2001 rmk 800 cut out at high elevation

Is this a new to you sled? If not, did it run good last season at same altitude? If it idles good, and runs well at full throttle, it would normally mean you need to make a needle clip adjustment for the mid range.

SD

You are not really giving enough info, for anyone to diagnose your problem. The pilot jets control idle & low speed. The needles (clip setting) controls midrange 1/4 to 3/4 of throttle. The main jets control 3/4 to wot. All three have some effect on each other.

To answer your question, you have to remove the carb caps on top, and remove the needles. There is an adjusting clip on them, for richer or leaner. Raising the clip is leaner, lowering the clip is richer.

SD