To tune a snowmobile carburetor, adjust the low and high speed needles of the unit by rotating them the required number of times in the appropriate directions. Run the vehicle's engine for a brief time period, and then switch it off.
To adjust a snowmobile carburetor's low speed needle, first warm up the vehicle's engine. To do this, run the snowmobile for approximately five minutes. Then, undo the clips on the engine compartment located towards the vehicle's front side, and take out the engine's access panel.
Switch off the engine, and identify the low speed needle present on the carburetor's left side. Now, position a screwdriver with a flat head in the needle's groove, and rotate the needle by one-half a turn clockwise. Then, rotate the needle one-and-a-half times counter-clockwise, run the engine for about five minutes, and switch it off.
Repeat the process to adjust the carburetor's high speed needle located on top of the unit. After completing the required number of rotations, run the engine on an even surface and at a high speed for around five minutes.
Switch off the engine, and rotate the high speed needle one-eighth of a turn clockwise. Switch on the engine again. If the engine does not perform as required, repeat the high speed needle adjustment process. End the same by rotating the high speed needle 1/8 of a turn counter-clockwise.