1. Locate the idle adjustment screw. It is usually located on the side of the carburetor, near the throttle linkage.
2. Use a screwdriver to turn the idle screw clockwise to increase the idle speed, or counterclockwise to decrease it.
3. Start the engine and let it warm up to operating temperature.
4. Adjust the idle speed to between 550 and 650 RPM using the idle screw.
5. Turn off the engine and check to make sure that the idle speed is still correct.
If necessary, repeat steps 2-5 until the desired idle speed is achieved.
