Snowmobile Repair: Sleds not running right..., carburetor repair kit, ngk plugs

Question
hi, i have a 87 Yamaha XLV 540, it's air cooled and isn't premix.  Ever since last season when riding it would loose power and then kick back in and sometimes back fire...now the sled starts and it will only rev to 2500rpm and the sled makes a pinging noise when it's given as much throttle as possible (w. the 2500rpm max)  the clutch engages when the gas is given but the sled doesn't go beyond that rpm and the track won't engage.  So i took the carburator off and cleaned it, drained the gas and the spark plugs are new but wet with gas... i don't know what else to do..

Answer
Hello Ethan,

  Sounds like you have two problems. One, would be that you probably need a new coil. The other would be installing a carburetor repair kit. You are getting way to much fuel and it is flooding the sled out. I wouldn't use NGK plugs, if that is what you are using, either. Champion Powersport spark plugs are ideal, or Autolite. Also, make sure that your float height is properly set, that can cause this problem. The inlet needle in the carb is probably causing most of the problem. If you soak it in carb cleaner for a few hours, and then carefully clean it, and it's seat, that will help. Buying a carb kit would be more ideal. You can go to www.denniskirk.com or www.mfgsupply.com for excellent prices on a carb kit and coil. Hope this helps, let me know if you need any help at all. Good luck with the Yamaha! --Arcticatman