Automotive Carburetion Made Easy



			IMPORTANCE OF ADJUSTMENTS Continued The fast idle setting is made to determine the proper engine RPM when the engine is cold and the choke valve is partially closed. If possible, this setting should always be checked on the engine. If improperly ad-justed, it can cause stalling or loading up during engine warm-up. IT MUST BE CORRECT.

	The unloader adjustment is made to prevent loading up on a wide open throttle accelera-tion during the warm-up period. This is ac-complished by the throttle movement me-chanically forcing the choke valve partially open to admit more air. If improperly ad-justed, excessive richness and loading may result. IT MUST BE CORRECT.

			The atmospheric idle vent adjustment on GM 4-Jet models is made to facilitate smooth idling, especially when hot. With the throttle valves in the slow idle position, this vent valve is held open to allow fuel vapors to rise and pass off. It must close immediately as the throttle valves are opened to prevent atmospheric venting. If improp-erly adjusted it may cause rough idling when hot or poor mileage in the economy range. IT MUST BE CORRECT.

	The secondary lock out adjustment on GM 4-Jet models prevents the secondary throttle valves from opening during engine warm-up. It holds secondary valves closed, allowing primary valves to open fully against tension of override spring. If im-properly adjusted, it may cause flat accelera-tion during warm-up or a bind in automatic choke action. IT MUST BE CORRECT.

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