How to hook up the speedometer

[MStrick9]

Hey Guys. I have a 1988 Johnson 150HP outboard on a 19' Bass boat. When I purchased it the fuel guage and speedometer were not connected. Can someone help me identify what the speedometer wire coming from the outboard would look like and how to reconnect it as well as the fuel guage. I am slightly concerned about hooking up electrical components to a large fuel tank.

 

[wilde1j]

Re: How to hook up the speedometer

No wire for the speedo, just a tubing connection from the sensor to the gauge. Fuel gauge is usually a two wire connection from the sender in the tank to the gauge. If the gauges are internally illuminated, there will be a switched +12V for the lamp and in the case of the speedo, a ground as well.

 

[ezeke]

Re: How to hook up the speedometer

The wire for the fuel tank should be pink, and is not connected to or through the motor. If you want it to be off with the ignition switch, take the positive feed from the ignition switch 'A' post (purple wire) to the gauge.

Be careful with your connection - the sender is a 12 volt variable resistance unit hanging in a tank of gasoline.

 

[MStrick9]

Re: How to hook up the speedometer

Thanks ezeke, that was what I was afraid of. I see a red and black wire coming off the guage at the fuel tank. How do I ensure that I don't blow this thing up. I would like to hook it up to the ignition switch.

 

[MStrick9]

Re: How to hook up the speedometer

Jim,

You mentioned a tube coming from the motor that needs to be hooked up to the speedo. What does it look like. Can you describe it for me or give me a diagram?

 

[wilde1j]

Re: How to hook up the speedometer

You motor's lower unit may have an integral pitot tube sensor, whjch would just be a forward facing hole, with tubing (~ 1/4" OD) running up to the powerhead area, then forward with the wire bundle to the control unit or dash area. The tubing end just plugs into the back of the speedometer. BTW, the speedometer needs no electric to work ... it's only for internal illumination, if the gauge has a lamp.

If your motor is not so equipped, your boat may have a pitot installed on the bottom of the transom with tubing going up into the back of the boat. That tube continues forward to the speedo, and again just plugs into the back.

If your boat has neither, you can buy a pickup from any boating supply for very little cost ... Walmart may even have it.

 

[MStrick9]

Re: How to hook up the speedometer

Good stuff Jim. Did you happen to read my reply about the fuel guage above. I am a little nervous about blowing up this thing if I hook it to the battery. Can you tell me more about that?

 

[wilde1j]

Re: How to hook up the speedometer

Typical for most fuel gauges:

STEP 1: Connect the first wire (pink) between the top terminal screw of the Fuel Tank Sender and the ?S? post on the back of the fuel gauge.

STEP 2: Connect the second wire (typically black) from the terminal post marked ?G? on the gauge to the ?GND? post on the back of the Tachometer or to a common grounding terminal behind the dash panel.

STEP 3: Connect a third wire (purple from ignition sw) from the terminal post of the gauge marked ?I? to the ?BAT? post of the Tachometer or other instrument with a purple lead connected. This connection should become ?HOT? when the key is turned ?ON?.

Labelling of gauge connections not always the same, ie #1 might be "sender", #2 might be "GND","-", etc., #3 might be "+", "POS", etc.

Send me a PM w/ your email and I can send you a Teleflex pdf that shows their connections.

 

[Silvertip]

Re: How to hook up the speedometer

Here is a diagram of the fuel gauge system. Pretty straight forward. For +12 volts and ground at the gauge you can simply connect those two wires to the same terminals on any other gauge.

 

[MStrick9]

Re: How to hook up the speedometer

Perfect Thanks to you all. This is a great forum.