2006-2014 Honda FourTrax ATV TRX250 EX TRX250X Service Manual, Page 357Get this manual
TROUBLESHOOTING
POOR PERFORMANCE AT LOW AND IDLE SPEED
1Carburetor Pilot Screw Adjustment Inspection Check carburetor pilot screw adjustmentIs the pilot screw properly adjusted? NO YESAdjust the carburetor pilot screw (page 6-15)GO TO STEP 2
2Carburetor Insulator Inspection Check for leaking carburetor insulatorIs the carburetor insulator leaking? YESFaulty insulator O-ring Damaged insulator Loose carburetor mounting nutsGO TO STEP 3
3Spark Test Perform spark test, inspecting for weak or intermittent sparkIs the spark quality good? NOFaulty spark plug Fouled spark plug Loose or disconnected ignition system wires Broken or shorted spark plug wire Faulty ignition coil Faulty CKP sensor Faulty exciter coil Faulty engine stop switch Faulty ignition switch Faulty ignition control module (ICM)