Re: Removing tilt trim and 115 Mercury outboard for a newbee.
Gerry is correct. That gearcase is from a newer motor, likely mid 80s or so. It is probably completely compatable with your motor, but has the speedo pitot built into it. That black hose should go to a speedometer gauge on the dashboard. Picture 2 appears to show a splice, where you can disconnect it. The two other cables should be for throttle and shift functions.
Gerry is correct. That gearcase is from a newer motor, likely mid 80s or so. It is probably completely compatable with your motor, but has the speedo pitot built into it. That black hose should go to a speedometer gauge on the dashboard. Picture 2 appears to show a splice, where you can disconnect it. The two other cables should be for throttle and shift functions.