Daelim S4 50cc Service Manual - Mojo

18. TROUBLESHOOTINGENGINE WON’T START OR HARD TO START ··········· 18-1ENGINE STALLS, HARD TO START, ROUGH IDLING··········18-2POOR PERFORMANCE AT LOW SPEED AND IDLING ········ 18-3POOR OPERATION ·····················18-4ENGINE WON’T START OR HARD TO STARTCAUSE OF TROUBLEOpen the drain screw, and check fuelflow to the carburetor.Fuel is suppliedCheck the spark plug.Good sparkMeasure the cylinder compression.Compression normalStart the engine in the followingprocedure.Engine doesn’t start.Remove the spark plug, and recheck it.Dry spark plugRestart the engine in the followingprocedure.Engine startsCompletionFuel not suppliedto the carburetor.Weak or no spark.Low or no cylindercompression.Engine starts butstops immediately.Spark plug wet.Engine won’t start.·No fuel to fuel tank.·Disconnected or damaged fuel pumpnegative pressure tube.·Clogged fuel tube.·Clogged float valve.·Clogged fuel strainer.·Clogged fuel tank cap.·Fuel pump malfunction.·Faulty spark plug.·Contaminated spark plug.·Faulty A.C. generator.·Disconnected or shorted hightension cord.·Disconnected or shorted ignition coilwire.·faulty ignition switch.·Faulty CDI unit.·Seized piston ring.·Faulty valve clearance adjustment.·Worn cylinder or piston ring.·Leaking cylinder gasket.·Warped or cracked cylinder head orcylinder.·Carbon deposited on spark plug.·Idle speed misadjusted.·Faulty ignition timing.·Clogged air cleaner.·Lean fuel mixture.·Flooded carburetor.·Throttle valve excessively opened.·Contaminated or clogged air cleaner.·Rich fuel mixture.·Recheck the engine.