Throttle Valve Cable/Linkage: Description and Operation

SERVICE ADJUSTMENT PROCEDURE
The Throttle Valve (TV) Control Linkage System consists of the linkage lever on the carburetor, the transmission control rod assembly, and the external TV control lever on the transmission.

The linkage lever follows the motion of the carburetor throttle lever and has an adjustment screw for limited linkage adjustment capability. The TV control rod transmits motion between the linkage lever on the carburetor and the TV control lever on the transmission. It is adjusted to proper length during initial assembly. The external TV control lever actuates the internal TV control mechanism which regulates the TV control pressure. The external TV control lever motion is controlled by stops internal to the transmission at idle and Wide-Open Throttle (WOT).

The TV control linkage is set to its proper length during initial assembly using the sliding trunnion block at the transmission end of the TV control rod assembly. Under normal circumstances, it should not be necessary to alter this adjustment. Any required adjustment of the TV control linkage can normally be accomplished using the adjustment screw on the linkage lever at the carburetor. Major linkage adjustment (sliding trunnion on rod) may only be required after maintenance involving the removal and/or replacement of the carburetor, TV control rod assembly, or the transmission. Minor linkage adjustment (adjustment screw on linkage lever) may be required after installing a new main control assembly, or after idle speed adjustments greater than 50 rpm, and to correct complaints of poor transmission shift quality.

MINIMUM IDLE STOP
When the linkage is correctly adjusted, the TV control lever on the transmission will be at its internal idle stop position (lever up as far as it will travel) when the carburetor throttle lever is at its minimum idle stop. There will be a light contact force between the throttle lever and end of the linkage lever adjustment screw. Due to flexibility in the linkage system, the linkage lever adjustment screw would have to be backed-out approximately three turns before a gap between the screw and throttle lever could be detected.

At wide-open throttle, the TV control lever on the transmission may or may not be at its wide open stop. The wide-open throttle position must not be used as the reference point in adjusting linkage.