2005-2007 Polaris Ranger 500 service manual, Page 109Get this manual
ENGINE Backfiring ETC or speed limiter system malfunction Fouled spark plug or incorrect plug or plug gap Carburetion faultylean condition Exhaust system air leaks Ignition system faulty: Spark plug cap crackedbroken Ignition coil faulty Ignition or kill switch circuit faulty Ignition timing incorrect Sheared flywheel key Poor connections in ignition system System wiring wet Valve sticking Air leaks in intake Lean condition Spark Plug Fouling Spark plug cap loose or faulty Choke cable adjustment or plungercable sticking Foreign material on choke plunger seat or plunger Incorrect spark plug heat range or gap Carburetor inlet needle and seat worn Jet needle andor needle jet worn or improperly adjusted Excessive carburetor vibration (loose or missing needle jet locating pins) Loose jets in carburetor or calibration incorrect for altitudetemperature Incorrect float level setting PVT system calibrated incorrectly or components worn or mis-adjusted Fuel quality poor (old) or octane too high Low compression Restricted exhaust Weak ignition (loose coil ground, faulty coil, stator, or ETC switch) ETC switch mis-adjusted Restricted air filter (main or pre-cleaner) or breather system Improperly assembled air intake system Restricted engine breather system Oil contaminated with fuel Restricted oil tank vent