KEEWAY RKV125 - Idle Speed Malfunctions

Symptom: Poor idle speed of engine
Diagnosis procedures
N
Y
No
Yes
Yes
Poor idle speed
Higher idle speed
Engine has no idle speed.
Unsteady idle speed
Check compression pressure in cylinder
Pull throttle valve of carburetor by hand
and see if it is completely closed.
Use an ignition timing lamp to
check ignition timing of engine
Insufficient compression
pressure in cylinder
Compression pressure
in cylinder is normal.
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.
Re-adjust carburetor
idle speed.
Check if
idle jet is
too big.
Check if
throttle control
cable can pull
flexibly in the
cable jacket
and if throttle
spring is too
soft
1. Check CDI
igniter. 2. Check
if magneto
flywheel or
trigger coil
looses.
Engine has idle speed
after adjustment.
Engine has no idle
speed after
adjustment
Air adjusting screw
of carburetor or
throttle adjusting
screw is improperly
adjusted.
Check if carburetor idle
jet, idle oil path and air
path are clogged
Clean and dredge.
Check if float is too high.
Adjust float to
standard height.
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.
Adjust electrode
clearance.
Check
mixture ratio
of mixed gas.
No
No
Yes
Yes
No
Check if
clearance
of
electrodes
in spark
plug is too
small.