Jet Air Valve System

Fig. 31 - Jet Air System:

Fig. 31a - Jet Air System:

PURPOSE
Jet valves allow additional air into the combustion chamber during idle and light throttle to improve combustion, Figs. 31 & 31A.

OPERATION
Air enters the two jet air intake openings on the primary side of the carburetor. One opening is located above the closed throttle valve, the other is closed off by the throttle valve at idle speed.

When the engine is idling or under light throttle, the pressure difference between the jet air openings in the carburetor and each combustion chamber during the intake stroke is high. This causes a high rate of jet airflow to the combustion chambers.

As the throttle opening is increased, the pressure differential between the combustion chambers and jet air passages is decreases, reducing jet airflow to the combustion chambers.

CONSTRUCTION
The jet valve assembly consists of a jet valve, jet body and spring. This assembly is threaded into the jet piece which is pressed into the cylinder head. The opening in the jet piece should face the spark plug. Jet air passages are provided in the carburetor, intake manifold and cylinder head.