Kohler K181 Rebuild/Ignition Questions

Okay so IDK why but I'm suddenly inspired to work on this Kohler.  The 2 that are partially parted out seem in good shape, pulled the head on one and the crosshatching is really good, valves seat great, no carbon build up, great compression, so I figured why not try.

Only thing is, the 2 that have rods are both off of a round fender JD, which had starter generators which are, of course, long gone.  The one that threw the rod has a ring gear on its flywheel, and the blocks on the starter generator ones have the bolts to bolt the starter to it.  So I figured I'd swap flywheels.

Heres where I'm super confused.





The stator on the ring gear flywheel (not present on the other flywheels) is magnetic.  Not only that, the spark plug wire comes right off of it and runs to the plug.  Did some research and apparently my model JD had a magneto ignition.



Thread link: https://www.wfmachines.com/forums/showthread.php/16985-1968-JD-110-8hp-K181S-Kohler-Ignition

I thought that these engines required a battery to run?  Also, people in that thread are still talking about points and condensers and stuff, and why does the Kohler with the thrown rod have points if it's a coil ignition?  What's different between this and my Predator/B&S ignition?  Who's on first?

Any help is appreciated.

The coil under the flywheel is most likely only a spark generator and has nothing to do with timing. That's how a couple of my old Kohlers are, but without the stator. So basically the coil and condenser work to make spark and the breaker points control the timing. The engine that came out of your tractor is 12v ignition which is the same principle, but the coil in that system converts the low power from the battery into high power to create spark. Just like vehicles and tractors all used at one point.

Most people seem to think breaker points ignition is useless, but the truth is it actually creates a stronger spark than a solid state ignition setup. The only drawback being that breaker points ignition isn't quite as consistent.

Why does it need a spark generator when the coil and condenser make spark? And why is it a 12v ignition if it make its own spark?

Gonna look into points/wiring and stuff. Is everything from the points there? I pieced this together off all 3 engines.

Sorry, I was saying the coil under the flywheel is a "spark generator" of sorts. There is no internal breaker in those old coils like there is in the mag of a newer solid state engine, such as your Predator. In this older setup the points act as the breaker to allow the spark to happen at the right time. Same idea sort of except it's all external. All the old cast iron Briggs engines like the model 19D, 23D, 24, etc, use a setup quite similar to this.

Also 12v ignition makes its own spark from very small amounts of power taken from the battery. The coil in that setup is there to convert that into the very high energy needed to make spark. Same idea as the under the flywheel coil setup but, instead of magnets, the battery provides the energy.

The pic up above is a mag coil with a stator, it provides ignition spark and also power for the electrical from magnets on the flywheel. The points and condenser are the other parts of the magneto. As for the charging system on the same stator with the mag, the 2 should be wired separate from each other and work independently. You should have atleast 3 wires plus the spark plug wire on the stator.

For ignitions to be using external power, the coil is by itself with wires going to it. A magneto is self powered by a magnet that spins in timing with the engine.

A condenser and points are also used for powered ignitions with a coil by itself too. These 2 parts are used to trigger the power to a coil whether the coil is for a mag or powered ignition. The giveaway for a mag setup is the coil is energized by a magnet at a timed moment by engine rotation. The magnet for the mag will probably be bigger then the magnets for the charging, on the same flywheel, I think.

Ok, thanks for the clarification!

Clean up that engine! Any oil or debris on the points will cause issues. So ya gonna use it on nelle belle?