Before making any adjustments, it's important to ensure the carburetor is clean. If it's dirty, clean it thoroughly using a carburetor cleaner and compressed air.
Start the engine and let it warm up to normal operating temperature.
Locate the air mixture adjustment screw. This screw is usually found on the side of the carburetor and is marked with an "A" or "Air."
Turn the air mixture screw counterclockwise until the engine starts to run rough or stall.
Slowly turn the screw clockwise, watching the tachometer, until the engine reaches its highest idle speed.
Let the engine run for a few minutes and recheck the idle speed. If it needs further adjustment, repeat steps 4 and 5.
Once you are satisfied with the idle speed, turn the idle speed screw to adjust the idle to the desired speed (typically between 850 and 950 rpm).
Test drive the car to ensure the carburetor is properly tuned. If you notice any hesitation or rough running, you may need to fine-tune the adjustment.
Note: It's important to make small adjustments when tuning the carburetor and to avoid making any drastic changes. If you are not confident making these adjustments, it's best to consult a qualified mechanic.
