yoh,
I had exactly the same problem. My second hand Hobie 14 had 2 rudders, one black, one white. The black one was about 2mm thicker than the other and it wouldn't go all the way forward. I sanded back the top of the rudder, rather than the casting, in order to get it to move freely. Both rudders had quite differently drilled holes, neither of which were correct, and both cams were jammed. I filled and redrilled the holes, fixed the cams and now it sails perfectly. It seems to have quite a bit of toe out rather than toe in but I haven't bothered with that yet.