1. GENERAL INFORMATION ZING125 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 Fuel reaches Fuel does not Clogged float oil passage carburetor reach carburetor Clogged fuel filter Clogged charcoal canister Clogged auto fuel valve strainer Remove spark plug and Faulty auto fuel valve passage install it into spark plug Clogged carburetor air balance cap to test spark by tube 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 Normal Low or no Valve clearance too small compression compression Valve stuck open 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 Wet spark plug Flooded carburetor Dry spark plug Throttle valve excessively open Clogged air cleaner 1-15