2003 Polaris Scrambler 50-90 Sportsman 90 Predator 90 Service Manual, Page 53Get this manual
ENGINE that easily come out of placeUpon assembly, do not lubricate the one way rollers with heavy grease, as this will cause the one-way drive to malfunction5Inpect the washer and needle bearingReplace if any roughness or wear is presentWasher Restricted air filter (main or pre-cleaner) or breather system Improperly assembled air intake system Restricted air breather system Oil contaminated Engine Turns Over But Fails to Start No fuel Dirt in fuel line or filter Fuel will not pass through fuel valve Tank vent plugged or pinched Carb starter circuit plugged Engine flooded Low compression (high cylinder leakage) No spark (Spark plug fouled) ignition component failure Safety switches malfunctioning (Ignition, Kill, Braketostart) Electrical malfunction
Needle Bearing 6To reinstall the starter drive oneway, reverse the procedures
TROUBLESHOOTING
Spark Plug Fouling Spark plug cap loose or faulty Choke plunger sticking or inoperative 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 clips) Loose jets in carburetor or calibration incorrect for altitudetemperature Incorrect float level setting CVT system calibrated incorrectly components worn or mis-adjusted Fuel quality poor (old) or octane too high Low compression Plugged exhaust Weak ignition (loose coil ground, faulty coil, stator, or ETC switch) ETC switch mis-adjusted