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Diagnosis on abnormal idle speed of engine
Abnormal idle speed of engine
High idle speed
No idle speed
Unstable idle speed
Check compression
pressure of cylinder
Check whether the carburetor
throttle is completely closed with
your hand.
Check whether ignition is
timely conducted with an
ignition timing lamp.
Insufficient
compression pressure
Normal compression
pressure
1.
Check leakage on
outer connections
of the engine.
2.
Check whether the
piston ring is
ruptured or seized
in the groove or
whether it has
enough elasticity.
3.
Check abrasion of
the piston ring and
the cylinder.
Adjust the idle speed of
carburetor.
Check
whether idle
jet is too big.
Check whether the
steel wire rope of
accelerator control
cable is flexible
when being pulled
and whether the
throttle valve
spring is too soft.
Check
whether
the
electrode
gap of
spark plug
is too
small.
1.
Check whether
CDI ignition
device is in
good condition
2.
Check whether
flywheels and
trigger coil are
loosened
Idle speed after
adjustment
No idle speed after
adjustment
The air adjusting
screws of the
carburetor or the
adjusting screws
of throttle valve
are improperly
adjusted.
Check whether the
carburetor idle jet, idle
fuel way and air path are
blocked.
Clean and
clear
Check whether carburetor float is
too high.
Adjust the float
height to standard
value.
1.
Check whether the heat insulator of
carburetor is cracked.
2.
Check whether the fixing nuts of carburetor
are loosened.
3.
Check whether the negative pressure pipe
of fuel switch is broken.
4.
Check whether air leakage occurs to reed
valve.
Adjust the
electrode gap.
Check the proportion
of mixed
combustible gas.
