Any new 2015 skidoo mountain sleds seem to be fouling plugs. Ive ran into this problem with multiple of my friends and family and the sleds do not want to start. Today my sled quite on me while riding and i couldn't start it. I found a temp fix to get your sled started. Remove your tether and plug it back in one or two times and also click your kill switch in and out a few times. I have no idea why it works exactly but it worked everytime today and i rode the rest of the day fine. FYI theres a recall for this problem..