(1) Applies only on model 4160 with
mechanical secondarys. Check the choke unloader
adjustment. Hold the choke plate closed and the
throttle fully open. The correct clearance from the
choke plate to the back of the main body must be
a minimum of 3/16.
|(4) After the engine reaches its normal
operating temperature, adjust the idle speed screw
to idle the engine at the specified rpm.
|(5) First set one of the two idle adjusting
needles for the highest steady manifold vacuum
reading. If a vacuum gage is not available, obtain
the smoothest running, maximum idle speed by
turning the idle adjusting needle in until the rpm
begines to drop off, then backing the needle off
over the "high spot" until the rpm again drops
off. Set the idle adjusting needle halfway between
these two points for a satisfactory idle mixture
setting. Then repeat the procedure with the other
needle. Should these adjustments show an increase
in idle rpm, reset the idle speed screw to obtain
the specified idle rpm and adjust the idle adjusting
|See Figure 41 for the correct method
for correcting this clearance.
|C. ADJUSTING THE DASHPOT - The dash
pot, on carburetors for engines equipped with
automatic transmissions, are to be adjusted after
idle speed and mixture settings have been com
pleted. Loosen the dashpot screw and turn the
complete dashpot in the direction desired. Check
the Holley Catalog Sheets for the clearance
between the dashpot and primary throttle lever.
|Figure 41. Correcting Choke Plate Clearance|
|D. ADJUSTING THE AUTOMATIC CHOKE|
|3. ADJUSTMENTS ON THE VEHICLE|
|(1) The automatic choke is accurately set
at the factory to give the best possible all weather
operation. To return the choke to the original
setting, line up the index mark with proper speci
|A. ADJUSTING FAST IDLE SCREW- The
fast idle cam screw should just touch the lowest
step of the fast idle cam, at curb idle. This
adjustment should be made before adjusting the
idle adjusting needles.
|(2) If for some reason a richer or leaner
mixture during the warm-up period is desired, it
can be obtained by rotating the thermostat cover.
Never set the index mark on the cover more than
two graduations off the specified settings.
|B. ADJUSTING THE IDLE|
|(1) Adjustments, to be precise and ac
curate, must be made when the vehicle is on level
|E. EXTERNAL FUEL LEVEL ADJUST
MENT - For models with external fuel level
|(2) Seat the idle adjusting needles lightly
and back each off a full turn if there is any
doubt about this not having been done during
|(1) Check the fuel pump pressure before
altering the fuel level.
|(2) With the air cleaner removed andthe
ignition "off", remove the sight plug (Figure 42)
and then remove the bowl lower attaching screw
farthest from the fuel inlet (Figure 43).
|Care must be taken when seating the idle
adjusting needle not to turn the screw
tight against the seat, grooving the tip of
the needle. If the needle becomes grooved,
a smooth idle cannot be obtained.
|(3) Drain off the gasoline in a shallow
pan using extreme care not to spill gasoline and
create a fire hazard.
|(3) Start the engine and allow the opera
ting temperature to reach normal.
|(4) Re-install the fuel bowl screw.|