1995 Four Winns 190 Horizon speedometer stopped working

[rkkr51]

This is my first motor boat having been a sailor for years. When I put the boat in the water a few weeks ago the speedometer was working. After a week in the water the battery died so i replaced it. After that the speedometer stopped working. I'm not sure if there is a sensor that is bad. The analogue trim gauge stopped working at the same time. Any ideas?

 

[Silvertip]

Speedometers are pitot driven so there is no sender but there is a pitot built into the lower unit on the outdrive. The hole is probably plugged by debris. Speeds are mechanical - not electronic. The trim gauge is electrical and it's failure was coincidental and not related to the speed.