The Forestry Forum

General Forestry => Sawmills and Milling => Topic started by: jb616 on September 11, 2018, 08:50:29 PM

Title: Wiring the Onan
Post by: jb616 on September 11, 2018, 08:50:29 PM
Does anyone have a wiring diagram for an Onan or an engine with a coil that is dependent on a battery supply and not a magneto? I will be using a key switch to start and run my manual LT30. I know I probably will run the positive battery cable right to the starter solenoid and run a hot wire from the same terminal to the key switch. I will need a momentary hot wire out to the solenoid trigger and a constant hot to the coil and an electric fuel pump but I am not sure how to wire in the charging wire from the voltage regulator so that it doesn't feed right back into the coil and keep it running. 
           Also, is there a spot that i can thread in a mechanical oil pressure gauge on the Onan? It always gives me peace of mind knowing that there is oil pressure when I am running a pressure lubrication motor. 
Title: Re: Wiring the Onan
Post by: sawguy21 on September 11, 2018, 11:16:36 PM
The charging wire can go directly to the battery side of the solenoid, there is no danger of it feeding the coil with the switch off. If you are dding an ignition switch ensure that it the proper one for your application, magneto ignition switch will not work.
Title: Re: Wiring the Onan
Post by: bandmiller2 on September 12, 2018, 07:40:52 AM
A small in line diode will prevent feed back. I have converted many old tractor generators to alternators and those simple cheap diodes have worked well to prevent feed back. Frank C.
Title: Re: Wiring the Onan
Post by: jb616 on September 13, 2018, 05:56:30 PM
are there different size diodes?  not sure what I would need.

Also, does anyone have an answer for a port on the motor for an oil pressure reading?  
Title: Re: Wiring the Onan
Post by: bandmiller2 on September 15, 2018, 06:44:58 AM
JB, I got the diodes from a company that installs emergency lights on police cruisers and fire equip. no rating on them. I would go to one of those you do it electronic stores and give them a estimate of the amps and voltage. I don't think bigger would hurt their not costly anyways. Frank C.
Title: Re: Wiring the Onan
Post by: jb616 on September 17, 2018, 08:24:01 PM
As I was looking at the wiring on the motor today, i noticed that the condenser was on the positive terminal of the coil. On my Kohlers, it is on the negative. Is this correct?  I believe that it is an electronic ignition with no points as it is a mid to late 1990's motor. 
Title: Re: Wiring the Onan
Post by: sawguy21 on September 18, 2018, 12:26:17 AM
If electronic it won't need a condenser. I wonder if somebody who didn't understand ignition systems added it.  On a breaker system the condenser is wired to thee same side of the coil as the points.
Title: Re: Wiring the Onan
Post by: sparks on September 18, 2018, 05:03:09 PM
Condenser is on there to stop noise that could affect the power feed board. It goes on the + terminal of the coil.
The coil + terminal needs a 12volt source from a key on connection and the red wire from the ignition module.
The coil - terminal needs the wire from the ignition module under the flywheel.

Attached is the wiring diagram normally used by Onan.
Title: Re: Wiring the Onan
Post by: jb616 on September 19, 2018, 01:48:03 PM
Quote from: sparks on September 18, 2018, 05:03:09 PMCondenser is on there to stop noise that could affect the power feed board. It goes on the + terminal of the coil. The coil + terminal needs a 12volt source from a key on connection and the red wire from the ignition module. The coil - terminal needs the wire from the ignition module under the flywheel. Attached is the wiring diagram normally used by Onan.


Awesome information, thanks a lot Sparks.  Is there a key switch part number that I can use?  there are so many out there that I want to get the one I need. thanks again!
Title: Re: Wiring the Onan
Post by: Jim_Rogers on September 20, 2018, 02:45:39 PM

QuoteIs there a key switch part number that I can use?

You could/should be calling WM parts and asking them.
I did when my key switch died the first time and they gave me several parts numbers for different companies. I used the napa number and get that one each time my switch acts up.
I have written several stories here (I believe) about changing my key switch. You could also update your profile to show your mill model and it will show up in your signature.
Jim Rogers
Title: Re: Wiring the Onan
Post by: sparks on September 21, 2018, 02:10:22 PM
Universal Ignition Switch - US2806 Massey Ferguson Tractor Ignition Switches