Its not a sophisticated system. A standard car power steering pump feeds pressure through an actuator valve to a bi-directional ram. The actuator is connected to the steering wheel via a cable and directs the pressure to one or the other side of the ram as required by the direction. The cable is also connected to the stern drive steering arm so that in the event of a pressure failure some steering is possible.
A brief check around showed that everything looked ok. The fluid level was correct, the steering was moving the stern drive and the actuator was moving left and right.
The diagram below shows the general set-up
A quick google showed that the failure of the steering following a winter lay up is a comparatively common issue and is down to the steering cable (either corroding or the grease hardening up)
As it is a non-serviceable item on the Regal 2250 the easiest step forward is to change it. The only disconcerting aspect for us was that when the old one was disconnected at the actuator end the steering became lovely and loose which was concerning as we felt it should still be stiff if it was the cable. However another quick google showed this to be a common aspect of a bad cable, it feels fine when disconnected at one end.
So we got an engineer to change it. It is a nightmare of a job, the actuator end is hidden behind the engine and the old cable is loomed into the electric loom running down the gunwale. In the end they had to leave the old cable in place with the ends cut off and feed the new one through on its own. For any other Regal 2250 owners who have a rack and pinion set up the cable is a Telflex SSC13417 17ft Rack and Pinion cable (from marinescene.co.uk - thanks guys for the prompt delivery).
The good news is that it is all cured. Its back to flicking the steering with one hand with a super light steering wheel!
