Adjusting engine idle speed
Adjustment of the engine idle speed is performed on a warmed-up engine (oil temperature not less than 60°C), with the air damper fully open, with the ignition timing correctly set and the clearances in the valve drive mechanism adjusted.
Using a connected tachometer, check the engine crankshaft speed, which should be within 900-1000 rpm.
If necessary, use the mixture quantity adjusting screw (see photo) to achieve the crankshaft rotation speed within the specified limits.
Connect the gas analyzer in accordance with the operating instructions.
Turn off power consumers.
Disconnect the air supply hose from the air filter on the cylinder head cover and close the hose opening with a plug on the air filter side.
Turn the throttle valve and, by turning the shaped sector of the starting device, move the limit screw away from the stop position in the sector.
Remove the plug from the mixture quality (composition) adjustment screw.
Adjust the CO content in the exhaust gases within 1.0-2.0% by turning the adjusting screw (shown by the arrow in the photo); during adjustment, the radiator cooling fan should not rotate.
After adjustment, lock the adjusting screw and close it with a plug.
(The original article is available on the online resource: «AUDImanual.ru»)