Air/Fuel Mixture: Adjustments

Fig. 6 Location of idle speed adjusting screw.:

The mixture adjusting screw is recessed into the throttle body and sealed with a hardened concealment plug which prevents tampering during normal tune up procedures. If it is evident that idle mixture requires adjustment, remove concealment plug as outlined in ``FUEL SYSTEM''.
1. Reinstall carburetor onto engine.
2. Disconnect electric cooling fan electrical connector, start engine and allow to reach normal operating temperature, then shut engine Off.
3. Disconnect battery ground cable for approximately 3 seconds, then reconnect it.
4. Disconnect oxygen sensor connector.
5. With lights and all accessories Off and transaxle in Neutral, start engine and accelerate to 2,000 - 3,000 RPM for at least 5 seconds.
6. Allow engine to idle for approximately 2 minutes.
7. Alternately adjust idle speed (SAS-1) and mixture adjusting (MAS) screws, Fig. 6, to obtain a CO reading in the .1 - .3 % range without causing engine to misfire.
8. Reconnect oxygen sensor connector, then check and adjust curb idle speed as required.
9. Install new concealment plug in throttle body.