Mercury - Gen I Throttle and Shift Cable 20 Foot Mechanical Engine Control 8M0082493. The Mercury Gen I Throttle and Shift Cable (20 Foot / 6.1 m) is designed for boats using traditional Mercury Gen I mechanical control systems. This cable connects the control box to the engine to deliver direct, responsive throttle and shift movement without electronic involvement. The 20-foot length is ideal for wide-beam boats, deeper hulls, and long helm-to-engine routing where additional distance helps main