Advertisement
CARB URETOR-BBS
14-2 1
CHOKE VALVE CLOSED
CHOKE VALVE
WIDE OPEN
CHOKE LEVER
CHOKE VALVE
CHOKE OPERATING
Fig. 17-Choke
Operating Link Clearances
make the following check:
(8) With no vacuum applied to the diaphragm,
some clearance should exist between the choke oper-
ating link and the choke lever slot, in both the open
and closed choke valve positions, as shown in (Fig.
17).
This
clearance is necessary to allow the choke
valve to close for starting as well as fully open after
the engine reaches the normal operating temperature.
If a clearance does not exist in both of these posi-
tions, a recheck of the operating link adjustment
should be made.
NOTE: Free movement of the choke valve between
the closed and open positions
is
very necessary.
This free movement should also exist between the
kick and the open choke valve positions with the en-
gine running. If binding does exist, the choke operat-
ing link has been improperly bent and should be cor-
rected.
Choke Unloader (Wide Open Kick)
(1)
Hold the throttle valve in the wide open posi-
tion, insert Tool T109-28 or
"Il,,
drill between the
upper edge of the choke valve and the inner wall of
the air horn, as shown in (Fig. 18).
(2)
If no drag is felt, or
if
too much drag is appar-
ent, bend the unloader tang on the throttle lever, un-
til correct clearance has been obtained.
BEND THROTTLE
NK654
A
3
Fig 18-Measuring
the Choke Unlooder Setting
(wide open kick)
Idle Speed Adjustment (Curb Idle)
To make the idle speed adjustment, the engine
must be thoroughly warmed up. A much more reliable
idle adjustment can usually be obtained if the car has
been driven a minimum of five miles. For the best
results,
it
is recommended that a tachometer be used
in this adjustment. (Before making the idle speed ad-
justment, observe the following precautions:)
Because the alternator can charge at idle speeds
and impose a load on the engine, the headlights
should be turned on. This will assure setting the idle
to compensate for the alternator load. On cars
equipped with automatic transmissions, unsnap the
ball joint connection at the accelerator shaft bell
crank. If this is not done, it is possible that the car-
buretor throttle will be held open against the stop in
the transmission. The carburetor would therefore not
respond to adjustment of the idle speed screw. After
the proper idle speed has been obtained at the carbu-
retor, screw the ball joint connector up or down until
the ball on the bell crank will exactly mate with the
socket. Snap into place.
To make the idle speed adjustment, proceed as fol-
lows:
(1)
Turn the idle speed screw
in
or
out
to obtain
550
r.p.m. (Be sure that the choke valve is fully open
and that the fast idle adjusting screw is not contact-
ing the cam.)
(2) Adjust the idle mixture screw to obtain the
highest r.p.m. While making the adjustment, care-
fully watch the tachometer and notice that the speed
can be decreased by turning the screw in either direc-
Hide quick links:
Advertisement
