have you had the engine shroud sheet metal off to clean the fins well ?

Maybe....... it's your choice of coil. If you are running an automotive coil instead of an actual Kohler OEM coil, then there's your problem. Kohler coils have an internal resistor that allows them to take the full 12 volts from your electrical system. Automobile coils are actually 8 volt coils that rely on an EXTERNAL resistor to take up the other 4 volts of power.

On autos that are expected to crank over in sub-zero weather, there is a mechanism in the electrical system that sends a full 12 volts to the coil only while the starter motor is spinning. When the engine starts up and the starter is disengaged, the electrical system provides power once more through the external ballast resistor and the coil only sees 8 volts from that point on.

If you are running an 8 volt coil on the full 12 volts, then you've increased the supply voltage by a full 50 percent and that's what's causing the coil to overheat and fail. Go to your local NAPA dealer. You have 3 choices of coils from him. They sell all kinds of Kohler parts including the coil. They also have Bosch coils. Bosch makes two models. The black coil is part number 00015 and is a 12 kv coil. The more expensive Bosch Blue coil is part number 00012 is the 18 kv coil that is commonly used by people who build Kohlers for competition purposes such as "pulling".

Does this help? If so, then please report back here so others may learn from this while searching the archives.

All you have to do is ask for an internal resistor type coil at the local parts store. Most aftermarket coils have internal or external resistor stamped on the outside of the coil. The OEM Kohler coils seem to always not have the marking on them.