Automatic start — general description (VW Beetle)

When you press the accelerator pedal before starting a cold engine, the throttle lever is pulled down by the accelerator rod; at the same time the throttle valve opens. At the same time, the air damper in the carburetor is released.

The air damper closes with the force developed by the bimetallic spring. As a result, during starting and warming up, a rich fuel-air mixture enters the engine. As the bimetallic spring in the ceramic housing of the automatic ignition unit heats up electrically, the choke valve opens after 2-3 minutes. Simultaneously, the stepped disc rotates by the bimetallic spring rod until the throttle lever stop screw begins to rest against the lower recess of the stepped disc after releasing the throttle. At this point, the engine runs at normal idle speed.

[The original article is available at: VWmanual.ru]