Chevrolet 70 1969 Series, Shop Manual

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E N G IN E 6-43
Figure 8 — Typical Use of G a u g e to C h e ck C a rb u re to r Float Level on
4 0 1 M a n d 4 7 8 M E n g in e s
1. Insert choke shaft (6) in air horn, locate choke plate
(7) at shaft and install screws (8).
NOTE: Choke shaft (6) must be positioned so
threaded end is as shown in Figure 11 and
choke plate screw heads must be at top. Before
tightening screws (8), close choke plate and
align for best closing. When plate is aligned,
tighten screws securely.
2. Install fast idle lever (10) (when used), using lock-
washer (11) and (12).
3. Install choke lever bushing (5) on choke shaft, with
cut-out over pin in shaft. Place choke lever on bush­
ing, but leave lever clamp screw loose. Slide overtra­
vel spring (3) and retainer (2) on choke shaft with
ends of spring engaging holes in bushing and retainer.
If cotter pin hole in retainer does not line up with
hole in shaft, turn retainer to nearest hole (winding up
spring), then turn retainer two more holes and install
cotter pin (1).
4. While holding choke plate open, locate the upper end
of choke lever (4) 3 7 - 1 / 2 degrees to left of vertical
(viewed from lever end of shaft), then tighten screw to
lock lever to bushing.
5. Install power jet piston (17) in air horn assembly and
stake in place.
6. Place spring (18) on pum p piston (19), then hook pis­
ton rod eye on lever at accelerating pum p shaft (16).
ASSEMBLY OF AIR HORN, MAIN BODY,
AND THROTTLE BODY UNITS
Key numbers in text refer to Figure 1.
1. Firmly support throttle body in m anner to prevent
dam age to throttle plates. Locate gasket (10) at
throttle body assembly, and gasket (5) at main body
assembly. Set main body assembly in place on
throttle body assembly, and use two short screws (2)
to temporarily hold main body in place. Position air
horn assembly on main body as accelerating pum p
piston (12) is carefully guided into pu m p cylinder.
Piston leather must not be creased and lip must not
be turned upward.
2. With holes in all parts aligned, install long bolts (4)
and attach choke tube holder (1) and identification
tag (3) as short screws (2) are insta led. Tighten all
screws (2 and 4) evenly and firmly to seat the parts
solidly.
NOTE: The "special screw" (fig. 1) is not used
on early carburetors.
3. Install accelerating pu m p shaft lever (13, fig. 2) and
secure with lockwasher and nut. Install accelerating
pum p rod (8) with lower end in hole at lever on
throttle driver assembly and upper end engaging cen­
ter slot in pu m p lever as shown in Figure 4. Retain
rod with cotter pin at lower end and flat washer and
cotter pin at upper end.
4. Install fast idle link (6), fitting the keyed end into
lever on choke shaft and lower end of link in slot in
fast idle cam. Install hairpin type lock to retain link
at cam.
5. Install choke control holder (23, fig. 5) at tapped
bosses on throttle body.
6. M ak e fast idle screw adjustment and choke lever ov­
ertravel settings as described under “ C arburetor A d ­
justm ents” in Service Section 6M of this manual.
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L