Troubleshooting - DAELIM NS125DLX Service Manual

20. Troubleshooting

Engine Does Not Start or Is Hard to Start
Engine Output Insufficient
Poor Performance at Low Speed and Idling
Poor Performance at High Speed
Unsatisfactory Operation
Fuel Gauge
Starter Motor
Engine Does Not Start or Is Hard to Start
1. Open the drain screw, and check
fuel flow to the carburetor.
Fuel is supplied.
2. Check spark plugs
Good spark
3. Test cylinder pressure.
Pressure normal
4. Start engine in the following procedure
Engine will not start.
5. Remove spark plugs.
Dry plugs
Fuel not supplied
to the carburetor
weak or no spark
Low cylinder pressure
Engine start but
stops immediately
Plugs wet
Troubleshooting
Cause of Trouble
(1) Fuel tank empty
(2) Fuel tube up to the fuel tank
clogged, or the vacuum tube or fuel
tube up to the inlet pipe clogged
(3) Float valve clogged
(4) Fuel tank cap air hole clogged
(5) Fuel supply pipe frozen
(6) Fuel strainer clogged.
(1) Faulty spark plug
(2) Contaminated spark plug
(3) Faulty CDI unit
(4) Faulty A.C. generator
(5) Disconnected or shorted high
tension cord
(6) Disconnected or shorted ignition coil
(7) Faulty main switch
(1) Piston ring seized
(2) Cylinder and piston ring won
(3) Cylinder and cylinder head cracked
(4) Crank case air leaks
(5) Cylinder head gasket damaged
(1) Manifold air leaks
(2) Inadequate ignition timing
(1) Carburetor flooded
(2) Faulty control box
(3) Throttle valve excessively opened
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