Checking and adjusting the fast idle speed of Keihin carburetors (when warming up the engine) (Audi 80 B3)

The throttle clearance can be adjusted by adjusting the fast idle speed. The carburetor does not need to be removed for adjustment. The fast idle speed should be checked and adjusted if the engine has dips when throttle is applied or if the engine does not accept the gas well when cold.

The carburetor remains installed.



Warm up the engine. Oil temperature +60°C.

Connect the tachometer with the ignition off.

Check idle speed adjustment.

Check the ignition timing.

Remove the air filter. Plug the vacuum hose of the air heater control (black connector) with a suitable stopper.

Pull the starting (air) damper drive out completely. Damper lever "1" should be in contact with the stop.

Start the engine.

Fully open -arrow A- the air damper on lever "2".

Check the number of revolutions, set the required deviation of the stop lever -arrow B-. See the meaning in the chapter "Repair characteristics".

The number of revolutions is too high: press the lever.

The number of revolutions is too low: release the lever.