Carburetor Adjustment
With engine at normal operating temperature, adjust idle speed to 800-900 RPM with idle mixture adjusted to give a CO reading of 2±.5% (except 124 Sedan & Wagon) or 3±.5% (124 Sedan & Wagon) using a suitable CO meter and tachometer. Now, check and adjust if necessary, fast idling speed as follows. Depress and hold fast idling pushbutton switch and accelerate engine to approximately 2, 500 RPM. Allow engine to decelerate to fast idling speed and check that speed is 1600±50 RPM. If fast idling speed is not within specifications, adjust fast idling adjusting screw and repeat test. After proper fast idling speed has been obtained, release push-button switch and check that engine slows to normal idle speed within 1-3 seconds.