Speedometer question.

[mogfisher]

Hello. I recently aquired a boat that needs a bit of TLC. Mostly electrical which is fine for me as I'm good at 12volt. How does the speedo work? This is an 89 Bass Tracker 1800TF fiberglass with a mercury 150 xr4. In a pile of parts in the bottom of the boat I found 2 fishfinders (Bottom Line, old as the boat) and a little paddle wheel. The mounts for the paddle wheel are broken but I don't see anywhere under the boat where it would have been attached anyway. Must it have been? Also, the plugs on the end of the cable to the paddle wheel plug into one of the fish finders. Well, one of them does. Not sure about the other. What's the deal? Do the original fish finders send signal to the speedo? that would seem odd to me. Thanks!

Adam

 

[QC]

Re: Speedometer question.

The paddle wheel is probably for the fishfinder alone.

Most in dash speedos are driven by air pressure from a tube that originates either at the motor or from a Pitot tube that hangs in the water.

Take a look at this thread. Ignore the GPS stuff and it should help you with your in dash question.

 

[Silvertip]

Re: Speedometer question.

Paddle wheel speedometer senders don't attach to the bottom of the boat. They attach at the stern of the boat and depending on type, may be attached to the locator transducer mount or they may be installed separately. The speed readout is on the locator not the analog gauge. A separate pitot (either on the boat or integral with the engine) is required.

 

[mogfisher]

Re: Speedometer question.

Interesting. I sure wish I could get an manual for the boat. I've ordered the manual for my motor, but it would be nice if I could find a manual that explains how to operate all the switches and maybe a wiring diagram for all the electronics. Other than asking here or just wingin it is there a way to figure out all the wires on a given boat? Thanks for the help.

Adam

 

[Silvertip]

Re: Speedometer question.

Don't bother holding your breath looking for a Boat Service Manual. Most manufacturers don't publish one. Wiring very generic and if you can't figure out what the switches do, just ask. Or -- turn it on and see what happens.