Altitude Compensator: Description and Operation

Fig.158 - Air Jet Controller:

The air jet controller, Fig. 158, is an atmospheric pressure sensing device which controls the amount of air flow into the slow air jet and main air jet of the auxiliary carburetor, and the second slow air jet of the main carburetor. As the ambient pressure is reduced by increasing altitude the bellows expands to open the air jets, increasing air flow to maintain optimum air/fuel ratio.