164 EMISSION CONTROLS AND FUEL SYSTEM
Holley float level adjustment
check to see that die fuel level reaches the
bottom threads of the sight plug port. A plus
or minus tolerance of Vs2 in. is acceptable.
To change the level, loosen the fuel-inlet
needle locking screw and adjust the nut.
Clockwise lowers the fuel level and counter-
clockwise raises it. Turn the nut Vie of a turn
for each Vie in. desired change. Open the
primary throttle slightly to assure a .stabilized
adjusting condition on the secondaries. There
is no required float drop adjustment.
FAST-IDLE ADJUSTMENT
Early 4150
Bring the engine to normal operating tem-
perature with the air cleaner off. Open the
throttle. Place the fast-idle cam on its high
step and close the throttle. Adjust the fast-
idle screw to reach the specified idle speed.
Late Model 4150 and 4160
Open the throttle and place the choke plate
fast-idle lever against the top step of the fast-
idle cam. Bend the last-idle lever to achieve
the specified throttle plate opening.
Holley accelerator pump adjustment
ACCELERATOR PUMP ADJUSTMENT
Turn off the engine. Block open the throttle
and push down the pump lever. Clearance
between the pump lever arm and the spring
adjusting nut should be 0.015 in. minimum.
Turn the screw or nut to adjust this clear-
ance.
SECONDARY THROTTLE VALVE
ADJUSTMENT
Late Model 4150 and 4160
Close the throttle plates then turn the adjust-
ment screw until it contacts the throttle le-
ver. Advance the screw % turn more.
AIR VENT VALVE ADJUSTMENT
Late Model 4150 and 4160
Close the throttle valve and open the choke
valve so that the throttle arm is free of the
idle screw. Bend the air vent valve rod to ob-
tain the specified clearance between the
choke valve and seat. Advance the idle-speed
screw until it touches the throttle lever then
advance it
IVz
turns.
CHOKE
UNLOADER ADJUSTMENT
Adjustment should be made with the engine
not running. Fully open and secure the
throttle plate. Force the choke valve toward
a closed position, so that contact is made with
the unloader tang. Bend the choke rod to gain
the specified clearance between the main
body and the lower edge of the choke valve.
VACUUM BREAK ADJUSTMENT
Late Model 4150 and 4160 Holley
Secure the choke valve closed and the vac-
uum break against the stop. Bend the vac-
uum break link to gain the specified clear-
ance between the main body and the lower
edge of the choke valve.
