Mercury 20HP Stuck Lower Unit

Trying to change the impeller on my `89 2 stroke 20HP mercury outboard. I`ve removed all the securing bolts and nuts but the lower unit won`t budge.
Anyone any ideas on what is the cause and how to remedy it?

Did you disconnect the shifting rod from the engine to the lower transmission?

Should be like a bar running from under the engine through the leg to the transmission at the bottom, normally can be split when removing the lower unit for impeller change, held in with a roll-pin or small bolt and nut....

Hope this helps.

Spot on Bracken.. The gear leaver needs to be split. The might be a rubber grommet in the leg to give you access. You may have to go into gear to access the bolt.