Airgiude leaking water

Before winterizing last fall, the left speedo on my '89 SN was leaking water from behind the dash. It was pouring in so rapidly at high speed it was filling up with water inside the glass. I tried to dry it out the best I could before putting the boat into storage. As I suspected, this spring the speedo is not working at all, but there is also no more leaking. I've inspected around the pitot and the tubing going into the hull and there does not appear to any cracking or leaks. What is the best method for tracking down the problem or replacing the speedo and tubing? Any help would be appreciated. Thanks.