Older steering cables had a zerk fitting next to the big nut on the tilt tube. I haven't seen that recently, likely because you could pump grease into the zerk and bind up the steering cable.
The only maintenance required is to extend the steering rod to the max, wipe off the old grease (use turpentine if necessary), and regrease it. Quicksilver makes Special Lube 101, which is designed for steering rods, but any grease is better than none!
Clean and regrease once/season, before layup, and you should not have an issue. This goes for sterndrives as well as OBs.
