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14-38
CARBURETOR-BBD
1
' / z
INCH
(3) Readjust to
500
rpm with the idle speed screw.
(With air conditioning ON.)
(4)
Turn each idle mixture adjusting screw in the
clockwise direction (leaner) until there is a slight drop
in rpm. Turn each screw out, counterclockwise (richer)
just enough to regain the lost rpm.
This procedure will assure that the idle has been set
to the leanest mixture possible
for
smooth idle.
This
setting is very important.
Since the correct speed was originally set, using the
speed screw, the speed obtained after finding the lean-
est
smooth idle will probably be too fast.
(5) Readjust the speed screw to obtain correct idle
speed. Repeat steps 2 and
4
above if necessary.
Checking Float Setting
I o n
the Vehicle)
(1) Remove the hairpin clip and disengage the ac-
celerator pump rod from the throttle lever and the
pump rocker arm. Disconnect the automatic choke rod
by unsnapping clip.
(2) Remove the air horn attaching screws and lift
the air horn straight up and away from the main body.
Remove the gasket.
(3) Set the float fulcrum pin by pressing a finger
against the fulcrum pin retainer.
There should be enough fuel in the bowl to raise
the floats so that the lip bears firmly against the nee-
dle. Additional fuel may be admitted by slightly de-
pressing the float. If the fuel pressure in the line is
insufficient to force the additional fuel into the bowl,
add the necessary fuel from a clean container.
WARNING: Since the manifolds may be hot, it is
dangerous to spill fuel onto these surfaces. Take
the necessary precautions to avoid spillage.
(4)
With only the pressure from the buoyant float
holding 'the lip against the inlet needle, check the
float setting, using Tool T109-280, or a "T" scale.
There should be
inch from the surface of the bowl
(gasket removed) to the crown of the floats at the cen-
ter.
If
an adjustment is necessary, hold the floats on
the bottom of the bowl, then bend the float lip toward
or away from the needle. Recheck the
inch setting
again, then repeat the lip bending operation as re-
quired.
NOTE: When bending the float lip, do not allow the
lip to push against the needle as the rubber tip
can
be
compressed sufficiently to cause a false
setting which will affect correct level of fuel in the
bowl.
NOTE: After being compressed, the rubber tip is
very slow to recover its original shape. It is very
important that the float lip be perpendicular to the
needle or slanted not more than 10 degrees away
from the needle when the float is set correctly.
-
CHOKE VALVE
WIDE OPEN
NK626
Fig. I L F a s t Idle Speed Adjustment lon the
vehicle)
(5)
After the float has been correctly set, reassem-
ble the air horn.
Fast Idle Speed
(On
the Vehicle)"
To set the fast idle speed on the car, connect a ta-
chometer, then set the curb idle speed and proceed as
follows:
(1) With the engine running and the transmission
in the neutral position, open the throttle slightly.
(2) Close the choke valve about 20 degrees, then
allow the throttle to close. Return the choke valve
to
the open position.
(3) The fast idle adjusting screw should be con-
Fig. 17-Spring
Staged Choke Adjustment
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