Definitely need to disconnect the lower and upper shift rod. Additionally, make sure you dismount the exhaust snout and there should be another bolt underneath it that needs to be removed also.
Might mean the trim tab, under the antiventilation plate, behind the prop.
MARK THE ANGLE the trim tab is set for before taking it off to get to the bolt under it.
(You probably already got that off if the lower unit is dropped 1/2 inch)
Because you already dropped it partway with the shift linkage connected you will have issues putting it back together.
Once its apart, hand move the shift linkage to find neutral.
Measure the shift rod from where it enters the gearcase to top. Write this down. You need +/- 1/32 inch or 1mm accuracy. (no those are not equal)
When you put it back together you need the upper unit gear linkages set for neutral. the shaft has to be screwed back in to the correct amount. (even if you don't take it out, they tend to twist 3 or 4 turns while you change impeller)
