I just bought a used minn kota edge 70.  OMG new plug and receptacle and wire are expensive. Same total cost that I paid for trolling motor. I can't tell what wiring awg , no markings, that it has now for an OMC 24 volt trolling motor in the boat. It's got a 3 prong, blk, red and orange. Can I use the existing blk and red wires and just not connect the orange? I know I'll have to change wiring at the bow plate. I was hoping to just cut the plug off the omc and attach it to the minn kota. Of course I would track the red and black back and install a 50 amp breaker per manufacturer. They also recomment 6 awg wire. 

 

DC is 2 wires, AC 3 wires. Your OMC may be a 12/24V motor with a switch at the foot peddle and the reason for 3 DC wires.

Tom