I've got a 150 hanging on the back of my boat, and the steering isn't tight at all when I'm idling or coming in to dock. It's a cable system, too. The RPMs are so low I doubt that torque would be the problem. Torque would cause more problems as you gain speed until the RPMs stabilize. Propeller airplanes act the same way on run-up, with torque being a problem until the RPMs stabilize.
One thing to try when you have access the boat (on its trailer) is to crank the steering all the way to the right (I believe) until the steering unit's tie bar (by the outboard) is exposed. On mine the tie bar becomes exposed on the port side of the outboard if I'm standing at the stern looking toward the bow. Take some WD-40 and soak a paper towel, then scrub the tie bar clean of any gunk and grease. Crank the steering all the way to the left to bring the tie bar back inside the steering cylinder. Re-expose the tie bar and repeat the cleaning as necessary.
If it's more than that, I'd have a technician inspect the cables themselves for corrosion. If the cable system itself needs to be replaced, I'd think about switching to a hydraulic system. When mine finally wears out, that's what I intend to do.
