Throttle Body: Service and Repair

Fig. 10 Mixture adjusting screw pin removal:

The idle mixture adjusting screw is recessed into the throttle body and blocked by a steel pin to prevent tampering. Idle mixture should not be adjusted unless carburetor is overhauled or diagnosis indicates the carburetor as the cause of driveability or emissions related complaints. If idle mixture adjustment is required, remove pin sealing adjusting screw using the following procedure:
1. Remove carburetor from manifold.
2. Drill hole in pin as shown in Fig. 10, using 4 - 4.5 mm drill bit.
3. Drive pin from throttle body using suitable drift, supporting throttle body to prevent breakage.
4. Install carburetor, then adjust idle mixture as required.