Wiring and Harnesses for Johnson Evinrude Outboards Wiring and Harnesses for your Johnson Evinrude Outboard. Wiring and Harnesses for your Johnson Evinrude Outboard. Universal Boatside Wiring Harness for Johnson/Evinrude (OMC) applications Replaces: 473-9410 Boat-side harness to connect the engine to the control box 20 feet long Round Plug Boat-Side Harness (Red.. $207 . CDI473-9460. Boat Motor Wiring Harnesses, Plugs & Breakers | Great Trolling Motor Wiring Harnesses. Get your new trolling motor up and running with a discount boat motor wiring harness from Great Lakes Skipper. We buy in quantity from top manufacturers like Larson Boats, Teleflex, Marinco, Attwood, and Tracker, then pass the savings on to you.