Re: Removing lower unit of 1965 6HP Johnson
Use the shifter to enlarge the area by putting it in forward position, thus raisng the shift rod from the gearcase. Then with the bolts out, moving the lever to reverse will give you more space.
You won't have room for much but a 1/8 drive and socket or a screwdriver should work.
You have to completely remove the screw. They are special, so don't lose it.