1990-1998 Arctic Cat Snowmobiles Repair Manual, Page 139Get this manual
ADJUSTMENTS FOR SPECIAL USE 2Unscrew and remove the carburetor top cap (Figure 5) and pull the throttle valve assembly (Figure 6) from the carburetor3Remove the jet needle (Figure 7, typical) from the throttle valvescrews or any other small pieces when removing the jet needle
NOTE Some models have washer installed on the jet needleDo not lose the washer,
4Note the position of the clip (Figure 4) before removing itRemove the clip and reposition it on the jet needleMake sure the clip seats in the needle groove completely5Reverse the procedure to assembleMake sure the seal (Figure 8) in the cap is positioned correctly before installing the cap
High-speed tuning
The main jet controls the mixture from 34 to full open throttle (Figure 1)The main jet also has some effect at lesser throttle openingsEach main jet is stamped with numberLarger numbers provide richer mixture, smaller numbers leaner mixtureRefer to Table for the initial size of the main jetWhen operating the snowmobile in relatively warm weather or at higher altitude, smaller main jet should be usedWhen operating the snowmobile in excessively cold weather conditions and lower altitudes, install larger main jetCAUTION The information given in Table for determining main jet sizes should be used as guideline onlyVariables may exist with each individual machine and the specific operating conditionSpark plug condition is the most reliable source of information regarding carburetor jetting, but the ability to correctly read the spark plugs is gained by experienceIncorrect changes can seriously damage the engine, therefore it is suggested that an Arctic Cat dealer in the area where you will be operating be consulted regarding approximate jetting changesWhen in doubt, always select jets on the rich side