I thought I remembered there was a reason I removed the trim tab when I
take off my lower unit. I only do the water pump every couple years so
the details get fuzzy. It comes back to me when I get out the tools
:-)

Drilling a big hole through the the front half of the tab might allow
you to get at that bolt and then drop the lower unit. Or might be able
to chisel the front half of the tab off.

Ernest Scribbler wrote:
"Ernest Scribbler" wrote
It stays with the LU, like so: http://www.mercstuff.com/images/wp08.jpg

Come to think of it, though, there's a bolt in the trim tab cavity that goes
up into the upper, so you still need to get the tab out of your way. If it
comes down to drilling, it might be easier to drill/grind/burrow through the
tab than the bolt.