High Altitude Compensation System: Operation

Altitude compensator mixes air into gasoline when it enters idle/low speed circuit and main metering circuit passages in carburetor. Metering of air bled into carburetor is accomplished by use of an aneroid valve bellows, which simultaneously moves 3 spring-loaded needle valves.

As altitude increases, atmospheric pressure will exert less force on bellows, causing bellows to expand and mechanically open needle valves. Fresh filtered air is supplied to needle valves from inboard side of air cleaner element.

One-way check valves (if equipped) are located in series in the primary and secondary main metering air lines near carburetor. These check valves will prevent any liquid fuel from entering the altitude compensator housing. Altitude compensator is attached to front of heater air intake duct. Fresh air inlet to compensator is connected at bottom of air cleaner housing.