Charles,
That CH22S used an analog "Smart Spark" ignition unit and modules. The typical failure would be a weakening module, or coil as some call them. Your dealer has a special test using an 18kv tester on the plug wires for these engines. It'll find the weak coil in a few minutes.
He can also bench test the Smart Spark box itself, that's the rectangular black box mounted on the flywheel cover, RH side. However based upon your symptoms, it seems to indicate the ignition module/coil is the problem.
How do you get to it? That's the fun part, they mount next to the flywheel so that cover must be removed, in a 2284 you'd likely need to move the engine forward to access it.
I had lots of problems with my 2284 ignition, to be honest with you. A kind soul sent me 2 new modules and a flywheel to eliminate the Smart Spark system (which is a spark retard device for variable timing)on mine, it was night and day's difference! The 18 20 and 23 HP Commands are fixed timing engines, which eliminates the Smart Spark problems.
You want an 18 degree flywheel and (2) 18/20 HP modules. Maybe give the Engine Service guys at Kohler a call????? If they will help you with parts that'd be great!