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The Onan control panel

Jim Bounds provided an excellent article in the August 1998 issue of GMCMM.  His suggestion was for a Onan primer switch to be added to the control panel of the Onan generator.  His design has been "improved" by adding a diode so that the Onan voltage does not feed back into the 12 volt source.  For those of us that intend to keep the Onan this primer switch will stop the agonizing cranking of the Onan to feed gas to the carburetor.

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Connections to the Onan control panel

The drawing in the article did not match my coach.  I think this was because mine was a later model (77).  I also do not like fuses hidden behind panels so I supplied the 12 volts for the circuit from the Porch Light switch which is already fused.  We tested this concept on Mr.C's coach by making a wiring error  and blowing the fuse.  It worked well.

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Connections to the power from the Porch Switch

 The pictures show the installation and connections for the 1977 model coach.  The theory of operation is that when you push the prime switch 12 volts is applied to the runtime meter, the light in the start switch, and the Onan electric fuel pump.  The result is that fuel is pumped up to the carburetor ( which is usually dry).  Release the prime switch and start the  Onan in the normal way. It starts much faster.
The best way to find the correct connection on the Start/stop switch is to run the Onan and measure until you find the terminal with 12 volts on it with the Onan running.  This is the terminal to attach to the diode.   Note that the stripe on the diode is nearer to the Start/Stop switch. The 12 volt line from the other side of the push button switch I ran down to the bank of switches at the door which has a switch for the porch light.  I tapped into the fused 12 volt line and attached the wire to the push button.

2 amp push button
DIODE Radio Shack RS-2761143 -PK2-3 AMP (PACKAGE OF 2-FIND A FRIEND)  $1.19-(GARY BERRY)
3 feet of wire

Thanks to Mr.c for being the test bed and Gary Berry for the diode information.

SCHEMATIC / WIRING- from bdub's site

The connections are some what different for a Royal. The key is to connect to the plus side of the run time meter.   Here are some pictures by larry, showing the connections: