Generic Onyx 50, Service Manual

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Failure Diagnosis
Diagnosis on failure or difficulty in starting engine
Failure or difficulty in starting engine
Check ignition system
Remove the spark plug and check whether there is
carbon fouling between electrode.
Sparkover test for spark plug Eliminate carbon fouling
Weak spark or no spark between electrode Large blue or bluish purple spark between electrode
Screw off spark plug cap and conduct
sparkover test for high tension line
Check whether ignition is timely conducted with
an ignition timing light
Large blue spark Weak spark or no spark
Check whether spark plug and cap are in
good condition
Check power
supply for
ignition
Check whether
short circuit or
open circuit
occurs to
ignition coil Check whether
short circuit or
open circuit occurs
inside the ignition
system
Check whether
CDI ignition
device is in
good condition
Check the compression
pressure of cylinder
with pressure gauge
Check
whether there
is gasoline in
the fuel tank
Normal
compression
pressure
Insufficient
compression
pressure
Add
gasonline
Non-contact ignition system
for electromagnetic motor
1. Check whether short
circuit or open circuit
occurs to ignition coil
2. Check whether short
circuit or open circuit
occurs to trigger coil
1. Check whether CDI
ignition device is in good
condition
2. Check whether flywheels
and trigger coil are
loosened
Screw off the bolt of
carburetor and
check whether there
is gasoline in the
overflow tube