4. FUEL SYSTEM QUANNON 125 A.C.V. AIR CUT-OFF VALVE (A.C.V.) REMOVAL Remove the throttle stay plate set. Disconnect the tubes that go to the air cut-off valve. Remove the two attaching screws. Remove the air cut-off valve. Screws Spring DISASSEMBLY Remove the two attaching screws to remove the air cut-off valve cover. Remove the spring and diaphragm. INSPECTION Inspect the check valve for proper operation. Inspect the air cut-off valve diaphragm and O-ring for deterioration or damage. Replace with new ones if necessary. Clean each air passage with compressed air. Diaphragm Screws THROTTLE POSITION SENSOR V/R V/B INSPECTION Measure the resistance on the T.P.S. of terminals. Wire Color Full Open Full Close V/R-V/G 4.8~6.2k 4.8~6.2k V/B-V/G 4.16~6.24k 1.47~2.21k V/R-V/B 2.3~3.5k 5.1~7.5k Throttle Position Sensor V/G AUTO BYSTARTER INSPECTION Measure the resistance between the auto bystarter wire terminals. Resistance: 14-20 (10 minutes minimum after stopping the engine) If the reading is not within the limit, replace the auto bystarter with a new one. 4-9