The engine just quit. Has gas, oil and battery is good. Starter engages and torques the engine, but the engine does not even get a partial stroke. It torques hard and starter is trying to turn it over but the engine will not rotate. If I turn the crankshaft by hand it goes about a 32nd of an inch and stops. This is on a John Deere z-track with a commercial 5 foot wide mowing deck, so not something I can load on a trailer and take to the dealer. I replaced the engine 6 years ago and can do it again if need be, but would like some trouble shooting advice before going to that extreme as the engine was operating fine up to the point where it just stopped - didn't make any unusual noise, no smoke, just stopped and now won't turn over. Tried calling Kohler but they don't have over the phone trouble shooting assistance.