KEEWAY RKV125 Instruction And Maintenance Manual page 24

Symptom: Poor idle speed of engine
Diagnosis procedures
Engine has no idle speed.
Check compression pressure in cylinder
Insufficient compression
pressure in cylinder
1. Check leakage
at external
connection parts
of engine; 2.Check
valve timing; 3.
Check if valve
clearance is too
small; 4. Check
tightness between
valve and valve
seat; 5.Check if
piston ring is
broken or stuck
inside the ring
groove or of less
elasticity; 6. Check
wear and tear of
piston ring and
cylinder.
Yes
Adjust float
standard height.
Pull throttle valve of carburetor by hand
and see if it is completely closed.
Compression pressure
in cylinder is normal.
Re-adjust carburetor
idle speed.
Engine has no idle
Engine has idle speed
speed
after adjustment.
adjustment
Air adjusting screw
Check if carburetor idle
of carburetor or
jet, idle oil path and air
throttle adjusting
path are clogged
screw is improperly
adjusted.
No
Check if float is too high.
to
Poor idle speed
Higher idle speed
Yes No
Check
Check if
throttle control
idle jet is
cable can pull
too big.
flexibly in the
cable
and if throttle
spring is too
soft
after
Adjust electrode
clearance.
Yes
No
1. Check if carburetor insulator is cracked; 2. Check
if connecting and fixation nut on carburetor looses; 3.
Check if negative pressure hose on fuel switch is
broken; 4. Check if leaf valve leaks air.
Unsteady idle speed
Use an ignition timing lamp to
check ignition timing of engine
Y
if C
1. Check CDI
heck if
clearance
igniter. 2. Check
of
if
electrodes
jacket flywheel
in spark
plug is too
trigger
small.
looses.
Yes
Check
mixture
of mixed gas.
Clean and dredge.
N
magneto
or
coil
No
ratio