I just picked up a 87 trailboss 250 for the girlfriend last week. Checked everything out, drained, flushed, and filled the gas tank, boiled out, cleaned, and reassembled carb. It ran awesome cold (85 degree air temp), would go around the neighborhood just fine, start easy cold with no choke, etc. No problems going around the block.

We took it camping last weekend and the problems began. About 5-10 miles down the road when it would really warm up, it would get very boggy, or act like the throttle was stuck wide open(one or the other). If it would stall out, it would restart 3-5 pulls later holding the throttle open slightly but not want to idle on its own. She would walk away from it and let it cool off, come back 45-60 min later and it would fire right up and run amazing for another 5-10 miles, ending with the same symptoms.

I pulled the carb back apart to verify main jet, pilot jet, all needles, etc were clean and Nothing was blocked.

Where should I start with this? I don’t want to sink $1000 into a $700 machine if I can help it, just doing a little more homework before I tear it down. My dad thinks either the oil injection is screwing up causing problems or the magneto is on its way out and giving weak spark when warm. The (auto) mechanic at my work thinks the rings are weak and the compression is going away when it fully warms up.

My only other experience with 2smokes are my two fan cooled 1988 Polaris 488 fan snowmobiles and Ive never run into problems like this.

Thanks in advance!