Rubber hose on outboard lower unit
 

I just purchased a new to me boat yesterday. It is a 1992 Sea Ray with a 175 Mercury 2 stroke. Both boat and motor are in excellent shape. There is a small black rubber hose hanging out of the front of the lower unit. I have read on the forum that it is probably part of the speedometer. If so, I have no idea what it is supposed to connect to. Photos are attached. I also want to confirm that is all it is before I take it out on the lake this weekend. Can anyone please advise.