My brother's sled was running on one cyclinder. He tried new plugs and nothing. He was getting spark at both cylinders. He thought maybe a carb or choke problem to the one side. Then thought maybe weak spark at the bad side. So he did something interesting. There was an old 76 Lynx with about a 300 free air motor in it. He knew it ran. He took the big nasty old ignition coil out of it and replaced his smaller coil. Started her up and she ran strong. Must have put at least 100 miles on since then. I was a bit suprised, not that it started, but that it kept running like it was the proper coil for the sled. So anyone know if that is ok, or do you think it will cause damage to someting else on the sled? He said he was going to buy a coil for it, not sure if he did yet. That was on Christmas night so he had to improvise if he wanted to ride. Just that it was cool that it actually worked.