Ns50c steering frozen. Help

I have inherited a project boat with a 1992 Nissan ns50c motor on it. It has a steer master mark III cable on it that I can not get unstuck. When disconnected, the motor turns freely. Also, if I unhook the cable from the motor mount, the cable will move freely with turning the steering wheel. When all connected the cable never comes out of the end of the tubing that holds e mototr to the motor mount. Any ideas or poointers would be greatly appreciated!And it I were to buy a replacement cable, would it come with the metal tubing that connects the motor to the motors bracket. Looks like about a 3/4 inch or 1 inch piece of galvanized pipe that is threaded on both ends.Many thanks!

Sounds like you may need a new steering cable. The cable tube (which is also the shaft for the bracket) does not come with the cable.