Pontiac FIREBIRD 1972 Service Manual page 701

ENGINE FUEL 6B-47
1. Thoroughly clean carburetor casting and metal parts
in a clean cleaning solvent.
CAUTION: Vacuum break !nit, gaskets and
pump plunger should not be immersed in sol-
vent. Clean pump plunger in clean gasoline
only.
2. Blow all passages in castings (Fig. 6B-61 through
6B-64) dry with compressed air and blow off all parts
until they are dry.
CAUTION: Do not pass drills or wires through
calibrated jets or passages as they may enlarge
orifices and seriously affect carburetor calibra-
tion.
3. Check all parts for wear. If wear is noted, defective
parts must be replaced. Note especially the following:
a. Check float needle and seat for wear. If wear is
noted, the assembly must be replaced.
b. Check float lip for wear and float for damage.
c. Check throttle and choke shaft bores in throttle
body and cover castings for wear or out of round.
IDLE
PASSAGES
d. Inspect idle adjusting needles (if removed) for
burrs or ridges. Such a condition requires replace-
ment.
e. Inspect fast idle cam. If wear is noted on steps of
cam, it should be replaced as it may upset engine
idle speed during the warm-up period.
f. Inspect pump plunger cup. Replace plunger if cup
is damaged.
g. Inspect power piston and spring for burrs or dis-
tortion. Replace if necessary.
4. Check all filter screens for dirt or lint. Clean and, if
they are distorted or plugged, replace with new parts.
5. Inspect cluster casting. If any parts in castings are
loose or damaged, cluster assembly must be replaced.
6. Use new gaskets in reassembly.
ASSEMBLE
1. Install idle stop screw in throttle lever if removed.
2. If it was necessary to remove the idle mixture needles,
install the idle mixture needles and springs into the
-
throttle body until finger tight. Back out screws 4
turns as a preliminary idle adjustment.
NOTE: Do not install the plastic idle Iimiter
caps furnished until after the idle mixture has
been adjusted on the engine. Refer to Section
6D for setting procedure.
3. Invert the float bowl, then place new throttle body
gasket in position and attach the throttle body with
three screws. Tighten the screws evenly and securely.
FLOAT BOWL
ASSEMBLE
1. Drop steel pump discharge check ball into pump
discharge hole. Ball is 3/16" diameter (do not con-
fuse with aluminum inlet ball). Install pump dis-
charge spring and retainer.
2.
.
Replace cluster main well tubes (307 only) and gas-
ket, tighten screws evenly and securely. Make certain
center screw is fitted with gasket to prevent pump
discharge leakage.
Fig. 68-64 Float Bowl to Cluster Passages
3. Replace main metering jets and power valve.