Chevrolet Corvette 1963 Repair & Tune-Up Manual page 163

primary throttle valves open, the secondary
throttle-to-bore angle will be SVz
should be 0.017 in.-0.022 in. clearance be-
tween the positive closing shoes on the pri-
mary and secondary throttle levers with the
throttle valves closed.
DISASSEMBLY AND ASSEMBLY
1. Remove the carburetor from the en
gine but do not drain the fuel in the bowl.
Tap the filter nut lightly with a hammer then
remove the inlet nut and gasket and lift out
the filter.
2. Disconnect the choke connector rod,
intermediate choke rod, and throttle rod. Re
move the metering-rod dust cover and vapor
vent arm. Loosen the pump operating arm
and metering-rod arm securing screws, and
withdraw the countershaft.
3. Remove the metering rod arm and link.
Turn each metering rod 180° and lift them
from the anger. Do not lose the two, meter
ing rod discs.
4. Remove the top cover, lifting straight
up so as to avoid damaging the floats, vacuum
piston, or plunger assembly. Be sure the
cover gasket is free of the bowl before lifting
the cover. Mark the floats before removing
them from the cover, to avoid unnecessary
bending during assembly adjustments.
5. Remove the secondary float needle,
seat, and gasket, and group together. Re
move the pump plunger assembly and spring
and soak the leather pump plunger in gaso
line or kerosene to prevent it from drying out.
Turn the vacuum piston Vt turn to disconnect
and remove the piston link.
6. At this time, check the fuel in the bowl
for contamination. Sweep the bottom of the
bowl with a magnet while the fuel is still
present. This will pick up iron oxide dust or
metallic particles. Water contamination will
appear as milky globules at the bottom of the
bowl.
7. Invert the carburetor body and re
move the pump jet cluster and gasket. Tap
out the pump discharge needle. Attach a
in. six-point socket to a six-inch extension and
pry the pump inlet ball retainer and check
ball from the bottom of the pump cylinder
well.
8. Remove the primary metering rod jets
from the pump side of the carburetor. Re
move the secondary main jets but do not mix
them as their orifices are not the same size.
Check the low speed jets to see that they are
angled slightly on installation. The antiper-
EMISSION CONTROLS AND FUEL SYSTEM
colator plugs and bushings and main dis-
0
. There charge nozzles are a press fit and should not
be removed.
buretor body. Remove the idle-mixture
screws and springs, throttle-lever adjusting
screw, washer, and spring. Remove the fast-
idle cam assembly and lockout arm. Remove
the primary/secondary throttle valve connec-
tor rod. Back out the primary throttle shaft
screw and washer and remove the throttle le-
vers. Dislodge the secondary throttle return
spring. Remove the primary and secondary-
throttle valves and shafts. It will be necessary
to file the staked ends of the throttle valve
securing screws before they can be removed.
Remove the choke housing and baffle.
components. Use a carburetor cleaning solu-
tion to wash everything but the coil housing
assembly and pump plunger. Clean the choke
housing assembly in gasoline. Reassembly is
the reverse of this procedure.
Carter AFB Carburetor
The Carter AFB (aluminum four-barrel) car-
buretor is a high performance option found
on the 327 cubic inch Corvette engine from
1963-1965. It is a four-throat downdraft type
and offers improved flow rates over the stan-
dard carburetor. A clean air system reduces
contamination of the choke vacuum circuit
and linkage, and subsequent malfunctioning.
IDLE SPEED AND MIXTURE
ADJUSTMENT
Idle speed and mixture are adjusted with the
engine thoroughly warmed and idling and
with the aid of a tachometer and vacuum
gauge attached to the engine. With the choke
fully off, adjust the idle-speed adjustment
screw to give 475 rpm (450 for automatic
transmission models in Drive). Adjust each
idle-mixture screw until peak steady vacuum
is achieved at the specified rpm.
5
/ie
AUTOMATIC CHOKE ADJUSTMENT
The automatic choke is correctly adjusted
when the scribe mark on the coil housing is
aligned with the center notch in the choke
housing for Powerglide models and one notch
lean with synchromesh.
FLOAT ADJUSTMENTS
Remove the metering rods and the bowl
cover. Align the float by sighting down its side
9. Separate the throttle flange and car-
10. Clean and inspect the disassembled
153