When you are out on your snowmobile riding and you notice that something is preventing the engine from performing at its optimal level, you prepare yourself for the worst case scenario. Although there are a lot of potential causes of decreased power and performance on your snowmobile that will warrant some heavy-duty overhaul, often times, you can get your snowmobile back to peak performance by tuning the carburetor. Instead of cutting the outing short and wondering if your snowmobile might leave you stranded, you can get under the hood yourself and make a few simple adjustments to the carburetor and return to full speed.
Adjust the low speed-needle
Ride the snowmobile for about five minutes to warm the engine up.
Remove the access panel to the engine by releasing the clips on the outside of the engine compartment on the front end of the machine.
Shut off engine, and find the low speed needle. The low speed needle is located on the left side of the carburetor as you look at it from the front of the machine with the access panel open.
Turn the low speed needle one-half rotation in the clockwise direction, by inserting a flat-head screwdriver into the groove on the top-side of the needle.
Turn the low speed needle 1.5 rotations in the counter-clockwise direction, and start the engine again. Allow the engine to run for a 5 minutes before turning it off.
Adjust the high speed needle
Shut off engine and find the high-speed needle on the carburetor. The high-speed needle is located on the top of the carburetor.
Turn the high speed needle 1/2 rotation in the clockwise direction by inserting a flathead screwdriver in the groove on the top-side of the needle.
Turn the needle 1.5 rotations in the counterclockwise direction with a flat-head screwdriver.
Start the engine and ride the snowmobile at a high speed on level ground for five minutes and stop.
Turn the high speed needle 1/8 of a rotation in the clock-wise direction and test drive the snowmobile on level ground again. Repeat this process until you achieve the desired performance level and then turn the high speed needle 1/8 rotation in the counter-clockwise direction to finalize the tuning process.