2-12 PERIODIC MAINTENANCE
3. Adjust pilot screws in small increments until a stable en-
gine speed is achieved.
NOTE :
Turning pilot screw inward (clockwise):
• The fuel / air mixture becomes leaner.
Turning pilot screw outward (counterclockwise):
• The fuel /air mixture becomes richer.
NOTE :
There are two types of carburetor as follows :
(A) . Carburetor with covered pilot screw
The pilot screw turns open are preset at factory and the
screw is covered by plate.
Do not try to remove the cover over the pilot screw.
(B) . Carburetor with uncovered pilot screw
For this type of carburetor, the pilot screw turns open
are adjustable.
1. Turn the pilot screw to bring it to the standard specifica-
tion. (for applicable carburetor only)
Pilot screw initial setting
DF25 1-½ turns open
DF30 1-½ turns open
NOTE :
When turning pilot screws fully in, lightly seat them only. Do not
over tighten to avoid damaging needle valve and seat.
2. Turn the idle adjusting screw.
• Turning inward : Engine speed becomes higher
(clockwise)
• Turning outward : Engine speed becomes lower
(counterclockwise)
3
2
3
1
2
3
1. Idle adjusting screw
2. Throttle valve screw
3. Pilot screw
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