Newby with JD LT133 Question

My neighbor had trouble starting his John Deere LT133, claims he hooked up battery wrong and "fried something". He wouund up buying a new lawn tractor and giving me the LT133 as he knows I like to work on this stuff. As I started diagnosing the problem, I realized after pulling the flywheel that there was a mouse under stator causing, from what I an gather, the stator to fry and melt the plastic protective barrier between copper winding and the round metal part of stator. Now my task is to find a stator. Engine is a CV13S, spec is 21525 which I understand now is important to know. The stator that was on the tracto has two wires, green and black that lead to a harness clip holding four wires. The wires on that clip include the two wires from the stator, the white wire from the coil (i think that's what it is) and a yellow wire. The problem is the yellow wire coming from the harness clip was soldered into the black wire coming from the stator? After much research I found that the spec 21525 engine has a stator with "brake". The stator for this has three wires, yellow, green and black, precisely what comes from the clip.
My questions are:
I've read that these engines do not have a regulator rectifier, but he do have a diode. Where is the diode?
Did I buy the correct stator? Part number is 12-085-08S.
If I hook up the new stator, will it casue engine surge in current? I say this because I've read that the stator originally was a 3amp but they changed them to 15 amp.
I need to ask my neighbor if he ever had work done to the tractor because I would doubt that it would come from the factory with a soldered wire wrapped in electrical tape.
Any help is greatly appreciated.....
Thanks,
Eric