Pontiac tempest 1968 Service Manual page 322

ENGINE FUEL
6 B - 1 5
Fig. 6B-32 Metering Rod Adjustment
against spring tension, then slide metering rod
out of slot in holder and remove from main meter­
ing jet.
b. To check adjustment back out slow idle
screw and rotate fast idle cam so that fast idle
cam follower is not contacting steps on cam.
c. With throttle valve completely closed, apply
pressure to top of power piston and hold piston
down against its stop.
d. Holding downward pressure on power piston,
swing metering rod holder over flat surface of
bowl casting next to carburetor bore.
e. Use specified gauge and insert between bowl
casting sealing bead (gasket removed) and lower
surface of metering rod holder. Gauge should
have a slide fit between both surfaces, as shown.
(Use gauge .075" for 7028065 carburetor,.085" for
remaining two.)
f. To adjust, carefully bend metering rod holder
up or down at point shown.
g. After adjustment install metering rod and
tension spring.
19. Install air horn gasket on float bowl by care­
fully sliding slit portion of gasket over metering rod
holder. Then align gasket with dowels provided on
top of bowl casting and press gasket firmly in place.
AIR HORN ASSEMBLY AND INSTALLATION
(Fig. 6B-27)
1. Install idle vent valve, if removed.
2. Install choke shaft, choke valve and vacuum
break lever, if removed. Align choke valve, tighten
two retaining screws and stake securely.
3. Install vacuum break diaphragm and plunger
into cavity at side of air horn. With choke valve in
the open position, slide eyelit of plunger rod over
end of vacuum break lever on choke valve.
4. Seat vacuum break diaphragm over sealing bead
on air horn casting. With diaphragm held in place,
carefully install diaphragm cover and two retaining
screws. Tighten screws securely.
5. Install air horn to float bowl by lowering gently
on to float bowl until seated. Install three long and
three short air horn to float bowl attaching screws
and tighten securely.
6. Assemble choke rod to the choke shaft lever.
End of rod points away from air horn casting when
installed properly. Lower end of rod has 45 degree
bend.
7. Install lower end of choke rod into curved slot
in fast idle cam. Steps on fast idle cam should face
fast idle tang on throttle lever.
8. Install upper choke lever to choke shaft. End
of lever faces towards vacuum break diaphragm.
(See Fig. 6B-26). Install choke lever screw. Tighten
securely.
IDLE VENT ADJUSTMENT (Fig. 6B-33)
Set engine idle rpm to specification (solenoid
inactive) and hold choke valve wide open so that the
fast idle cam follower is not hitting the fast idle cam.
Initial idle setting can be made by turning idle screw
in 1 1/2 turns from closed throttle position.
With throttle lever held against the idle screw,
the idle vent valve should be open as specified.
To measure insert plug gauge between top of
air horn casting and bottom of vent valve.
Fig. 6B-33 Idle Vent Adjustment