Re: how do I get reverse back?
Remove the lower unit. Shift the motor to Neutral.
Cushion a pair of pliers or Vise Grips with tape or suitable shop rag (to avoid marring the shift shaft splines) and rotate the lower unit's shift shaft until the lower unit is shifted to neutral. If you turn the prop a bit as you're shifting the lower unit, it'll be most evident what gear you're in and when you hit Neutral. There's a very limited range of travel in the shift shaft to induce shifting action, so you can't really get too lost. Turn it one way or the other to get to Neutral.
With both lower unit and motor shifted to Neutral, reassemble. You'll need to rotate the flywheel in order to engage driveshaft with crankshaft, as you're reinstalling. Be sure you've pulled both spark plug wires off the spark plugs before doing so.
HTH.........ed
