Sounds like a coil, one of the guys I ride with his sled was running good and shut off and then went to start only ran on one cylinder, took a coil off a spare sled and finished riding the weekend.
Check the chain while you change the oil, grease the bushings that the ski bolt goes through. Clean the clutch faces. Check belt height in secondary. Track tension and alignment just a few to start.
Just came back from Climina. We drove to the Snow line at 13km mark but was melting fast due to the pouring rain. Never unload sleds due to the heavy rain fall. It was 5-6 degrees above freezing at 1500 meters of elevation. Unless the rain changes to snow it is a waste of time to come up right now.