I know this is a garden tractor but!

LK3054KIOTI · Nov 20, 2007

hey all I have a Ingersoll 4018 with a Onan engine with 340hrs on the clock but the charging system is not working, ideas? where would I find a wiring schematic for this and how to check it out. HELP!

BTDT · Nov 20, 2007

I think Stuart&Stevenson handles Onan, might check with them or a motorhome dealer/repair facility. Good luck with your search.

2manyrocks · Nov 21, 2007

The few responses may be because not many of us are familiar with this Onan. If it is like a Kohler setup, there would be a stator inside the flywheel that produces unregulated AC voltage which then runs through a rectifier/regulator on the outside of the engine.

You'd just need a voltmeter to check the voltage going into and coming out of the regulator. If you don't have any volts, then use the continuity feature of the voltmeter to see if you have some broken wires.

But the first place would be to check the battery to make sure it's good. The next thing would be to look at the wiring to be sure everything is connected.

I would think you could buy an Onan service manual which would be good to have anyway.

wushaw · Nov 21, 2007

Cummins actually does the Onan thing.

Look for a Cummins dealer they maybe able to get you a schematic.

Bill Barrett · Nov 21, 2007

Yahoo has a Case/Ingersoll group, you can find electrical info, parts, whatever you need.

Volfandt · Nov 21, 2007

Try here http://mytractorforum.com/forumdisplay.php?f=21

I don't know a whole lot about Onans, other than they are a very good air cooled engine that is unfortunately no longer manufactured, but I recall reading some troubleshooting tips. If you disconnect the two wires comeing from the stator (behind the flywheel) from the regulator you should read approx 20vac +/- 5 vac on them at pto speed. If you don't the stator may be bad or one or both of the wires may be shorted.
With the engine off and those two wires disconnected from the regulator, you should read some resistance across them (reading the stators windings) and NO continuity from either lead to frame ground. IF the stator reads a dead short between the leads and/or a dead short to ground, the stator or those wires may be bad and grounded to the engine frame.

Good luck

Mickey_Fx · Nov 21, 2007

If we're talking about an older flat twin, maybe I can help.

First, the electrics on an Onan used in RV's is a lot different and not much in common with tractor application. As has been mentioned, the alt is built-in under the flywheel. There is a soild state reg bolted to the cooling shroud. Looking at engine from back to front I seem to remember the reg is on the left bank (alum extrusion). The wiring has a plug. 2 A.C. wires from the alt and 1 wire D.C. out to the rest of the tractor. Think the A.C. wires are the outer 2. If you have a meter, with engine running you should see voltage when measured across the 2 A.C. wires. Don't recall the no load voltage but it will be more than 15V. If voltage looks OK, next check the D.C. voltage between the single wire and a ground point. Should be in the 14-14.5 volt range if battery is close to being fully charged. Believe all the reg does is shunt power to ground as needed to maintain proper voltage.

I had the original VR fail on my JD 318 with the Onan engine. Bought a new one from local JD dealer and all was well again.