By the time Volkswagens were “in the womb”, carburetion was not a new thing. But the German Engineers tasked with creating a viable engine system for Ferdinand Porsche had to create a system that would work with the air-cooled engines which were being demanded. Bit by bit, the VW carburetors were evolving into what would become a virtually fool-proof unit.
With the advent of the 12 Volt Electrical System, Volkswagen was coming of age. Carburetion would be just one of the areas which would benefit—with better starting possibilities. Let’s look at the Choke Mechanism on the VW 105-1 30 Pict-1 Carburetor.
While there are several parts to the Choke Mechanism, it is relatively simple.
But first—what is meant by “choking the engine”? “Choking” might better be termed “restricting”—because that’s what’s happening. When the Engine is dead cold, the Fuel Mixture must be more “rich” in gasoline with less air. The Engine is “hungry”. So, by restricting (or choking) the in-coming air, this need can be met.
Eventually, in a matter of minutes, the Engine will be running well and will need more air in the Fuel Mixture as it begins to reach operational temperature. It will be “starving” for air. Now the restriction on air can be relaxed—the “choke-hold” can be relaxed and the Carburetor can seek its own Fuel Mixture levels as needed.
We will be examining only the Upper Half of a Carburetor during this discussion of the “processes” or elements which comprise the Choking Mechanism.