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NOTE: To make adjustment easier, bend float arm upward at notch in arm before assembly.
9. Install float by sliding float arm under pull clip from front to back. With float arm in pull clip, hold float assembly at toe and install float hinge pin. Needle pull clip should be installed so that it hooks over top of float arm as shown in Figure 2.
NOTE: Do not place pull clip through small
holes in top of float arm - severe flooding will
result.
10. Carefully adjust float level following procedures and specifications listed in the "D" Section of the Delco Carburetor Parts and Service Manual (9X).
11. Install power piston spring in power piston well.
NOTE: If two power piston springs are used,
the smaller spring seats in the center of the
piston and bottoms on the float bowl casting.
The larger diameter spring surrounds the
smaller inner spring to exert additional pressure
on the bottom of the power piston.
12. If the primary metering rods were removed from hanger, reinstall making sure the tension spring is hooked over the top end of each metering rod (See Figure 31, page 22). Install power piston assembly in well with metering rods carefully positioned in metering jets. Press down firmly on power piston to insure engagement of retaining pin in throttle body gasket. NOTE:
a) Some models use a spring clip over top of power piston well. On these, make sure clip is installed and seated.
b) On those which have a split ring retainer around the center of the power piston, carefully compress split ring and push piston down in well until it seats. This properly positions this type retainer.
c) On late models which use the plastic retainer on the top of the power piston, install power piston in well and force plastic retainer into cavity until the edge is flush with top of casting.
NOTE: It may be necessary to tap the plastic retainer lightly in place with a hammer and drift. Make sure the plastic retainer is flush with the top of the float bowl casting.
13. Install plastic filler block over float needle; press downward until seated.
14. Install pump return spring into pump well.
15. Install air horn gasket around primary metering rods
and piston. Position gaskets over two dowels on
secondary side of float bowl.
16. Install pump plunger in pump well.
AIR HORN ASSEMBLY - (Refer to Figure 28, Page 21)
1. Install the following- if removed:
a) Choke shaft, choke valve and (2) attaching screws. Tighten screws securely and stake securely in place.
b) Dashpot plunger rod through air horn and attach to air valve dashpot lever. Make sure clip retainer is installed (where used).
c) Air valve lockout lever (where used) - retain with roll pin. Make sure lever is free from binds. -
d) Normally, the air valve and shaft do not have to be removed from the air horn for cleaning purposes. A repair kit is available which includes a new plastic cam, an air valve torsion spring, and retaining pin. Complete instructions are included also in the kit for installation. (Refer to the "C" Parts Bulletin in the Delco Carburetor Parts and Service Manual for part number application.)
If it was necessary to replace the air valve closing spring and the air valve shaft was removed, install air valve shaft, plastic cam, air valves and four (4) attaching screws. Center air valves, tighten screws and stake in place. Make sure air valve operates freely with no binds. Then install air valve closing spring in air horn cavity. Insert spring pin, adjust air valve closing spring as outlined under adjustment procedures.
NOTE: Whenever a service replacement
throttle body is to be installed on carburetors
(except 4MV Pontiac) equipped for exhaust
emission control, the following adjustment pro
cedures must be performed carefully before
installing air horn.
a. Seat the power piston assembly by pushing
down on top of metering rod hanger.
b. At the front of the throttle body, recessed in
the center, an adjusting screw is visible. The
screw is plugged off except on service throttle
bodies.
c. Back off the screw sufficiently to seat the
power piston in the float bowl.
d. Making sure the power piston assembly is
completely down, turn the adjusting screw
inward until it comes in contact with the power
piston through a lever arrangement (concealed
in the throttle body) and resistance to any
further inward movement of the screw is
noticed. Any further movement of the screw
will begin to raise the power piston and can be
felt.
e. From this point, turn the adjusting screw
inward the exact specified number of turns.
This completes the adjustment. Install the
Welch plug, furnished with the throttle body,
over the adjusting screw and stake in place to
conceal the screw.
ASSEMBLY OF AIR HORN TO BOWL
I. Carefully place air horn assembly on float bowl, aligning vent tubes and accelerating well tubes with proper holes in air horn gasket. On 4MV and 4MC models using a "clipless" vacuum break rod, install vacuum break rod into main vacuum break diaphragm plunger and into air valve lever on air horn before the air horn is lowered onto the float bowl. Position pump plunger stem into hole in air horn and dashpot (where
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