Not exactly an “apples to apples” comparison but I suspect it’s close enough. I have a 92, 7.4L OMC and just made this adjustment 3 days ago. The manual is crystal clear that you should not attempt to shift UNLESS THE MOTOR IS RUNNING. I did this in my driveway using muffs. I had the outdrive off to replace my gimbal bearing and I replaced my shift cable at the same time. I had the opposite problem, I could shift into forward but had no reverse.
Solution - loosen the bolt, dial the black adjustment screw (I turned mine 4 times 360 degrees) tighten the bolt back up. Took 2 mins. Works as advertised.