I had an old Minn Kota 765MX and it ate up foot pedals like you would not believe. It was an older version than yours even! I measured the resistance of the slider potentiometer and picked up a rotary potentiometer of the same resistance.I mounted everything in a water tight box. I turned it into a hand controlled unit with a piece of aluminum conduit as a handle that I could control with my knee once I dialed in the speed I wanted. I also had a switch to turn it on constant and a momentary push button in the end of the handle. It worked great and I used it like this for many years. The motor itself was good, just the pedals were built too flimsy.
I used to have the wiring diagram for what I did with all the coloured wires identified, but it was like over 20 years ago.