Chevrolet 10 series 1973, Overhaul Manual

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6 M - 1 8 CARBURETORS
Fig. V4--Removing Pum p Discharge Spring Retainer
the main wells by using a pair of needle nosed
pliers. Be careful not to distort the plastic main well
inserts.
6. Invert carburetor and remove three large throttle
body to bowl attaching screws. Throttle body and
gasket may now be removed.
NOTE: Do not tamper with the idle mixture
needle with a limiter cap unless performing
an overhaul or due to needle damage. This
has been set to test requirements by the
manufacturer.
7. Further disassembly of the throttle body is not
recommended. If the idle mixture needles are
damaged, or need replacement or the idle mixture
channels have to be cleaned, the plastic limiter cap
should be broken away from mixture screws as new
ones are provided in the repair kit.
IMPORTANT: Before removing idle mixture
needle, be certain to count number of turns
to bottom this old idle mixture needle. This is
required so that when it is necessary to install
a new needle, you may bottom the new
needle and then back off the same number of
turns it took to bottom the old needle.
8. Remove idle mixture needle and spring, if required.
9. Hot Idle Compensator - where used: Remove two
screws retaining hot idle compensator and remove
compensator assembly and gasket from venturi
area.
Cleaning and Inspection
CAUTION: Any rubber parts, plastic parts
(including float assembly), diaphragms, pump
plungers, electric parts and solenoids, should
not be immersed in carburetor cleaner.
The carburetor should be cleaned in a cold immersion
type cleaner.
1. Thoroughly clean carburetor castings and metal
parts in an approved carburetor cleaner.
CAUTION: Any rubber parts, plastic parts,
diaphragms, pump plungers, electric parts and
solenoids, should not be immersed in carburetor
cleaner. However, the air horn which has the
pressure relief valve will withstand normal
cleaning in carburetor cleaner. Make sure the
cleaning solution is thoroughly removed from
pressure relief valve area.
2. Blow out all passages in castings with compressed
air. Do not pass drills through jets or passages.
3. Inspect idle mixture needle for damage.
4. Examine float needle and seat assembly for wear.
Install a new factory matched set if worn.
5. Inspect upper and lower casting sealing surfaces for
damage.
6. Inspect holes in levers for excessive wear or out of
round condition. If levers or rods are worn they
should be replaced.
7. Examine fast idle cam for excessive wear or
damage.
8. Check throttle and choke levers and valves or binds
and other damage.
9. Replace filter element.
10. Check all springs for distortion or loss in tension,
replace as necessary.
ASSEMBLY AND A D JU STM EN TS
Assembly of Float Bowl and Throttle Body
1. If removed, install the idle mixture adjusting
needles and springs into throttle body until finger
tight. Back out screws four turns as a preliminary
idle adjustment.
New Part Replacement
If a new throttle body is being replaced, install and
bottom the new idle mixture needle and back off four
turns. Do not install plastic limiter cap at this time until
proper screw settings have been made.
After completing assembly of the carburetor, and when
installed in the vehicle, adjust the mixture screw to
achieve the idle speed and idle mixture settings as
outlined under "Additional External Settings and
Adjustments".
NOTE: Do not install the new plastic limiter
caps provided until the idle mixture has been
adjusted with the carburetor installed on the
engine, per instructions in the Service
Manual.
new red plastic idle mixture needle limiter cap is
provided in the carburetor repair kit and also in the idle
OVERHAUL MANUAL