Kitty Cat Snowmobiles

Hi,
I have been using this forum to get my sons 78 kitty cat running so thanks for all the great info.

Here is my situation-- cat will not start-turns over great- good compression, good spark, new rings, new seals, new gaskets- suction at intake- carb has been rebuilt with 2.0 needle and reset pilot screw to 1.5 turns from in-gas flow from the tank is good-float is adjusted-drove it for about 20 minutes one evening - plenty of power and started in 2 pulls- started fine 3 days later and rode for about 30 minutes- sat for 3 more days then started after 3 pulls- plenty of power- no bogging-had been running for about 20 minutes and it died out while driving it- now it does not start and I have double checked all the above. Dont want to seem stupid here- I have good mechanical background with cars dont know much about sleds- I had a sled guy help me rebuild the motor and rering etc. Any help would be much appreciated. Thanks.

Maybe the points loosened and closed up???[/b]

Thanks for the reply THX.
I went to double check some things and while pulling to try to start it locked up the motor- took it apart and found one of the c-clips from piston had lodged into the side of the piston and the cylinder-ouch! Anyhow, thanks again for the advice- it motivated me to go back out and work on it some more.