It was idling with the choke open about 3/4. I got to doing something and about the time my hands were full, it started to rev up, held it for half a minute, settled back down and quit. Now it won't start. My first tho't was it ran out of gas so switched to reserve - nope. Added new gas, nope. Added a little gas line anti-freeze and waited. Nope. Any ideas before I have to call my mechanic? 2003 Polaris 500 Sportsman.