I have a 2003 Mountain Cat 900 1M. I just bought it with 700 miles on it. I took it for a 40 mile ride, then an 80 miles ride and it ran great. After that, I took it out and about 5 mins into the ride it died. Just instantly shut off dead. I tried pulling the rope and to my surprise, it went! It did this one more time and then ran good for the rest of the day.
The next time out, it died 5 mins into the ride again. This time, the recoil was locked up like the engine was seized. I waited a while and the rope pulled out fine like nothing was wrong. It died again 1 min later. I waited a bit started it, and it ran good for the rest of the day.
The last time I took it out, it did this again. Died 5 mins into ride. Engine seized up. Waited, it released and fired up on one cylinder only. One spark plug is wet the other is dry with some black carbon on it. Towed it home.
What could be wrong? I have ruled out ice as it can’t be froze up all those times, I do use isopropyl. Not spark plug either. HELP!
Also, as a side note, it only revs to 7250 to 7500 RPM, is that normal or should it hit 8000 or 8500?

I had a similar problem. A new ECU cured it.