That is a Mercury Ride Guide steering set up.
Have the same one in the Southwind.
I may have what you need but need to scope it out.
If you even think you have a cable issue, swap it for a newer set up. You'll be glad you did. Those old Ride Guide systems were pretty good, but if the center bolt was ever left loose they get really funky and tear up the plastic bearings, then they are all floppy.
I'll check later to see what I have for that. I think the last boat I parted out had a Quicksilver system (same chit).
GT