Re: shift lever removal on 1973 Mercruiser 165
You have to remove the neutral (black) knob in the center of the chrome shifter handle, turn the knob counter clockwise and it,,, should come out (if it's not corroded in place). With that knob removed, and the allan screw removed, the shifter handle wiggles off.
To get to the shift cables, you need to dismount the remote control box and then take it apart, basically take the halves apart, 4-6 screws. While you are in there, lube it up with some lithium grease, mine was pretty hideous when I took it apart, grease was all dried out. 40 years will do that.
I had the same shifter on my 73 140HP Mercruiser, still have it in a box of parts, somewhere...