Re: Lower romoval on 1980 115 johnson
I'm not familiar with your particular motor, but there are generally two places that shift rods are disconnected. One is inside the motor cover, where the shift rod is connected to the shift cable or rod coming in from the front of the motor ... or, inside the exhaust housing, generally accessible from the opening you've already got, or behind a plate or screen on the side of the exhaust housing.
Someone else may be able to give specific instructions for your motor. I assume you must not have a service manual?