2004 Polaris Pro X Snowmobiles Owners Manual - Page 63

Carburetion OPERATION Proper carburetor adjustment is critical. A lean mixture (too much air, too little fuel) may result in piston burning, bearing failure, or complete engine failure. A rich mixture (too much fuel, too little air) may foul plugs and cause generally poor engine performance. A lean mixture may be caused by things like fuel line restrictions, foreign matter in the carburetor or clogged fuel filters. A rich mixture may be caused by snow build-up on the pre-filter in the air intake system. Either condition may be caused by improper carburetor adjustment. WARNING Improper carburetor adjustments may result in operator safety hazards as well as serious engine damage. Always have your Polaris dealer perform any carburetor adjustments. Jetting Guidelines Changes in altitude and temperature affect air density, which is the amount of oxygen available for combustion. In low elevations and cold temperatures, the air has more oxygen. In higher elevations and higher temperatures, the air is less dense. Carburetors on most Polaris models are calibrated for an altitude of 0-2000 ft (0-600 meters) and ambient temperatures between -10 to +10 F (-23 to -12 C). All carburetors must be re-calibrated if operated outside this production temperature and/or altitude range. The main jet installed in production is not correct for all altitudes and/or temperatures. CAUTION A main jet that's too small will cause a lean operating condition and may cause serious engine damage. Jet the carburetors carefully for elevation and temperature according to the jetting charts in your Owner's Manual Supplement. NOTE: It's the owner's responsibility to ensure that the correct jets are installed in the machine for a geographical area. Be very careful when jetting down in warm weather. As the weather turns colder it will be necessary to re-jet upward to prevent engine damage. When selecting the proper main jet always use the lowest elevation and temperature that is likely to be encountered. 61