Your best bet is to just replace the whole system. You can get a complete rotary set up from here http://www.lowcostboatingstore.com/...e-9-ft-to-20-ft-with-STEERING-WHEEL_p_19.html for $111 and it even comes with a new wheel. This assumes your motor has a tilt tube to attach the steering rod too. Most '70s or newer motors have them. Here's an example:
I put cable pulley back on my 66 nassau, easy and inexpensive. Works great. I refinished my steering wheel too, with JB weld and Rustoleum Plastic primer and paint. it turned out great!
