KEEWAY FACT 50 4T Maintenance Manual page 24

Diagnosis on abnormal idle speed of engine
No idle speed
Check
pressure of cylinder
Insufficient
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.
Y
Adjust the float
height to standard
value.
compression Check whether the carburetor
throttle is completely closed with
your hand.
Normal compression
pressure
Adjust the idle speed of
carburetor.
Idle speed after No idle speed after
adjustment adjustment
The air adjusting Check
screws of the carburetor idle jet, idle
carburetor or the fuel way and air path are
adjusting screws
blocked.
of throttle valve
are improperly
adjusted.
N
Check whether carburetor float is
too high.
Abnormal idle speed of engine
High idle speed
Y
Check whether the
Check
steel wire rope of
whether idle
accelerator control
cable is flexible
jet is too big.
when being pulled
and whether the
throttle
spring is too soft.
whether the
N
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.
24
Unstable idle speed
Check whether ignition is
timely conducted with an
ignition timing lamp.
N Y
Check
whether
the
electrode
gap of
spark plug
valve is too
small.
Y
Adjust the
electrode gap.
Y
Clean and
clear
N
1. Check whether
CDI ignition
device is in
good condition
2. Check whether
flywheels and
trigger coil are
loosened
N
Check the proportion
of mixed
combustible gas.