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CARBURETOR-BBD
1
' / 4
INCH
14-29
delivery while the engine is running. It positions the
choke valve within the air horn by action of the link-
age between the choke shaft and the diaphragm. The
diaphragm must be energized to measure the vac-
uum kick adjustment. Use either a distributor test ma-
chine with a vacuum source or vacuum supplied by
another vehicle. Adjust as follows:
(1)
With the engine
Not
running, open the throttle
valves far enough to allow the choke valve to be moved
to the closed position.
(2)
Disconnect the vacuum hose from the dia-
phragm and connect the hose from the vacuum sup-
ply as shown in (Fig. 14). (A minimum of 10 inches of
mercury (HG) will be required.)
(3) Insert the specified size drill or gauge between
choke valve and the wall of the air horn. Refer to
(Fig. 1). Apply sufficient closing pressure on the choke
shaft lever to provide the smallest choke valve open-
ing possible without distortion of the diaphragm link.
Note that the cylindrical stem of the diaphragm will
extend as an internal spring is compressed. The spring
must be fully compressed for proper measurement
of the kick adjustment.
(4) An adjustment will be necessary if a slight drag
is not obtained as the drill or gauge is being removed.
The adjustment of this opening will require the
removal of the choke operating link.
CAUTION: Damage to the diaphragm and the choke
lever slot can result, if the link is not removed for
the bending operation.
(5) Remove the clip and disengage the choke oper-
ating link from the diaphragm stem, then disengage
the link from the choke lever. (The best bending re-
sults will be obtained by using a vise and
a
pair
of
pliers.)
f n
CHOKE OPERATING LINK
1
V
NK692
Fig. 75-Choke
Operating Link Measurements
(6)
Bend the choke operating link at the angle to
provide the correct choke valve opening.
CAUTION: A correction in the length of the link
of
.010 inch, will result in
a change of
.015 inch in
the choke valve opening.
As an example, if the choke valve opening is 0.015
inch in error, the correction in the link length would
be .010 inch.
A "2" inch micrometer will be helpful in establish-
ing the original length of the link, as shown in (Fig.
15), before completing the adjustment.
(7)
Install the choke operating link and recheck the
choke valve opening, using a guage or drill. Refer to
(Fig. 14).
(8)
Reinstall the vacuum hose to the diaphragm
CLEAR AN
CHOKE
VALVE
CLOSED
I
CHOKE OPERATING
Fig. 74-Measuring
the Choke Vacuum Kick Setting
Fig. 1 &Choke
Operating Link Clearances
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