Today I was actually allowed by the school to ride my sled in. I got halfway there and my plugs fouled out. I put in some fresh ones, and tryed to start it...Each pull I only got little "stutters", or it idled for 5-10 seconds at really low RPMs. It was about 2 degrees out. I pulled it over about 15 times then to my luck the recoil rope broke. What was the problem with the starting(before the rope broke)? This is the first time it hasn't started right up after changing plugs.