Reply To: Howard 350 (Kohler engine) restart after years.

[wristpin]

America went over to unleaded fuel way before us, and all their small engine manufacturers were using hardened valve seats well ahead of us. They also offered the option positive valve rotation for certain constant speed applications such as generators and pumps. Your engine was made years before the introduction of ethanol adulterated fuel so go for the lowest E number available in your area.
Your possible time / heat related failure may not be ignition related. When it stops, push it straight into a shaded area, disconnect the plug lead, remove the plug, hold the lead 1/4” away from the head or head shield, and rotate the engine with the recoil. If you get a spark, look elsewhere – valve clearances perhaps.
There are a couple of eBay sellers for Meco units, but the Nova one seems to be favoured by Kohler users.
When considering replacing a conventional points and condenser system with an “electronic” trigger module, I like to have the engine running satisfactorily before the conversion. That way, one can be fairly sure that the coil etc are sound.
In the light of your issues with the flywheel nut, have you checked that the flywheel hasn’t shifted on the crank – sheared or partially sheared key?