Pontiac tempest 1968 Service Manual page 317

6B-10 1968 P O N T I A C SERVICE MANUAL
. 0 5 0 " . Adjust by turning valve on top of air horn, as
needed.
Fig. 6B-20 Vacuum Break Diaphragm Installed
4. To insure proper end clearance between choke
trip lever and choke rod lever, move choke shaft
horizontally to obtain . 0 2 0 " clearance between the
two levers (Fig. 6 B - 1 8 ) . Then tighten two choke
valve attaching screws securely and stake in place.
5. Install vacuum diaphragm unit and bracket to
side of air horn, retaining with two attaching screws.
Tighten securely.
6. Install choke shaft lever to end of choke shaft
(diaphragm side), aligning flats on lever with flats
on choke shaft. Large side of lever will hang down­
ward and part number identification faces outward
(Fig. 6 B - 1 9 ) and tighten securely.
7. Install connecting rod to vacuum break dia­
phragm plunger by rotating end of rod so rod enters
notch in plunger, ends of rod face inward (Fig. 6 B -
2 0 ) . Install other end of rod into slot in choke lever.
Install horseshoe clip in groove in rod end and pinch
together.
8. Install choke rod to fast idle cam as shown,
then carefully insert upper end of choke rod into
upper choke lever (Fig. 6 B - 2 1 ) . The dog leg of rod
must face towards idle mixture adjusting needle.
9. Attach fast idle cam to throttle body assembly
with fast idle cam screw and tighten securely. The
steps on fast idle cam should face towards idle speed
screw (Fig. 6 B - 2 1 ) .
IDLE VENT ADJUSTMENT (Fig. 6B-2I)
VACUUM BREAK ADJUSTMENT (Fig. 6B-22)
To insure correct initial choke valve opening, just
after engine starting, adjust vacuum break as
follows.
Push vacuum break diaphragm plunger in until
seated, make sure choke valve is held toward closed
position so that connecting rod is at end of slot. In
this position, adjust rod so that gauge will fit between
lower edge of choke valve and inside of air horn
casting, to give a clearance of . 1 6 0 " .
To adjust, bend connecting rod at point shown.
CHOKE ROD ADJUSTMENT (Fig. 6B-23)
With idle screw resting on second step of fast idle
cam and against shoulder of high step, bend choke
PLACE GAUGE
BETWEEN LOWER
EDGE OF CHOKE VALVE
WALL OF AIR HORN
ROD AGAINST
END OF SLOT
PUSH DIAPHRAGM
PLUNGER IN UNTIL
IT SEATS
With idle rpm set to specification, and screw on
low step of cam, the idle vent valve should be open
Fig. 6B-22 Vacuum Break Adjustment