Air Injection Pump: Description and Operation

Fig. 2 Air injection pump with integral centrifugal air filter and pressure relief valve:

The belt driven air pump, Fig. 2, is mounted on the front of the engine. Intake air passes through a centrifugal fan at the front of the pump, where foreign materials are separated from the air by a centrifugal force. Air is delivered to the air injection manifold and tube assembly by a rubber hose through the [1][2]air switching valve mounted on the rear of the pump.