2008 Polaris ATV Predator 50, Sportsman Outlaw 90 Service Manual, Page 86Get this manual
ENGINETRANSMISSION TROUBLESHOOTING
Spark Plug Fouling
Spark plug cap loose or faulty Choke cable adjustment, cable or shaft sticking Incorrect spark plug heat range or gap Carburetor inlet needle and seat worn Jet needle andor needle jet worn or improperly adjusted Loose jets in carburetor or calibration incorrect for altitudetemperature Incorrect float level setting CVT system calibrated incorrectly or components worn or mis-adjusted Fuel quality poor (old) 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 crankcase vent (engine breather)