Centrifugal Governor
WARNING: This page is about a different car, the 1983 Volkswagen Vanagon, 1983 Volkswagen Rabbit, 1983 Volkswagen Quantum, 1983 Volkswagen Pickup, and 1983 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.
The amount of fuel injected is controlled by changing the injection cut-off point according to engine speed and load conditions. The cut-off point is controlled by the position of the metering sleeve around the distributor plunger.
The sleeve normally covers a relief port in the plunger. Uncovering the port stops injection. The sleeve position is determined by a centrifugal governor and accelerator linkage. A large quantity of fuel is supplied during starting, less at idle. Once the engine obtains a predetermined maximum RPM, fuel flow can no longer be increased.