Did the motor ever have remote controls? If not, you will need the SRC kit of parts to connect the controls at the motor end:
3A1838801M | SRC KIT;9.9B-18C,25,30 | $188.17 |
Cables are standard Morse type. Measure as per usual: distance from control to transom, add distance from rt corner of transom to motor, add 3 feet for a steering "loop" so the motor can turn without the cables binding.
If it is electric srtart (is there an electric starter motor?) then you will want an RC box with key switch. Does it have power tilt/trim? If so, your RC box will need that switch as well. If it has remote steering, you need the appropriate box to accommodate that as well.