To measure the engine crankshaft speed at idle, it is necessary to use a tachometer. The connection diagram varies among different manufacturers, so it is necessary to follow the instructions given in the operating instructions for the specific tachometer.
Before adjusting the engine idle speed, first properly adjust the valve clearances, ignition system (advance angle, spark plugs) should work fine.
Warm up the engine to operating temperature and make sure the choke is fully open. Disconnect the radiator fan connector, turn off all non-essential electrical consumers and the air conditioner (if it is installed). On models with automatic transmission, place the selector lever in the "N" position and apply the parking brake.
Figure 2.12. Location of screws for adjusting the quality (1) of the fuel-air mixture and the rotation speed (2) of the engine crankshaft
Start the engine and compare the tachometer reading at idle with that specified in the technical data. Adjustment is made by turning the idle speed adjustment screw of the engine crankshaft (figure 2.12).
Data provided by the website: MazBook.ru
To adjust the quality of the air-fuel mixture in idle mode, an exhaust gas analyzer is required (cO level meter).
Connect it and let the engine idle. Compare the CO content readings in the exhaust gases with the value given in the technical data. Adjustment is made by turning the air-fuel mixture quality adjustment screw (see Figure 2.12).
If the air-fuel mixture adjustment screw is covered by a protective cap, remove the cap to access the screw.
If the idle air-fuel mixture is adjusted correctly, recheck the engine idle speed and adjust it if necessary.
Stop the engine, disconnect the gas analyzer and connect the connector to the radiator fan.