Cadillac 60 Series 1963 Shop Manual page 252

FUEL AND EXHAUST
10-17
9. Remove auxiliary throttle assembly by slid-
ing it out of bowl, Fig. 10-15.
23. Rochester 4GC Carburetor
Assembly
NOTE: Carburetor should be completely
cleaned and inspected before assembly as out-
lined in Note 21.
Always use new gaskets when reassembling
carburetor.
a. Throttle Body Assembly
1. Install idle air by-pass screw and spring,
Fig. 10-16. Initial adjustment should be one-
and one-half complete turns from fully seated
position.
2. Install idle mixture screws and springs.
Tighten screws carefully so as not to groove
needles or enlarge seats. Back out each screw
two turns from lightly seated position for initial
mixture adjustment.
b. Throttle Body Installation
1. Invert bowl assembly.
2. Slide auxiliary valve assembly into bowl with
spring cavity opening facing down, Fig. 10-15.
3. Place new throttle body-to-bowl gasket on
bottom surface of bowl.
NOTE: Gasket is not reversible. Largest
projecting tab must be placed on primary side
of bowl, surrounding vacuum passage to power
piston.
4. Place throttle body assembly on bowl and
start three Phillips head screws and lock washers
through gasket into bowl, Fig. 10-16.
5. Install and tighten large center screw and
lock washer.
6. Tighten three outer screws uniformly.
7. Install fast idle cam with attached choke
rod. Tighten screw securely.
c. Bowl Assembly
1. With bowl upright, drop large steel pump
outlet check ball and copper spring into bore
under primary venturi cluster location, Fig.
10-15. Install T-retainer in slot in bore, com-
pressing spring.
2. Position smaller aluminum check ball on
its seat in bottom of pump well.
Idle Mixture
A
Springs - *
s :
Fast Idle
Screw -»^^ff»
S p r i n g '
Fast Idle 2,\
Cam —*"' S^
Pivot c #
Screw
Torsion Spring 1 Speed-Up Lever
S c r e w s \ ! K
\
LL
>'Throttle ' Washer >
'F Opening JJ
Q
L
Vi\
I Center Screw /? \
\ . . / Washer
Connecting _
x
.. i ocrew
Link
£$-«- Throttle
I * Lever
Throttle Body
•i
f
^s Spring
Idle Air
\ By-Pass
% Screw
\ / V
Fig. 10-16 Throttle Body Disassembled
3. Place pump spring in pump bore and com-
press into position with finger pressure.
4. Install idle compensator and new gasket,
using two small self-tapping screws, Fig. 10-14.
5. Install baffles in primary main wells, if
removed, with projections toward primary bores.
Place new gaskets on primary and secondary
venturi clusters and install clusters in bowl,
using three screws and lock washers on each
cluster, Fig. 10-14.
6. Install primary and secondary main metering
jets in bowl. Primary jets have smaller holes
than secondary jets and are installed in pump
side of carburetor bowl.
7. Install power valve and gasket, Fig. 10-14.
8. Install small pump inlet screen and retainer
in bottom of fuel bowl next to pump well.
d. Bowl Cover Assembly
1. Place fuel screen in inlet nut with gasket
and screw into place.
2. Place a small amount of silicone lubricant
on rubber boot and pump plunger shaft.
3. Holding bowl cover upright, install acceler-
ator pump through hole in casting from below
until one flange of boot is above casting with
the other flange below.
4. Install accelerator pump lever into boss
and guide accelerator pump shaft into hole in
lever.
5. Secure lever to boss with large hairpin
clip and pump to lever with smaller hairpin clip.