Mercury – Gen I Throttle and Shift Cable 21 Foot | Mechanical Engine Control | 8M0085962Mercury Gen I Throttle and Shift Cable 21 Foot Mechanical Engine Control The Mercury Gen I Throttle and Shift Cable is designed for boats using Mercury mechanical control systems that rely on a direct, hands on connection between the control box and the engine. Built for legacy Mercury Gen I control interfaces, it delivers a familiar, predictable helm feel without electronic involvement. The 21 foot (6. 4 meter) length supports longer console to