Once snow hits i will put brand new spark plug in it.
When my father in law went to trade in his 2002 RMK 800 on his new sled, he tried to fire it up the day before trade in to make sure it was good to go for dealer and the oil tank had bypassed the check valves so bad over the summer that it hydro locked the engine and couldn't pull it over with the plugs in. We took turns pulling it over for a half hour clearing oil out the plug holes, then it would fire and oil foul the plugs instantly so we had them in and out 10 times or so cleaning the oil off before it cleaned up and ran. Smoked like a chimney for 20 min or so then cleared out a bit, ran it on the stand and thought it was cleaned out. Coming off the trailer the next day nose down, the sled puked oil out the exhaust all over the parking lot at the dealer cuz the belly of the pipe still had that much unburned oil in it. Father in law felt bad and explained the situation and the dealer was fine with it as he had seen it often before.
It's not uncommon for sleds to smoke a lot when cold, and they usually spit enough oil through the exhaust to speckle the floor of your garage or the snow when idling. Fill the fuel tank and oil tank all the way up before your first ride, then measure and fill both afterward to calculate your fuel to oil ratio. You should be in the 40:1 - 50:1 range. Run good full synthetic oil and have a blast.
For summer storage, unscrew the cap on the oil reservoir enough that the tank can breath air in and out with temperature swings. Tape your ignition key to the top of the cap so you don't forget to tighten it before the first ride the following winter. That should prevent the tank from pressuring up and pushing oil into the engine. However, the check valves can develop weak springs or get stuck open also, if your having oil loss into engine between rides with the cap screwed down tight, consider changing those out.
