grand dink 125 mmc 1 Manuale-dofficina : Pagina 22

          1. GENERAL INFORMATION                                                              GRAND DINK 125/150



 ENGINE LACKS POWER

 Inspection/Adjustment                                Symptom                   Probable Cause
 Start engine and
 accelerate lightly for                                                         Clogged air cleaner
                                                                                Restricted fuel flow
 observation                                                                    Clogged fuel line between fuel
                                    Engine speed           Engine speed does    tank and carburetor
                                    increases              not increase         Clogged exhaust muffler
                                                           sufficiently         Faulty auto bystarter
 Check ignition timing                                                          Split carburetor vacuum piston
 (using a timing light)                                                         diaphragm

                                    Correct timing          Incorrect timing    Faulty CDI unit
                                                                                Faulty A.C. generator
 Check valve clearance
                                                                                Improper valve clearance
                                        Correct                   Incorrect     adjustment
                                                                                Worn valve seat (valve stem too
                                                                                protruding
 Test cylinder compression
                                                                                Improper valve and seat contact
                                     Normal                     Abnormal        Worn cylinder and piston rings
                                     compression                compression     Blown cylinder head gasket
                                                                                Flaws in cylinder head
 Check carburetor for                                                           Improper valve timing
 clogging

                                     Not Clogged                  Clogged       Clogged carburetor jets

 Remove spark plug and
 inspect
                                  Plug not fouled or        Plug fouled or      Fouled spark plug
                                  discolored                discolored          Incorrect heat range plug
 Remove oil dipstick and
 check oil level and condition
                                                                                Oil level too high
                                    Correct and not             Incorrect or    Oil level too low
                                    contaminated                contaminated    Oil not changed
 Remove cylinder head oil
 pipe bolt and inspect
                                 Valve train lubricated   Valve train not       Clogged oil pipe
                                 properly                 lubricated properly   Faulty oil pump
                                                                                Insufficient coolant
 Check if engine overheats                                                      Faulty thermostat
                                                                                Worn cylinder and piston rings
                                                                                Mixture too lean
                                    Engine does not         Engine overheats    Poor quality fuel
                                    overheats                                   Excessive carbon buildup in
                                                                                combustion chamber
                                                                                Ignition timing too early
 Rapidly accelerate or run                                                      Air in cooling system
 at high speed
                                                                                Excessive carbon build-up in
                                                                                combustion chamber
                                 Engine does not knock       Engine knocks      Poor quality fuel
                                                                                Clutch slipping
                                                                                Mixture too lean
                                                                                 Ignition timing too early


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