Automatic engine start system (VW Transporter T3)

When you press the gas pedal before starting a cold engine, the throttle lever is pulled down by the gas cable, opening the throttle valve. At the same time, the air valve axis is loaded. Under the force of the bimetallic spring, the air valve in the carburetor closes. Due to this, an enriched air-fuel mixture is prepared during the engine warm-up process.

With the electrically heated bimetallic spring warming up for 2-3 minutes, the air damper opens, and at the same time the stepped washer is turned so much that the throttle stop screw enters the lower groove of the stepped washer. From this moment on, the engine starts to run at normal idle speed.

(The text is copied from this portal: «vwmanual»)