ron,
i have the 115hp on my lx700 which should be similar. from the advice above i agree that a new steering cable is in order. a lot of bad things can happen if you lose steering.
one other thing that may be related is the procedure to put the grease in the steering housing. I read in the merc manual that you should first turn the motor the direction such that the steering piston rod is fully inside the steering housing and then add the grease thru the zerk fitting. otherwise, the steering piston rod will have to work against the grease inside the housing when turning the direction which inserts the piston rod. don't know if this is related to your problem or not, but it is a good thing to be aware of when performing maintenance.
jd