I have a 2000 LT160 that my middle son used to ride. He outgrew it a year and a half ago, so I put it away in my shed till my youngest grew into it. It ran perfect when I put it away. I pulled the battery and parked it. This week I decided my youngest was ready for it, so I pulled it out and put a good battery in it, drained the gas and added new, and gave it a new spark plug. When I turn on the key and press the start button, it fires right up but dies out as soon as I release the start button. If I keep pressing the start button after it fires up, it continues to run until I release the start button. My first instinct is something electrical is wrong. Anyone have any ideas?