50 Yama front p hole tube?

[Big-G]

My 2005 50 hp 2 stroke Yamaha (recently purchased) has a small tube extending from the front of the engine under the cowling to the inside edge of the transom. The tube has been crimped with nylon/plastic ties but the rubber on the tube has dry rotted and leaks what appears to be sea water into the boat. I can cut away the waste and cap the tube with a rubber nipple and clamp but I am reluctant to do so because the flow of water must have a purpose and I don't know what it is. Records show $300.00 plus maintenance on motor in March by Yama dealer and the ticket says nothing of the tube so I'm assuming clamping the tube would not cause problem. Need some feedback from you knowledgeable folks. What is the purpose of the tube and is it safe to cap it?