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PART 20-1-
MAINTENANCE OPERATIONS
20-11
to specification before attempt-
ing to set the fast idle speed.
1. With the engine operating tem-
perature normalized (hot), air cleaner
removed and the tachometer attach-
ed, manually rotate the fast idle cam
until the fast idle adjusting screw
rests on the specified step on the
cam. (Refer to the applicable car-
burettor section for specifications.)
2. Turn the fast idle adjusting
screw inward or outward as required
to obtain the specified fast idle rpm.
ANTI-STALL DASHPOT
where
fitted
1. With the engine idle speed and
mixture properly adjusted, and the
engine at normal operating tempera-
ture, loosen the anti-stall dashpot
lock nut.
2. Hold the throttle in the closed
position and depress the plunger with
a screwdriver blade. Measure the
clearance between the throttle lever
and the plunger tip. Turn the anti-
stall dashpot in a direction to provide
the specified clearance between the
tip of the plunger and the throttle
lever. Tighten the locknut to secure
the adjustment.
DASHPOT LOCKNUT
83134-A
FIG. 19- Dashpot- Typical
Installation
AUTOMATIC CHOKE
THERMOSTATIC SPRING
HOUSING ADJUSTMENT
The automatic choke, where ap-
plicable, has an adjustment to control
its reaction to engine temperature by
loosening the clamp screws that re-
tain the thermostatic spring housing
to the choke housing.
The spring housing can be turned
to alter the adjustment. Refer to the
specifications for the proper setting.
1. Remove the air cleaner assem-
bly, heater hose and mounting bracket
(if so equipped) from the carburettor.
2. Loosen the thermostatic spring
housing clamp retaining screws. Set
the spring housing to the specified
index mark and tighten the clamp
retaining screws.
3. If other carburettor adjustments
are not required, install the heater
hose and mounting bracket (if so
equipped) and the air cleaner assem-
bly on the carburettor.
THERMOSTATIC SPRING HOUSING INDEX MARK
CHOKE HOUSING INDEX MARK
82394-A
FIG. 20-
Automatic Choke
Thermostatic
Spring Housing
Adjustment
-
Typical
CHOKE
PLATE
PULL DOWN
CLEARANCE
STROMBERG WW SERIES
(Figs. 21 and 22)
Apply light closing pressure to
choke valve, then open throttle valves
to wide open position. The choke
valve should open just enough to
allow the insertion of drill gauge
"C" between the choke valve and
wall of air horn. Bend ear on the
throttle lever as required to obtain
correct opening of 0.250".
BEND EAR OF
THROTTLE
(AI reQuired)
FIG. 21-
Choke Plate Pull Down
Clearance -
Stromberg WW Series
Depress diaphragm pull rod to the
full limit of its travel and apply light
upward pressure to choke lever to
take up slack in linkage and to deflect
the modulation spring so that the
choke link is at the end of its slot in
the choke lever.
Hold in this position and check
choke valve opening "D" with a drill
.
gauge.
If opening is not 0.140", bend
choke link at point indicated to
obtain correct setting. After bending
link, ensure choke valve does not
bind in any position.
Preu and Hold Olaphratm
at Its full llmU of Trav ..
FIG. 22- Vacuum Kick-
Stromberg WW Series
MOTORCRAFT MODEL 2100D-2V
CHOKE PLATE PULL DOWN
CLEARANCE
1. Remove the air cleaner.
2. With the engine at normal oper-
ating temperature, loosen the choke
thermostatic spring housing retainer
screws and set the housing 90 degrees
in the rich direction.
3. Disconnect and remove the
choke heat tube from the choke
housing.
4. Turn the fast idle adjusting
screw outward one full turn.
5. Start the engine, then check for
the specified clearance between the
lower edge of the choke plate and the
air horn wall (Fig. 23)
.
6. If the clearance is not within
specifications, turn the diaphragm
stop screw (located on the underside
of the choke diaphragm housing)
clockwise to decrease or counter-
clockwise to increase the clearance.
7. Connect the choke heat tube and
set the choke thermostatic spring
housing to specifications. Adjust the
fast idle speed to specifications.
FAST IDLE CAM CLEARANCE
1. Loosen the choke thermostatic
spring housing retainer screws and
set the housing 90 degrees in the rich
direction.
2. Position the fast idle speed screw
at the kickdown step of the fast idle
cam. The kickdown step is identi-
fied
by
a V stamped on the cam
(Fig. 24).
On the 351-C engine, a two-piece
fast idle lever is used to provide
clearance between the lever and man-
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