Power steering question

[IanFS]

1988 Mercruiser 4.3 Alpha One
My steering is a little stiff, it's rack and pinion and power steering.
I've disconnected the cable and I can turn the wheel with one finger, so it's not that. I disconnected the tiller and can turn the Stern Drive easily and smoothly.
However with the cable disconnected but the tiller connected to the power steering rod, moving the tiller is stiff ish but smooth but takes a little effort.
I topped up the power steering with fluid and ran the engine, but the steering is not as light as I would expect although it is lighter than without the engine running. I keep the stainless cable ends both well greased with Quicksiler 101, so don't think it's that fouling.
My question is therefore, should the power steering rod move freely in and out without the engine running or is it fairly stiff.

 

[Bondo]

Ayuh,.... Stiff steering is usually caused by corrosion between the end of the cable, where it goes through the aluminum tube of the P/S actuator,....

 

[IanFS]

Thank you so much for your reply Bondo and thats what I thought was the problem.
This is a photo from last year when I replaced the Tiller Clevis pin.
The other day I disconnected it again, like the photo and swung the tiller, easily moving, all good. At the same time I drilled out the Cable clevis pin D to be replaced by an A4 bolt. Tried the steering whilst the cable free from the actuator C (in the photo) and I could turn the wheel with one finger and the tube moved in and out with ease.
Whilst the cable C was disconnected and the tiller was off as well, it was A the tube that goes to the piston which was tight. I could move it but it was a push and pull not an easy movement. So I was wondering if this is normal?
I also understand there is a zerk grease fitting on the valve assembly, would this have any affect on performance?