The engine idle speed should be checked (and adjusted, if necessary) with the engine up to operating temperature.
SAFETY FIRST: Protective gloves and eyewear are recommended at this point.
Shift the transmission into neutral, and connect a tachometer.
Turn the idle adjustment screw on the left side on the carburetor to set the idle speed to specification.
(Specification for idle speed is 1,600 to 1,800 rpm)