KEEWAY FACT 50 4T Maintenance Manual page 22

The spark plug insulators are black;
the exhaust muffler emits black
smoke or causes backfire if the
engine works at low speed; bad
acceleration property; instable idle
speed; flameout probability;
works normally at high speed.
Mixed combustible gas
is too dense.
1. Check whether the air filter is
blocked.
2. Check whether the startup device
for carburetor (startup & enrichment
system) works normally.
3. Check whether the carburetor float
is too low.
The spark plug insulators are brown
Normal combustible gas mixture
it
Check whether the cylinder
outlet or the exhaust muffler
is blocked due to accumulated
carbon fouling.
1. Check
2. Check whether fuel in the
3. Check whether the fuel filter
4. Check whether the fuel pump
5. Check whether the lubricant
22
Remove the spark plug; check the
colors of spark plug insulators
and judge the proportion of
mixed combustible gas based on
abnormity
Check
lubrication system
Lubrication system
of the two-stroke
engine
fuel level in
crankcase.
crankcase has low viscosity or
is dirty.
is blocked.
works normally.
channel is blocked.
The spark plug insulators are
white; the engine may intermit
during acceleration;
carburetor generates backfire;
insufficient power of engine
the Mixed combustible
gas is diluted.
1. Check whether the
fuel switch works
normally.
2. Check whether the
carburetor float is too
high.
3. Check whether the
measuring jets and
the
drill ways in the
carburetor
blocked.
the
are