Pontiac tempest 1968 Service Manual page 334

E N G I N E F U E L
6 B - 2 7
Fig. 6B-63 Throttle Body Assy.
1. Thoroughly clean carburetor castings and metal
parts in an approved carburetor cleaner such as
Carbon-X (X-55) or its equivalent.
CA UTION: Any rubber parts, plastic parts, dia­
phragms, pump plungers, should not be immersed
in carburetor cleaner. However, the delrin cam on
the air valve shaft will withstand normal cleaning
in carburetor cleaner.
2. Blow out all passages in castings with com­
pressed air. Do not pass drills through jets or
passages.
3. Inspect idle mixture needles for damage.
4. Examine float needle and diaphragm for wear.
Replace if necessary with new float needle assembly.
5. Inspect upper and lower surfaces of carburetor
castings for damage.
6. Inspect holes in levers for excessive wear or
out-of-round conditions. If worn, levers should be
replaced.
7. Examine fast idle cam for wear or damage.
8. Check air valve for binding conditions. If air
valve is damaged, air horn assembly must be
replaced.
9. Check all throttle levers and valves for binds
or other damage.
ASSEMBLY AND ADJUSTMENT PROCEDURES
THROTTLE BODY ASSEMBLY (Fig. 6B-63)
1. Install idle mixture needles and springs until
seated. Back out needles five turns as a preliminary
idle adjustment.
2. Install pump rod in lower hole of throttle lever
by rotating rod.
FLOAT BOWL ASSEMBLY (Figs. 6 8 - 6 0 , 61 ,
and 62)
1. Install new throttle body to bowl insulator gas­
ket being certain gasket is properly installed over
two locating dowels on bowl.
2. Install throttle body making certain throttle
body is properly located over dowels on float bowl
then install throttle body to bowl screws and tighten
evenly and securely.
Place carburetor on proper holding fixture.
3. Install fuel inlet filter spring, filter, new gasket
and inlet nut and tighten nut to 25 lb. ft.
NOTE: If vacuum break diaphragm was removed
from bracket, slide vacuum break diaphragm be­
tween retaining ears to hold securely.
4. Install fast idle cam on vacuum break assembly.
Be sure fast idle cam actuating pin on intermediate
choke shaft is located in cut out area of fast idle
cam.
5. Connect choke rod to choke rod actuating lever
(plain end) then holding choke rod, with grooved end
pointing inward, position choke rod actuating lever
in well of float bowl and install choke assembly en­
gaging shaft with hole in actuating lever. Install
retaining screw and tighten securely* Remove choke
rod from lever for installation later.
6. Install vacuum hose at tube connection on bowl
to vacuum break assembly.
7. Install air deflector in secondary side of bowl
with notches towards top.
8. Install pump discharge check ball and retainer
in passage next to pump well.
9. Install primary main metering jets.
10. Insert new needle and seat assembly.
11. Install float by sliding float lever under pull
clip from front to back. With float lever in pull clip,
hold float at toe and install retaining pin from pump
well side. Be careful not to distort pull clip (Fig.
6B-61).
12. Adjust float level.
FLOAT LEVEL ADJUSTMENT (Fig. 6B-64)
a. With adjustable T-scale, measure from top
of float bowl gasket surface (gasket removed) to
top of float at toe (locate gaging point 1/16" back
from toe).
NOTE: Make sure retaining pin is held firmly in
place and tang of float is seated on float needle.