Chevrolet Corvette 1963 Repair & Tune-Up Manual page 159

150 EMISSION CONTROLS AND FUEL SYSTEM
or uneven jetting will result. Always use new
gaskets and adjust the float.
THROTTLE LINKAGE/CABLE
ADJUSTMENT
Four Barrel Carburetors
7963-67
Adjust the length of the throttle linkage to
ensure full opening of the throttle plates. Turn
the threaded swivel at the throttle so that with
the accelerator pedal fully depressed and the
carburetor throttle valve fully open, the
threaded swivel will freely enter into the
throttle lever. The lever should then be
turned two full turns to lengdien the control
rod.
7968-72
Loosen the accelerator cable clamp bolt at the
carburetor bracket. Block the accelerator
pedal in the fully depressed position. Open
the carburetor throttle fully and tighten the
cable clamp bolt to 45 in. ibs.
1973-84 (Including TBI)
Throttle cable adjustments are not possible
on these models.
Three, Two Barrel Carburetors
7967-69
Loosen the cable clamp, then fully depress
the accelerator pedal and fully open the
throttle plate of the primary carburetor.
Torque the cable clamp bolt to 45 in. Ibs.
Bring the engine to operating tempera-
ture, set the idle to specifications, and turn it
off. Bottom the clevis pin in the throttle slot
of the primary carburetor and adjust the sec-
ondary closing rod of the rear carburetor so
that it lacks Vz a rod diameter of being long
{^Adjuit fronl jecondory (^Adju*t rear secondary doling rod so thai
dosing rod *o that it it fatli 1 /2 rod dia. ihort entering
iuit enters hole, hole. Imtofl in hoU Pwitsd to itep^
Three, two-barrel carburetor linkage adjustment
enough to freely enter the rear secondary
throttle hole. Connect the rod. Adjust the
forward secondary rod so that it barely enters
the throttle lever hole. Connect the rod and
check the linkage operation to be sure the
plates close completely.
Carter WCFB Carburetor
The Carter WCFB is the standard carburetor
on 1963-1965 Corvettes.
Functionally, it is two, dual carburetors
mounted in a single housing and is comprised
of four basic components: choke housing, top
cover, main body, and throttle flange. The
metering rods, accelerator pump, and choke
are located in the primary side of the carbu-
retor body. It has the five conventional sys-
tems: float, low speed, high speed, accelera-
tor pump, and choke.
IDLE SPEED AND MIXTURE
ADJUSTMENTS
Idle speed and mixture adjustments are best
accomplished using a tachometer and vac-
uum gauge. Make this adjustment with the
air cleaner installed.
Bring the engine to operating tempera-
ture, check to see that the choke is fully off,
and adjust the idle-speed adjustment screw
to give 475 rpm (450 on automatic transmis-
sions in Drive range). Adjust the idle-mix-
ture adjustment screws separately until peak
vacuum and rpm are indicated on the vac-
uum gauge and tachometer.
An alternative method is to set the idle-
mixture screws lean to a beginning, rough
idle, then back screws out (enrichen) % turn.
Never bottom the idle-mixture adjustment
screws or possible damage to the needle seat
may result.
AUTOMATIC CHOKE ADJUSTMENT
The choke is correctly set when the index
mark on the plastic cover aligns with the cor-
responding mark on the choke housing. The
introduction of dirt, gum, water or carbon into
the choke housing or vacuum passage can
detrimentally affect engine performance.
Check this system periodically and clean if
necessary.
INTERMEDIATE CHOKE ROD
ADJUSTMENT
The intermediate choke rod adjustment re-
quires the removal of the choke coil housing
assembly, gasket, and baffle plate. Open the