Hello, ’67 Beetle community. We’ve been receiving a lot of emails about this topic. This is an older article from our good friend, Jay Salser. Give it a read if you have not already. As always, a huge thank you to Jay for all he does for 1967beetle.com.
If your Deluxe 1967 Beetle has a 30 Pict-1, VW 105-1 carburetor, you will have noticed, as in photograph #1, a little “canister” protruding from the passenger’s side, right at the generator. If you have not noticed this “canister” maybe yours has been replaced by a simple brass jet.
Volkswagen called this “canister” the Pilot Jet Valve. Today, it is called variously, although most people call it the Cut-off Valve or Idle Cut-off Valve.
Volkswagen carburetors have a brass jet which is called the Idle Jet. When the car is not in motion, for instance, the accelerator pedal is not being pushed. But we want the engine to continue to run so that when we are ready to start moving, the engine will be ready for that operation. The idle drilling draws gas, using vacuum, to keep the carburetor feeding some gasoline/air mixture to the engine—enough to keep it running at low rpms for us. The brass jet usually is marked g55 for many Beetle carburetors over the years.
The cars of yester-year sometimes had a tendency to “diesel”—that is, to continue running after the key was turned off. The Volkswagen was no different. Probably most of us have experienced this problem at one time or another. A VW mechanic tells me that dieseling could be due to a leaky gasket or a high fuel level or pressure. Such conditions would cause fuel to continue to feed through the idle port and cause the engine to run—usually very jerkily—ka-Chug-a–ka-Chug-a….