Pitot (as far as I know) is only used for a pressure based speedometer. Clean out the pitot pickup hole (run a thumbnail up the leading edge of the lower unit and you should find it): stick a small piece of wire or whatever will fit in there to clean it out. Sand, algae, bits of shell; can be clogged by just about anything.
If that doesn't get it, you can try disconnecting the vinyl tubing at the gauges and blowing compressed air into the pitot pickup.
Luck;
jky
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