I have a 1991 Nitro with a 150 Evinrude the steering is very stiff. I have greased the turning rods with not much if any improvement. Now at high speeds it pulls to the right and turns fairly easily right bu it's gorilla steering to the left and I have to hold it to keep it from pulling right. Any ideas.

Get new steering cables... very typical of old cables

or pull the insides and clean the sleeves out, you probably have gunk built up in them and they are binding on it. if you take this route, pull the cables, get some liquid wd40 (in a pour can) and with a funnel pour some in the sleeves, let it sit overnight or longer, drain into a bucket then blow out with air, repeat then reassemble. it is usually easier to just replace the cables.

New cables or go hydraulic

What insides are you talking bout. Im having same problems

Try adjusting torque tab first--especially if it is pulling right. Check owners manual, but think the torque tab would have to be turned clockwise (in the direction of the pulling) to correct a right pull. Good luck!

New cables Mine did that on both old Rangers I used to have got new cables fixed problem.

if the system is old might as well just change the whole assembly and not just the cable. NFB system runs around 180 and might take 1-2 hours to change depending on how tight the turn is at the motor end. I did this a month ago and luckily didnt have to remove the motor to run the cable. Hardest thing about the task is taking off steering wheel.