Snowmobile Repair: 79 blizzard, ski doo, spark plugs

Question
Hi:
I have a 79 blizzard 5500 that won't stop blowing plugs. Depending on the carb adjustment it could be either plug that blows. Do you have any ideas?
Rob

Answer
Hello Rob,
 It sounds like you have a problem that a lot of pre-1982 Ski-Doo's have, going through spark plugs a soon as you install them. I have had the same problem with my Ski-Doo 440 and have had alot of success by installing a set of spark plugs that is one range hotter then the originals, which with your sled would be a NGK BR7ES. Also, I would recomend using Castrol High-performace snowmobile oil at a ratio of 24:1. If none of this information helps or you don't think this is the problem I would recomend rebuiling the carburetor. Let me know if I can answer any other questions you might have.Good luck with the sled! Mr.W