Ok, Its a 2000 AC 300, problem #1started a couple of years back.  It got an unconsistant miss to it, which would cause it to stall if at idle.  I have gone over the valves and carb many times with no change at all.   I even changed the CDI (with a used one) to see if that made a diff, and it did not.  This problem let to problem #2, I was doing alot of snow plowing when it started acting up, and the constant stalling and restarting caused something to go.  which would more likely go first, the gear on the starter, or the gear it turns?  I would like to pull the quad out of retirement, but again dont know where to start to find the problems.  Thanks in advance for any help!!!!  

sorry,  I dont know how this got posted twice, computer must have burped or somthing.