I picked up a rope around the outdrive after cutting it, free I find I can no longer turn left. With the wheel turned all the way to the left, the outdrive is only pointing straight.
Oh, boy------I had something similar happen several years ago. It sounds like the steering tube has slipped in the bracket that is screwed into the transom area. I don't know which model of Duffy boat you have, but take a look at where the steering cable connects to the motor. There is a tube that is clamped to a bracket (usually, the bracket is white in color) to see if it has slipped out of position. To fix it, center your steering wheel, then loosen the four bolts that hold the bracket to the silver steering tube and slide the steering tube until the rudder is also centered. Then, tighten the four bolts so that the tube cannot slip in the bracket.
If this is the problem, it is a simple fix. Good luck, and please let us know the outcome.