Kohler ignition coil keeps failing

Have a John Deere mower with 17hp Kohler engine, have replaced the ignition coil now 5 times, sometimes last a year, had one fail on the second start up, have checked the kill wire and switch.
does anyone have any idea what would cause the coil to keep failing?
Thanks!

Intermittent short that is causing 12v to go to the coil and burn it out. Most likely cause is a faulty key switch but could be safety switches, or just a bare wire someplace in the harness.

My best guess would be a bad voltage regulator, bad ground connection on the regulator or a bad ballast resistor. An ungrounded regulator would allow the battery voltage to shoot up and smoke coils.
Post the model number or picture of the wiring if you have it.

What is it said:

My best guess would be a bad voltage regulator, bad ground connection on the regulator or a bad ballast resistor. An ungrounded regulator would allow the battery voltage to shoot up and smoke coils.
Post the model number or picture of the wiring if you have it.

Click to expand...

Would you like to illustrate how battery voltage would affect a self energising magneto ?
I am at a loss to see any connection between the two whatsoever .

You're absolutely correct! -- If it's a magneto. The OP said he was burning up 'coils'. depending on the age and model it may well be a battery powered coil. This is why I said 'best guess' and asked for a model#.

If this is the smart spark ignition system, or the other battery powers ignition system they are susceptible to voltage spikes like from bad voltage regulators, faulty batteries,jump starting the engine and then disconnecting the jumper leads on a mower with a bad battery or even turning off the electric clutch can spike the system and cook the ignition system.

ok to claify, this motor uses a magneto coil, so no connection to the 12 electrical system of the mower. Thanks for all the replies!
Morguns1Cam

IT is a problem when we do not get the full details / description of the machine.
So in this case the original post applies

To explain inside the coil is an embedded micro chip that turns the coil on & off.
It does this by measuring the tiny induced current in the coils as the magnets are passing .
These chips are very sensitive to reverse volltage coming down the ground ( kill ) wire.
So by far the most common reason why several will fail is power coming down that wire.

Just hooking up the battery backwards can do it , even some cheap multimeters can fry the chip.

If there is no pattern to the failures then you most likely have a pair of pinched wires or some bare wires at a safety switch, or an internal short in one of the safety switches.

Finding it will not be easy but if you care to post your mower model numbers we can at least look up your mower & make some better suggestions.
A full set of switches will set you back around $ 100 if you want to take the "replace everything" approach and as it is a JD you will be able to by a complete wiring harness but I have never done this so no idea of the price of one.
You can install a kill relay into the magneto kill wire which if nothing else will prevent you blowing the magneto coils which can get very expensive very quickly.
However this will not be a fix, just a band aid .