quannon 125 Workshop-manual : Page 16

          1. GENERAL INFORMATION                                                                QUANNON 125
 TROUBLESHOOTING

 ENGINE WILL NOT START OR IS HARD TO START


                                                Symptom
  Inspection/Adjustment                                                    Probable Cause


  Check if fuel reaches
 carburetor by loosening
       drain screw                                                      Empty fuel tank
                                                                        Clogged fuel line between fuel
                                                                        tank and carburetor
                                                                        Clogged float oil passage
                                  Fuel reaches          Fuel does not   Clogged fuel filter
                                carburetor           reach carburetor   Clogged charcoal canister
                                                                        Clogged auto fuel valve strainer
                                                                        Faulty auto fuel valve passage
 Remove spark plug and                                                  Clogged carburetor air balance
 install it into spark plug                                             tube
   cap to test spark by
 connecting it to engine
            ground                                                      Faulty spark plug
                                                                        Fouled spark plug
                                                                        Faulty CDI unit
                                Spark jumps          Weak or no spark   Faulty pulser coil
                                                                        Faulty exciter coil
                                                                        Faulty ignition switch
                                                                        Broken or shorted ignition coil
                                                                        wire
       Test cylinder
       compression
                                                                        Faulty or slipping clutch
                                                                        Valve clearance too small
                                  Normal               Low or no        Valve stuck open
                                compression            compression      Worn cylinder and piston rings
                                                                        Leaking cylinder head gasket

 Start engine by follow-ing
       normal starting
         procedure
                                                                        Faulty choke control system
                              Engine does not        Engine fires but   Leaking intake manifold
                                     fire              does not start   Incorrect ignition timing
                                                                        Incorrectly adjusted pilot screw


 Remove spark plug and
    inspect again

                                                                        Flooded carburetor
                               Dry spark plug         Wet spark plug    Throttle valve excessively open
                                                                        Clogged air cleaner




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