Yesterday i was out on my ski and got into some very very shallow water pulling up to the dock not realizing tide was down. I immediatly shut it down and pushed it out to deeper water. The bottom was not sand but pure mud. After i got going i realized my speedo was not working, gauge is working reading 0 but will not register any speed. I ran around for a couple hours and it worked on and off. Any ideas what my problem could be other than being a dumba$$ and not paying attention to the tide