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14-64
CARBURETOR-AFB
to center the small brass main bleed tubes
so
that
they will pass through the holes in the air horn with-
out being damaged.
NOTE:
Be sure the fuel baffles on the air horn,
slide down in front, (bowl side) of the float chamber
baffles, or the air horn will not index correctly with
the main body and can cause the floats to hang up.
Be sure the leather on the plunger does not curl or
wrinkle. Accelerator pump operation will
be
af-
fected if this precaution is not observed.
(4)
Install the 10 air horn attaching screws and
tighten securely. (The two long screws should be in-
stalled in the holes that are located at the air cleaner
mounting surface. The 1 inch screw at the front and
the 1V2 inch at the rear.
The change from the low speed, best fuel economy,
road load mixtures to the richer wide open throttle
full power mixtures is now accomplished in two steps.
This has made
it
possible to secure best low speed
fuel
economy without sacrificing performance in the
intermediate speed range. To do this, there is a new
step-up piston and spring assembly, new metering
rods with three diameters, and new style primary
metering jets, as shown in (Fig. 12).
( 5 )
Slide the step-up piston spring into the piston
cylinders, followed by the step-up pistons and step-up
rods. Install the cover plates and attaching screws
while holding the step-up pistons down in position.
Tighten screws securely.
(6) Slide the choke piston into
its
cylinder in the
air horn, guiding the link into the slot in the choke
valve lever. Align hole, then install attaching cotter
pin. Place
a
new welch plug over cylinder opening
and secure with a ball peen hammer. Check the
fit
of the choke valve in air horn. The valve should be
evenly spaced on all sides. Loosen screws and repo-
sition if necessary.
(7)
Engage the throttle connector rod with the pri-
mary throttle shaft lever, then install hairpin clip. In-
stall clevis clip to the rod and pump arm.
2 STAGE
STEP-UP
PISTON SPRING
COVER
S C R E W
JET-NEW
TYPE
61x171
(8) Engage the lower end of the fast idle connector
rod with the fast idle cam, then swing in an arc to
lock in cam. Slide other end
of
rod into the choke
shaft lever and secure with hairpin clip.
Installing the Vacuum Diaphragm
Inspect the diaphragm vacuum fitting to be sure
that the passage is not plugged with foreign material.
Leak check the diaphragm to determine if
it
has
in-
ternal leaks. To do this,
first
depress the diaphragm
stem, then place a finger over the vacuum fitting to
seal the opening. Release the diaphragm stem. If the
stem moves more than
'Ils
inch in ten (10) seconds,
the leakage is excessive and the assembly
must
be
replaced.
(1) Install the diaphragm assembly on the carbu-
retor and tighten the attaching screws securely.
(2)
Install the choke operating link in position be-
tween the diaphragm plunger (stem) and the choke
lever. Install the clip to secure.
(3) Inspect the rubber hose for cracks, before plac-
ing it on the correct carburetor fitting. Refer to (Fig.
1).
Do not connect the vacuum hose to the diaphragm
fitting until after the vacuum kick adjustment has
been made. (See Carburetor Adjustments.)
ADJUSTMENTS
The following adjustments should be made with
the carburetor on the bench for ease of working, and,
should be made in the following order:
Fast Idle Speed and Cam Position
Ad
justmen
t
The
fast
idle engine speed adjustment should be
Fig. 12-Step-up
Piston, Rod and Jet
Fig. 13-Fast
Idle C a m Position Adjustment
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