New Carburetor Adjustment Procedures

The new tools needed to perform these new carburetor adjustments (See Illustration on final page) are included in the 1983 Essential Tool Package.

M/C Solenoid

FIGURE 3:

1. Remove air horn, mixture control solenoid plunger, air horn gasket, plastic filler block, using normal service procedures.

2. Remove Throttle lever side metering rod. Install Mixture Control Solenoid Gaging Tool J-33815-1, BT-8253-A, or equivalent, over the throttle lever side metering Jet rod guide, and temporarily reinstall the solenoid plunger into the solenoid body (See Figure 3).
3. Holding the solenoid plunger in the DOWN position, use Tool J-28696-10, BT-7928, or equivalent, to turn lean mixture (solenoid) screw counterclockwise until the plunger breaks contact with the gaging tool. The adjustment is correct when the solenoid plunger is contacting BOTH the SOLENOID STOP and the GAGING TOOL (See Figure 3).
4. Remove solenoid plunger and gaging tool, and reinstall Metering Rod and plastic filler block. Invert air horn, and remove rich mixture stop screw from bottom side of air horn, using Tool J-28696-4, BT-7967A or equivalent.

5. Remove lean mixture screw plug and the rich mixture stop screw plug from air horn, using a suitably sized punch. Refer to Page 6C1-10 and 6C1-11 in the 1982 Chassis Service Manual.

6. Reinstall rich mixture stop screw in air horn and bottom lightly, then back screw out 1/4 turn.

7. Remove Idle Air Bleed Cover.

8. Reinstall air horn gasket, mixture control solenoid plunger and air horn to carburetor. Insert External Float Gage J-9789-130, BT-7720 in vent hole and, with Tool J-28696-10, BT-7928, or equivalent, adjust rich mixture stop screw to obtain 4/32" total plunger travel.
9. With solenoid plunger travel correctly set, install Plugs (supplied in service kits) in the air horn, as follows:

a. Install plug, hollow end down, into the access hole to lean mixture (solenoid) screws, and use suitably sized punch to drive plug into the air horn until the top of the plug is even with the lower edge of the hole chamfer. Plug must be installed to retain the screw setting and to prevent fuel vapor loss.

b. Install plug, with hollow end down, over the rich mixture stop screw access hole, and drive plug into place so that the top of the plug is 1/16" below the surface of the air horn casting. Plug must be installed to retain screw setting.

FIGURE 4:

Idle Air Bleed Valve

1. Presetting The Idle Air Bleed Valve

a. Install Idle Air Bleed Valve Gaging Tool J-33815-2, BT-8253-B, or equivalent, in throttle lever side "D" shaped vent hole in the air horn casting. The upper end of the tool should be positioned over the open cavity next to the Idle Air Bleed Valve (See Figure 4).

b. While holding the gaging tool down lightly, so that the solenoid plunger is against the solenoid stop. adjust the Idle Air Bleed Valve so that the gaging tool will pivot over and just contact the top of the valve. The valve is now preset for on-car adjustment (See Figure 4).

C. Remove gaging tool.
2. Adjusting The Idle Air Bleed Valve

a. Connect dwell meter (or use ALCL Tool) to M/C solenoid dwell terminal (6 cylinder scale).

b. Start engine and allow it to reach normal operating temperature.

c. While idling in Drive, use a screwdriver to slowly turn valve counterclockwise or clockwise, until the dwell reading varies within the 35-40~ range, attempting to be as close to 40~ as possible. Perform this step carefully. The Air Bleed Valve is very sensitive and should be turned in 1/8 turn increments only.

d. If, after perfoming Steps b and c above, the dwell reading is not within the 35-40~ range, it will be necessary to remove the plugs and adjust the Idle Mixture Needles.

3. Idle Mixture Needle Plug Removal - ONLY IF NECESSARY:

a. Remove the carburetor from the engine, following normal service procedures, to gain access to the plugs covering the Idle Mixture Needles.

b. Invert carburetor and drain fuel into a suitable container.

c. Place carburetor on a suitable holding fixture, with manifold side up. Use care to avoid damaging linkage, tubes, and parts protruding from air horn.

d. Make two parallel cuts in the throttle body, one on each side of the locator points beneath the Idle Mixture Needle Plug (manifold side), with a hacksaw. The cuts should reach down to the steel plug, but should not extend more than 1/8" beyond the locator points. The distance between the saw cuts depends on the size of the punch to be used.

e. Place a flat punch near the ends of the saw marks in the throttle body. Hold the punch at a 45~ angle and drive it into the throttle body until the casting breaks away, exposing the plug.

The hardened plug will break, rather than remain intact. It is not necessary to remove the plug in one piece, but remove the loose pieces.

f. Repeat this procedure with the other mixture needle.
g. Using tool J-29030-B, BT-7610B, or equivalent, turn both Idle mixture Needles clockwise until they are lightly seated; then turn each mixture needle counterclockwise the number of turns specified:

Carburetor No. of Turns

17082253 3 3/4
17082255 4

h. Reinstall carburetor on engine using a new flange mounting gasket, but do not install air cleaner and gasket at this time.

i. Start engine and run until fully warm, and repeat "Adjusting The Air Bleed Valve", Step 2, on previous page.

j. If unable to set dwell 35-40~, and the dwell is below 35~ turn both mixture needles counterclockwise one additional turn. If dwell is above 40~, turn both mixture needles clockwise one additional turn. Readjust Idle Air Bleed Valve to obtain dwell limits.

After adjustments are complete, seal the Idle Mixture needle openings in the throttle body, using silicone sealant, RTV rubber, or equivalent. The sealer is required to discourage unnecessary adjustment of the setting, and to prevent fuel vapor loss in that area.

Idle Speed

1. Recheck ILC and base idle screw for proper adjustment.*
* If ILC and Base Idle Screw are out of adjustment, refer to Page 6CI-8 in the 1982 Buick Chassis Service Manual for adjustment procedures. Throttle position sensor voltage must be .46 volts at curb idle after ILC and Base Idle Screw adjustments are made.