Allen S, Jimmy L,
You can probably get pretty close by going by the ballance holes, I just looked at another flywheel and the are two balance holes on it, one by each mark. I also noticed something else about the second flywheel, it has a thicker base and shorter blades. The overall height, diameter, and crankshaft hole is the same, but the thicker (second) wheel is 3 lbs heaver that the one I took pictures of, so there may be a difference between the 10 and 12 hp wheels although the Cub Cadet parts manuals (TC-113) show the same Kohler part number for the 10 and 12hp wheel (KH 47-755-02), there may have been a design change made by Kohler at some point. I'll try to do some research sometime when I don't have anything else to do. Some of the earlier Parts manuals such as the TC-103 for the 70/100 list IH numbers for the flywheel and other engine parts. K161, K241, and K301 are the only engines I normally play with, so if Kohler didn't make a change at some point, I'm not sure where the wheel I took pictures came from unless it had been changed on an engine prior to me getting it. The Kohler parts manual shows several different flywheels for the 10 and 12 hp engines, depending on the what the spec number of the engine is.