J. Adjust Idle Speed & Mixture Screw (If Necessary)

J. Adjust Idle Speed & Mixture Screw (if necessary)

1. Inspect the carburetor to determine if the concealment plug at the idle mixture adjusting screw (MAS) was previously removed and not reinstalled. If the plug is missing, skip steps 2 through 6. If the plug is present, proceed to step 2.

2. Remove the carburetor from the engine.

3. Clamp the carburetor in a vise with the idle mixture adjusting screw (MAS) facing up. (Make sure to protect the gasket surface from the vise jaws.)





4. Drill a 5/64 in. (2 mm) pilot hole in the bottom area of the casting surrounding the idle mixture adjusting screw (MAS), then redrill the hole-to 1/8 in. (3 mm) (Figure 20).

5. Insert a blunt pin punch into the hole and drive out the plug.

6. Install the carburetor on the engine.

7. Start the engine and warm it to normal operating temperature.

8. Check any radio station presets and record them for reference. Turn off the ignition and disconnect the battery negative cable for about 3 seconds. Reconnect the battery cable.

9. Make sure that all lights and accessories are off and the transmission is in neutral for this adjustment.

10. Disconnect the exhaust oxygen sensor connector.

11. Start the engine and run it for at least 5 seconds between 2000 and 3000 RPM.

12. Run the engine at idle for 2 minutes.





13. Set the idle CO to 0.1 to 0.3% at the specified idle speed (750 RPM) by adjusting the idle speed adjusting screw No.1 (SAS-1) and the idle mixture adjusting screw (MAS), (Figure 21).

14. Reconnect the exhaust oxygen sensor.

15. Reset the engine idle speed to specs if necessary.

16. Run the engine at 2500 RPM in neutral for 30 seconds and then record the tailpipe CO reading at 2500 RPM.

17. If the CO reading is 1.2% or less move to step 18. If the CO reading is still greater than 1.2%, the carburetor must be replaced at this time. Skip steps 18 through 21 and proceed to Section K.

18. Turn off the engine, disconnect the tachometer and remove the analyzer probe from the tailpipe.

19. Install the concealment plug into the hole to seal access to the idle mixture adjustment screw.

20. Reinstall the air cleaner assembly.

21. Move to Section L.