1985 Mercury 50HP, I am trying to drop the lower unit to get at the impeller. I've removed what all the relevent nuts and bolts. Five total. One at the trim tab, one inside the trip tab cavity, a nut just forward of the tab, and a nut on each side. After some gentle aggression she just barely drops down 1/3" maybe - i am also not able to completely remove the 5/8" nuts from the bolts as it won't drop far enugh to let me do that, but there is about 1/2" of bolt showing below the bottom of the nut which is as far up as it will go.
Am I missing something?
I did not remove the prop as i read it wasn't necessary.

this is what the manual says:
Check again to be sure the lower unit is in FORWARD gear.
Scribe a trim tab reference mark on the anti-cavitation plate. This mark will ensure the trim tab will be installed back at the same angle.
On many models retainers for the trim-tab zinc require a 12-point socket (often 7/16" in size) for removal.
Remove the plastic cap from the rear edge of the exhaust housing. Insert the proper size wrench into the hole and remove the trim tab adjusting bolt, and then the trim tab.
After removing the trim tab, remove the nut from the recess.
Remove the 5/8 in. nut from the bottom middle of the anti-cavitation plate.
Loosen the 5/8 in. nut located on each side of the exhaust housing. DO NOT attempt to remove these two nuts at this time.
Separate the lower unit from the exhaust housing as far as the nuts and studs will permit. Hold the lower units from falling and at the same time remove the two nuts.
Remove the lower unit from the intermediate housing.
Am I missing something?
I did not remove the prop as i read it wasn't necessary.
this is what the manual says:
Check again to be sure the lower unit is in FORWARD gear.
Scribe a trim tab reference mark on the anti-cavitation plate. This mark will ensure the trim tab will be installed back at the same angle.
On many models retainers for the trim-tab zinc require a 12-point socket (often 7/16" in size) for removal.
Remove the plastic cap from the rear edge of the exhaust housing. Insert the proper size wrench into the hole and remove the trim tab adjusting bolt, and then the trim tab.
After removing the trim tab, remove the nut from the recess.
Remove the 5/8 in. nut from the bottom middle of the anti-cavitation plate.
Loosen the 5/8 in. nut located on each side of the exhaust housing. DO NOT attempt to remove these two nuts at this time.
Separate the lower unit from the exhaust housing as far as the nuts and studs will permit. Hold the lower units from falling and at the same time remove the two nuts.
Remove the lower unit from the intermediate housing.