speedometer would work once i got on plane but not at low speed but now not at all. what could it be. boat is 1998 sea ray openbow and gauge is original equipment.
Yep, a pitot doesn't work below planing speed, heck my speedo starts at 10 then incriments of 5 till I think 20, then it finally shows incriments of 1.
Wait I was wrong just looked a a picture I posted, it starts at 20! then a hash mark at 25 after 30 it then goes by ones.
Your speedo (not the one you wear on the boat)works by water pressure that is picked up by the pitot mounted to the transom. It forces water through a tube to the back of the gauge. Mine was acting up and I noticed my leg kept getting wet. Turned out to be a pin hole in the tube along side the drivers seat.
While not higly precise, speedometers should give relatively accurate readings from a few mph all the way up. There could be an obstruction in the pitot (they pick up debris from the water all the time), a bad tube, or a bad speedometer. For instance, mine is pretty much right on the money from trolling up to 25 mph, then gets just a little optimistic until it's showing about 3 mph fast at 45.
