I'll go out on a limb here and make a suggestion and you can do whatever you want with it. If you are somewhat handy, and it sounds like you are, why not take one of the older B&S engines off your older riders and fit it to the new chassis & deck? If the bolt holes, exhaust and whatever else lines up, you can rewire the starting, charging & ignition system so you can at least cut your grass with minimal expense. If Kohler does work with you, you will have to take the engine in anyway. Worth a try??? On the other hand I have had to borrow a mower from a friend to get by.