Bucksaw

try taking the muffler off and check where the the muffler clamps over a rubber gromet to the frame i bet you find cracks at the clamp on the muffler

Checked...no cracks. Thanks anyway.

The plug was black-ish. Running a bit rich, but I removed the oiler and pre mixed 40-1, so it should be OK. Let it idle for a while and the exhaust was cool to the touch. I think what ever caused the heat has been resolved by the previous owner(s).

Found this old post
"had similar problem with my 06 freestyle 300 ,carb rubber boot had spidercracks and wasnt running to good at idle,was ckoking it a bit to get going when it started to act up and got extra gas in muffler,lol of course this was way back trying to get back home,it got cherry red and caught fire,got out before to much damaged happened" So, running with the choke on may have been the issue????

No electric start on my sled and the track tension is good. What ever caused the situation may have been resolved by the previous owner....I hope.

Ravinerat: I did see that thread.