1. GENERAL INFORMATION ATV 300/250 NO SPARK AT SPARK PLUG Inspection/Adjustment Symptom Probable Cause Replace with a new spark plug and inspect again Weak or no spark Good spark Faulty spark plug Check spark plug cap and high-tension wire for looseness Not loose Loose Loose spark plug cap Check ignition unit coupler for looseness Good Good Poorly connected coupler Measure resistance between terminals of ignition unit coupler Normal Abnormal Check related parts Faulty ignition switch Weak battery Normal Abnormal Faulty pulser coil Faulty ignition coil Faulty charging system Broken wire harness Poorly connected coupler Check ignition unit with a ignition unit tester Faulty ignition unit Normal Abnormal Faulty change gear control unit Check ignition coil with a ignition unit tester Abnormal Faulty ignition coil 1-26