Mercury - Gen I Throttle and Shift Cable 27 Foot Mechanical Engine Control 8M0082500. The Mercury Gen I Throttle and Shift Cable (27 Foot / 8.2 m) is designed for boats using traditional Mercury Gen I mechanical control systems that require extended routing distance. This cable connects the control box to the engine to deliver direct, responsive throttle and shift movement without electronic involvement. The 27-foot length is ideal for wide-beam boats, deep hulls, and long helm-to-engine layouts