Thread: Speedometer not working

check for a loose hose on your motor, about a 1/8 inch ID hose that has been an issue I have had in the past

If not the hose, check for a small hole on the front face of your lower unit. They get chunks of wood stuck in them and quit working. If the OB is older, you could have a pickup on the transom too, which could have the same issue.

Don't worry about it. Pressure driven speedometers are worthless anyhow. Chances are it's a foreign object in the pitot (small hole in the face of the lower unit). You can take a needle and dig it out or carefully use a small drill bit to insert and turn by hand to back it out. On really tough stuff, you can locate the small tube that runs from the motor to the speedometer and use an air line to blow from the from speedometer back - NOT forward.

Wannabe...

All a speedometer on a boat is good for is to fill in a hole in the dash........they are very inaccurate, don't work half the time, algae grows in the tube and makes it read too slow, debris gets in the pick up hole, etc. Just go by gps and you will be right on.

Originally Posted by "G"

All a speedometer on a boat is good for is to fill in a hole in the dash........they are very inaccurate, don't work half the time, algae grows in the tube and makes it read too slow, debris gets in the pick up hole, etc. Just go by gps and you will be right on.

Yep I agree.

I just installed a new pitot tube and tubing this spring and my dash speedometer still reads 4-7 mph faster than I am actually going. I watch my handheld GPS now.

If you have a pitot, crap tends to build up in the tubing over time and may be hard to pinpoint where the blockage is if it isn't right at the sensor itself. The stuff is pennies per foot and takes all of three minutes to replace.

Thanks for your help guys.