2002 Polaris Universal Snowmobile Owners Manual - Page 114

MAINTENANCE General Maintenance Under Hood Air Intake System The under-hood air intake system on Indy 340's should normally be left open. However, for maximum performance in temperatures above 35° F (2° C) and in loose snow, the door should be closed and latched (A). Pull the strap out and up to latch the door and reverse the procedure to open it. A Spark Plug Selection It's very important to use the correct spark plug for your machine. A spark plug with a heat range too high will cause engine damage. A spark plug with a heat range too low will cause excessive fouling and engine malfunctioning. In selecting a spark plug heat range for production, a manufacturer assumes that the engine will be operated under extreme heavy duty conditions and selects a spark plug that will protect the engine from internal damage if the purchaser actually does operate the engine in this manner. This selection could cause the customer who normally operates the engine under medium or light duty to have spark plug failure. Refer to your Owner's Manual Supplement for the specific spark plug to be used in your machine. CAUTION A plug with a heat range too high will always cause engine damage if the engine is operated in conditions more severe than that for which the spark plug was intended. 112