Snowmobile Repair: fuel mixture, vintage sled, fuel mixture

Question
I inhereted a 1971 arctic cat puma 399 with the jlo engine.. what is the fuel mixture for this machine. I am running 35 to 1 ... I tried 20 to one but it was just loading up.

Answer
Hello Anthony,

  Congratulations on inheriting an vintage Cat! The original mixture for the sled is 20:1 . Nearly all vintage sleds don't really like this mixture when they get old. I have gone as far as 40:1 on my vintage sled, with no problems. I would not recommend a ratio of 40:1 on a JLO engine. Ideally, 32:1 would be good for the sled. Also, using Amsoil Synthetic helps cut down on the loading up. Be sure to use the correct plugs, they are Champion N3. The horse power on those sleds at full RPM is 28, not bad for a '71. If you have any other questions, let me know! Hope this helps. Good luck with the sled! --Arcticatman