Caution: Before making any carburetor adjustments, check that spark plug gaps are correct and that all electrical connections and vacuum hoses are securely connected and fully functional. An accurate tachometer and exhaust gas analyzer must be used to perform carburetor adjustments.
Check the idle speed adjustment and the quality of the fuel mixture. Leave the tachometer connected. The idle speed must be adjusted before adjusting the fast idle speed.
Warm up the engine to operating temperature and remove the air filter.
Partially open the throttle valve, then close it until the adjusting screw is positioned on the fourth notch of the fast idle step washer and releases the throttle (see Fig. 4A.30).
Start the engine and, without touching the accelerator pedal, check the idle speed and fast idle speed. If adjustment is required, turn the fast idle speed adjustment screw clockwise to decrease the speed or counterclockwise to increase it.
Turn off the engine, disconnect the tachometer with the fuel mixture quality meter and install the air filter.