I pulled my boat out yesterday and while hooking the transom saver up I heard what sounded like water hissing/boiling in the area between where the powerhead attaches to bottom cowling and the lower unit. I have never heard it before or just hadn't noticed it. Any ideas what this could be? is it normal? '99 75hp force. BTW, I checked several times throughout the day and water was peeing. Thanks for your help.