I have the same tractor, have had all the starting problems. Something to seriously check (or replace) is the positive battery terminal. I was roading about ten miles to brushhog our vacant lot. Left the house with a fully charged battery (tender showed green). Drove about 8 miles, stopped to take a leak and forgot to put in neutral and it died. Wouldn't restart. Called my wife and we jump started it without a problem. I know the battery was good and the switch was recently replaced. Didnt even want to think about the alternator. Anyway, read on this forum about the positive battery terminal being corroded inside. Last weekend I sawed it off, peeled back the rubber coating on the wire and sure enough corrosion! Last weekend I connected a generic terminal and it fired without issue. We'll see if this fix "stands the test of time".