b. Be sure any carbon deposits are removed from
bore, especially where throttle valve seats in
casting.
c. Blow out all passages with compressed air.
2. Disassembly of Carburetor-Up Draft
d. Replace all worn and damaged parts. Always
a. Remove carburetor from engine.
use new gaskets
b. Remove bowl cover and gasket.
c. Remove float pin, float, needle, and needle
seat. Check float pin for wear.
d. Remove idle mixture screw ("A", figure 4) and
high speed adjustment screw ("D", figure 4) and
springs. Do not remove choke valve and shaft
unless replacement of these parts is necessary
3. Cleaning Carburetor Parts
a. Clean all parts in solvent. Gum is easily
removed with an alcohol or acetone solvent.
4. Assembly of Carburetor--Up Draft
a. Install throttle shaft and valve. Elongated side
of valve should be towards top.
b. Install needle seat. A 5/16 socket should be
used.
Caution:
Do not over tighten. Torque to 25
to 30 inch-pounds.
c. Install needle, float. and float pin.
d. Set float level. With bowl cover casting inverted
and float resting lightly against needle in its
seat, there should be 7/16 clearance between
machined surface casting and free end of float
(side opposite needle seat).
Figure 4
e. Adjust by bending lip of float with small
screwdriver.
Up-Draft Carburetor
f. Install new bowl cover gasket, bowl cover and
A - Idle Adjustment Screw
D - High Speed Adjustment
bowl cover screws. Tighten securely.
Screw
B - Fuel Line
E - Governor Arm
g. Install high speed adjustment screw ("D" figure
C - Carburetor Bowl
F - Choke Lever
4.) Turn in until screw seats in nozzle and back
G - Idle Speed Screw
out two turns.
h. Install idle mixture screw ("A", figure 4.) Back
out approximately 1/2 turns after seating lightly
against jet.
i. Install idle speed regulating screw and spring.
Adjust desired idling speed with engine running.
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