Service manual

SERVICE MANUAL • 1975 SCORPION BRUT
I
PILOT SYSTEM (LOW SPEED OPERATION)
(See FIGS. 2-3, 2-4, 2-5)
1. Conditions:
a. The throttle valve is nearly closed.
b. Air velocity through the needle jet is
slow, resulting in insufficient negative
pressure to draw fuel from the needle jet
in the main fuel system.
2. Fuel is metered through the pilot jet.
3. The fuel is mixed with air adjusted to the
proper amount by the air screw.
4. The mixture is mixed with additional air
coming in through the by-pass.
5. Finally the mixture is drawn through the
pilot outlet to mix with air flowing through
the main bore .
FIG. 2-4
AIR JET
AIR SCREW
2-4
NEEDLE JET
AIR FLOW
I I
BY-PASS
~ AIR SCREW
1
I
1
1
I I I I
I I L- - -....,.. - - - - - - - _, I I I I -_ ....... _ _ _ _ ____ I
l ~ -_ ~--:... -_ -_-=--=---::::_ -_ - ~ -~-- -_ -_ -=- -_ -'~
PILOT JET
FIG. 2-3
EMULSION TUBE
IDLE SPEED SCREW
FIG. 2-5