Speedometer not working

[brianvolt7]

1990 bayliner cuddy with 120 horse force. Teleflex speedometer.

First time out this season my speedometer worked perfect, now it does not read any speed.

I noticed a rubber tube that goes from the physical unit with the arm to the speedometer. Is this a pressure sensor? I have no idea how they work.

Any thoughts on how to test the components?

 

[Scott Danforth]

Re: Speedometer not working

boat speedos work on a pitot tube system. if that rubber tube is plugged, it wont work. if your hose has a crack in it, you will leak water into the boat.

 

[bobdec]

Re: Speedometer not working

Should be a rubber tube line running the front of the engine to the lower unit. Water hits the end of the tube in the lower unit water inlet holes and creates 'AIR' pressure in the tube that feeds the speedometer. If the line cracks between the inlet and the speedometer water could enter and fill the tube when running, or if the line plugs up no pressure is sent to the speedometer. Open the line and and inspect for water, then blow air into it towards the speedometer with your mouth. The speedometer should move. This line is usually disconnected whenever the lower unit is dropped for impeller changes so it can get messed up with splices, pretty easy to spot.

 

[brianvolt7]

Re: Speedometer not working

I tried blowing into it and it doesnt move the speedo. It seems like it is plugged. can I use a compressor to see if I can blow it out or will this cause damage?

 

[foodfisher]

Re: Speedometer not working

Disconnect at speedo and blow. If the air passes then the speedo is bad or there's a break in the hose.

 

[Scott Danforth]

Re: Speedometer not working

also, dont put more than 25psi into it. the tube is not reinforced.

 

[Cincyrunner]

Re: Speedometer not working

This subject keeps coming up every few weeks. You can actually learn a lot by searching previously posted threads instead of asking the same question over again.

 

[Oshkosh1]

Re: Speedometer not working

I had the same problem...just replaced the pitot and disconnected the tube from the speedo and gave it a quick shot of compressed air. Blew a bunch of goo out the back end(pitot connection). Put a new pitot and viola! Speedo works.

 

[brianvolt7]

Re: Speedometer not working

This subject keeps coming up every few weeks. You can actually learn a lot by searching previously posted threads instead of asking the same question over again.

Thanks Cincyrunner. I always search before I post but I could not find what I was looking for. If you have a recommendation for a thread, please post the link with your comments, that is most helpful. Thanks again!

 

[NYBo]

Re: Speedometer not working

Should be a rubber tube line running the front of the engine to the lower unit.

That only applies to some Mercury Marine products; his boat uses a separate pitot.

 

[brianvolt7]

Re: Speedometer not working

I have discovered that my tube is plugged. Do I need to replace with actual pitot tube or can I use plastic water line from home depot?

 

[LongLine]

Re: Speedometer not working

My speedometer has a sensor mounted on the transom. Sometimes it kicks up a little from the vertical & readings go goofy.

Tom B.
(LongLine)

 

[etracer68]

Re: Speedometer not working

If you want reliable speed, use a GPS. If you dont have a marine GPS, you can use your auto GPS for reliable speed.

 

[JoLin]

Re: Speedometer not working

I have discovered that my tube is plugged. Do I need to replace with actual pitot tube or can I use plastic water line from home depot?

That's a 'nonessential' (as in no safety concerns) hose that isn't exposed to UV. You can use whatever will fit.