KYMCO ZX Service Manual page 21

2
. GENERAL INFORMATION
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.
Remove spark plug and
install it into spark plug
cap to test spark by
connecting it to engine
ground.
Test cylinder
compression (using a
compression gauge).
Check carburetor for
clogging.
Check ignition timing.
Check carburetor air
screw adjustment.
Inspection/Adjustment
Check carburetor
gasket for air leaks.
2-17
Fuel reaches
carburetor
Plug not fouled or
discolored
Good spark
Normal
compression
Not Clogged
Correct timing
Correctly adjusted Incorrectly adjusted
Symptom
Fuel does not
reach carburetor
Plug fouled or
discolored
Weak or inter-
mittent spark
Abnormal
compression
Clogged
Incorrect timing
ZX / SCOUT
• Empty fuel tank
‚ Clogged float valve
ƒ Clogged fuel filter
„ Faulty auto fuel valve
• Fouled spark plug
‚ Incorrect heat range plug
• Fouled spark plug
‚ Faulty CDI unit
ƒ Faulty A.C. generator
„ Faulty ignition coil
... Broken or shorted high
tension wire
† Faulty ignition switch
• Worn cylinder and piston rings
‚ Blown cylinder head gasket
ƒ Flaws in cylinder head
„ Faulty reed valve
... Seized piston
• Clogged carburetor jets
• Faulty CDI unit or A.C.
generator
‚ A.C.G. flywheel not aligned
• Mixture too rich (turn screw
out)
‚ Mixture too lean (turn screw
in)
Probable Cause