Ok. I will do my best to explain.

Have you undone the cable coupler nut  that attaches the cable to the motor?  If no, undo this nut. Cable should pull out. If it seized in the motor tube give the end of the steering ram, end on your pics you posted a wack with a hammer to free and hopefully then you can pull whole cable out. Once cables out give motor tube a good clean with dregreaser.

If you cant turn the steering wheel once cables out of motor tube your steering ccables seized and needs replacing.(recommend)

Plenty of info on youtube on all this.

One big mistake people do is the use of grease in the tube the cable runs through motor. Using the wrong grease and it will dry hard. 

Best lube to use is a product called moly lube. Lithium white grease that doesn't out.

Hope this helps.

 Exact same thing happened to my traily, was too seized to even get out and ended up having to remove the outboard and replace the tilt tube and cable. Not a hard job, if you have access to an engine crane. 

Thanks for the good advise all is good now, I was afraid to use the hammer until I read your post, cheers