Re: 82 115 HP Merc Lower Unit banging when in forward gear
The bad news is that the LUs are difficult and expensive to rebuild. First check it for proper adjustment. Remove the throttle cable and shift cable barrel nut from the clamp. Move the throttle handle to make sure it is in neutral. Move the shift slide to make sure the motor is in neutral. Now abjust the barrel nut to just fit the clamp. Hopfully it needs some adjustment.
If that doesn't work, keep your eyes open for a used LU.