Altitude COMPENSATOR
The altitude compensator is used for compensation of the air/fuel mixture in response to the elevation by means of supplying additional air to the control air passages.
Below 4000 feet (1200 m) the altitude compensation system does not operate because the air passage in the altitude compensator is automatically closed by the needle valve within the compensator.
Above 4000 feet (1200 m) the bellows in the altitude compensator is expanded and then the lever pushes the needle valve to allow additional air passages to open the control air passages. Air coming into the carburetor through the altitude compensator is metered and supplied to the control passages. This compensates overall air/fuel mixture of the carburetor. See Fig 1 .