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.
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.
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.
SUPPLIES
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
http://www.bdub.net/OnanPrimeCircuit.gif
http://www.bdub.net/manuals/onanmanual.pdf
WIRING FOR A ROYAL
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:
http://www.gmcmhphotos.com/photos/showgallery.php?cat=3792
Gene
