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14-42
CARBURETOR-WW3
the same bore from whence removed.
(3) Remove the screws, that hold the throttle
valves to the throttle shaft, then slide the valves out
of the throttle shaft.
CAUTION:
These screws are staked on the opposite
side and care should be used at removal so as not
to break the screws in the shaft.
(4)
Slide the throttle shaft out of the throttle body.
(5) Install the new throttle shaft and lever in the
throttle body. The fast idle lever should rest against
the idle speed adjusting screw.
The idle speed adjust-
ing screw must
be
backed out when seating the
valves in the following operation.
The "dash" stamped on the valves must be toward
the idle port and visible from the top of the throttle
body when valves are installed.
(6) Slide the valves in position through the throt-
tle
shaft, then insert
NEW
screws, but do not tighten.
Hold the valves in place with the fingers. (Fingers
pressing on the high side of valves.)
(7) Tap the valves lightly with a screwdriver to seat
in the throttle bores. Holding the valves in this posi-
tion, tighten screws securely and stake by squeezing
with pliers.
(8) Install the two idle mixture adjusting screws
and springs in the throttle body. (The tapered portion
must be straight and smooth.) If the tapered portion
is grooved or ridged, a new idle mixture adjusting
screw should be installed to insure having correct
idle mixture control.
Idle Mixture Screw Adjustment
Do
not use a screwdriver.
The adjustment should be
made with the fingers. Turn the idle mixture adjusting
screw lightly against its seat, then back
off
one full
turn for approximate adjustment.
Reassembling the Carburetor
Main Body
(1)
Place the main discharge jets (or tubes) firmly
on Tool 73608, as shown in (Fig. 9). Slide them into
DIAGONAL CUT TOWARD
OPPOSITE SIDE
OF SMALL VENTURI
.-
-
l
e
.
Y
KH
437
Fig. 9 4 n s t a l l i n g M a i n Discharge Jets for tubes)
position in the main body. Be sure the opening in the
end of tube (diagonal cut end) is facing the opposite
side of the small venturi.
These two jets must
be
seated firmly in the main body.
(2) Insert the main metering jets in the body over
the discharge jets (or tubes) just installed. Tighten
se-
curely, using Tool 73606. See (Fig. 7).
(3) Slide new copper gaskets in the main jet plug
openings, then insert the plugs and tighten securely.
(4)
Place the assembled throttle body on the in-
verted main body and position the insulator. Install
screws and lockwashers, then tighten securely.
(5) Invert the carburetor and place on repair block
C-3225, then install the power by-pass jet and new
gaskets.
The change from the lean road load mixture to the
richer wide open throttle maximum power mixture is
made with an intermediate step. This is accomplished
with a spring loaded two position power jet, actuated
by vacuum on the power jet piston. The purpose of
this two stage action is to secure best fuel economy
in the lower road load speed range without sacrificing
performance in the intermediate speed range.
During initial or part throttle operation, the vac-
uum above the piston is sufficient to overcome the
compression spring and hold the piston in the up po-
sition. As the throttle valves are opened the manifold
vacuum drops and the piston compression spring
moves the piston down to open the first stage valve
(upper) of the power by-pass jet, as shown in (Fig.
12). This meters additional fuel through the upper
hole, into the main metering system.
With increased demand for power and a further
drop in vacuum, the piston moves down an additional
amount to open the second stage valve (lower) as
shown in (Fig. 12), and meters an additional amount
Fig.
I
W n s t a l l i n g Accelerator Pump Check Ball
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