Idle Mixture
NOTE:
The carburetor has been calibrated at the factory, and should not normally need adjustment unless mixture control unit is replaced, carburetor is overhauled, or vehicle fails emission testing.
- Make sure idle speed and ignition timing are set to specifications before proceeding with the following procedure. Remove carburetor from intake manifold. Gain access to mixture adjusting screw pin covering mixture adjusting screw. See Fig 1 . Drive out mixture adjusting screw pin using iron rod .18" (4.5 mm) thick.
- Reinstall carburetor. Connect emission control system hoses and lead wires. Place transmission in Neutral, set parking brake, and block drive wheels.
- Connect tachometer and CO tester to engine. Start engine and adjust idle speed to 850-950 RPM by turning idle speed adjusting screw.
- Adjust CO concentration to 1.5-4.5% by either tightening or loosening idle mixture adjusting screw. See Fig 2 . Readjust idle speed to 850-950 RPM.
- If CO concentration is not within specification, make adjustments again by repeating steps 3) and 4).