it's run regularly. We
never needed one on the sets we used regularly in promotions vans where they were run three or four times a week.
If the set sits forever, or has air leaks in the line or a bad solenoid or pump, then the prime button will make it crank quicker if it's gonna crank
at all.

--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

 

[john r. lebetski]

Be aware there seems to be a discrepancy on various drawings on 1, 2, and 3 on the board and the functions. Unless I’m reading them wrong.
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[RF_Burns]

Johnny,
Thing is, most no longer have the fuel shut-off solenoid and most don't get run regularly. So the carb is dry and the fuel pump needs to prime itself
and fill the carb bowl. I Googled to find the cost of a fuel shut-off solenoid and didn't find one under $100 bucks unless it was manual. I'm sure
spending a bit more time I could come up with something cheaper.

Mine may sit for months without the generator running. Yes I know they say run it once a month, but I'm not starting up the coach to get it outside
the shop so I can run the generator for 30 minutes each month.

So for a cheap switch and 15 minutes time you have a fix.

Interestingly over at GMCMHForm.com a guy just posted a newer style Onan remote control panel. Guess what it has.. a PRIME function on the switch!

And when I got my 2018 GMC pickup, I noticed a noise for 3 seconds or so every morning when I opened the door. Guess what it is?? Its the fuel pump
running. For an improved customer experience, GM has added a PRIME function. After the truck has been sitting for a period of time (overnight) when
you open the driver's side door, the fuel pump runs for a few seconds to PRIME the fuel system... and this is EFI!

Just my experience.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that