Well... this is just my opinion... cover the basics.. siphon out all the old gas... easy way... just buy some vinyl hose.. buy a long section and so you can watch the fuel and avoid drinking it. The hose is going to want to coil up.. take a metal coat hanger, cut it, straighten it out and insert it into the vinyl hose.. now the hose will stay straight and at the bottom of the tank.. replace the fuel with 87 octane.. these sled are fine with it.. and retest on a cold night..
as the hose.. remove the coat hander.. coil it up, coil up the vinyl hose and place them in the back of the sled.... now you are set up.. incase you need a siphon hose in the woods..
also.. cycle the key twice.. before trying to start it.. if for some reason, if your fuel pressure is bleeding off.. you will have extended cranks on a cold start without an initial key cycle..
At 10k (Kilometers) aka 6000.00 miles you shouldn't need to check the valve shims... but.. if the sled has spent most of its life with the throttle wide open.. wouldn't hurt to check your valve clearance. Tight valves = hard starts