TROUBLESHOOTING
ENGINE WILL NOT START OR IS HARD TO START
Inspection/Adjustment
Symptom
Probable Cause
Check if fuel reaches carburetor by loosening drain screw
Remove spark plug and install it into spark plug cap to test
spark by connecting it to engine ground
Test cylinder compression
Start engine by follow- ing normal starting procedure
Fuel reaches carburetor
Spark jumps
Normal compression
Engine does not fire
Fuel does not reach carburetor
Weak or no spark
Low or no compression
Engine fires but does not start
Empty fuel tank
Clogged carburetor fuel inlet
t ube, vacuum t ube or fuel t ube
Clogged auto fuel valve
Clogged float oil passage
Clogged fuel tank cap breather hole
Clogged fuel strainer
Clogged fuel filter
Faulty fuel pump
Faulty spark plug
Fouled spark plug
Faulty CDI unit
Faulty A.C. generator
Broken or shorted ignit ion coil
Broken or shorted exciter coil
Faulty ignition switch
Starter motor idles but crankshaft does not rotate
Valve clearance too small
Improper valve and seat cont act
Worn cylinder and piston rings
Blown cylinder head gasket
Flaws in cylinder head
Seized valve
Improper valve timing
Faulty auto bystarter
Air leaking through intake pipe
Incorrect ignition timing
Incorrectly adjust ed pilot screw
Remove spark plug and inspect again
Dry spark plug
Wet spark plug
Flooded carburetor
Faulty auto bystarter
Throttle valve excessively open