2. Proper carburetor adjustment can only be achieved when the general condition of the engine is good. Valve clearances must be correct and the ignition system must be in good condition and properly adjusted.
3. You will need an independent, accurate tachometer connected to the engine in accordance with the manufacturer's instructions. Check that the air filter is in place, start the engine and let it warm up to normal operating temperature (accompanied by the fan).
4. If according to the law the composition of the mixture cannot be changed, idle speed is regulated by the quantity screw to the value indicated in the Specifications.
5. If you can use both screws, you should adjust the quantity screw first (above the accelerator pump rod - see photo) so as to obtain revolutions 50 rpm higher than the desired value. Remove the cap from the quality screw under the thrust of the accelerator pump, and turn the screw in the desired direction so that at a given throttle position, maximum idle speed is obtained (see photo). Repeat the adjustment with the quantity screw and then the quality screw until the maximum speed obtained with the quality screw exceeds the desired value by 50 rpm. After that, slightly tighten the quality screw so as to reduce idle speed to the desired value.