I think you are saying that you see the trans pulley quit turning when you release the bail- but you still can't pull back the unit? For each wheel there is a drive clutch that you can carefully disassemble, lay everything out as it goes back together and clean/ lube them. Then your wheels should release.

By all means save this Mower with the Kawasaki engine! I've just saved ours, and when I got to looking into engine wearout, I was shocked to see that the valve adjustments held steady for 15 years, and are within .0005 of what the spec is! That is unbelievable, even cars don't hold tolerances that well as they undergo a lot of wear and tear. Your problem is probably the same exact same one that I had. It throws you for a loop for sure. MOST LIKELY it is your carburetor MAIN JET, that you need to actually unscrew and clean with nylon Fishing Line. Yes! My Jet actually looked great, with my eyesight, it had a very round opening and didn't look like any junk was blocking it. BUT ... there was uniform build-up of gasoline residues, that I was able to rough-out, but using fishing line and just running it through the jet maybe 10 times, and when I saw the opening getting larger, I knew I was onto something! The Fishing Line won't damage the soft brass jet, so don't worry about enlarging the opening too much. But once you get this back in, and your Carb back on, you will be amazed! As you throttle-up and then Engage the Blade Clutch, the Engine will pull strongly and NOT Stall-Out !!! Oh - There is NO replacement or rebuilt carburetor available, so treat it well, you can probably re-use the same gaskets, and maybe a little bit of gasket sealer -Automotive type is fine. Good Luck !

This maybe too late for you, but it may help others who do not want to pay $700.00 for a new engine from John Deere. I just installed an FJ180V-CS11-R on a 14SB frame, which I believe to be the same frame as the early JX75 that you have. In any event, the original engine on the 14SB was an FC150V-FS00. The new new engine fit with out any modifications, and the blade guide, pulley and BBC fit perfectly. The only thing I had to do was tap the mounting holes and shorten one mounting bolt to 1-inch. One note - the throttle control works backwards, in that the choke is at the off setting (throttle back) and off is at the choke setting (throttle forward). If anyone has the trick to change this let me know. Check out the Small Engine Warehouse online or E-bay for the engine (about $200.00 + shipping).

Re the transmission in the 14SE/SB I just got given one for free, and was not too impressed but then I noticed the Kawasaki engine (wow!) and decided that it was worth fixing. My 14 SE had a completely seized up transmission and 3 broken cables. Only the blade clutch cable was working...but it's really the only one you need. The throttle mech still works fine with no cables. You can just remove and throw away the speed control and throttle control, cut off the belt drive, remove and discard the transmission and still have a very nice, MUCH easier to push commercial mower when you are done. About an hour's work in all. Pull off the electric starter too while you are at it and then you have a nice lightweight, uncomplicated commercial mower that has far fewer parts to maintain.