Tempature gauge hook up question

[iwaterdave]

Had really good advice so for so here is another. I have this 86' 125 Force outboard and really don't want to rely on the alarm buzzer. Its probably just as old as the boat. Found this gauge in a box of parts from the guy I got the boat from. Hoping its compatible. I tried to hook up a ground wire, the purple wire from the engine and a power that runs the back light. No change in the gauge. Am I missing something in the hookup? It has 3 poles on the back and a wire harness for all 3. What else am I hooking up? One pole has a "S", another says "GND", last one has an "I" on it.

 

[jerryjerry05]

For you guys who don't trust the buzzer on the overheating system.
​Install a horn from any car.
Just make it a LOUD one.

 

[jerryjerry05]

G=ground
​S= sender
I=ignition

Hook it up , key on, ground out the orange lead on the block.
Should make the meter peg.
It's basically the same as a as gauge or volt meter

 

[iwaterdave]

No Title

G=ground
​S= sender
I=ignition

Hook it up , key on, ground out the orange lead on the block.
Should make the meter peg.
It's basically the same as a as gauge or volt meter

So I looked at what I had this morning and am confused. ​The orange wire is the wire for temperature, but the wire harness has a purple wire for the sender wire. I followed the purple wire back and it goes to the black box next to the starter and that box is grounded to the starter and has wires going to the stator. Would the purple wire be my ground then? Lastly can the ignition wire be any power wire when the ignition is on?
Also will this motor show actual temperature or is it just overheat or not overheat?

 

[jerryjerry05]

You can see the orange lead hook to the orange in the harness, pic#2
The orange lead on the motor should hook to an orange lead in the harness.
​The purple should be a hot lead.
You must have had someone hook it up differently.
The sender should make the buzzer sound off.
The gauge probably won't read from that sender. It probably will if the motor gets hot but only if it gets hot enough to make the buzzer work.
Look in the box of parts and see if there might be another sender.

The sender and buzzer sounds at 130-150d(I think) that's before any damage can be done.

​Pay no attention to the colors in the plug.
follow the I S G

 

[iwaterdave]

You can see the orange lead hook to the orange in the harness, pic#2
The orange lead on the motor should hook to an orange lead in the harness.
​The purple should be a hot lead.
You must have had someone hook it up differently.
The sender should make the buzzer sound off.
The gauge probably won't read from that sender. It probably will if the motor gets hot but only if it gets hot enough to make the buzzer work.
Look in the box of parts and see if there might be another sender.

The sender and buzzer sounds at 130-150d(I think) that's before any damage can be done.

​Pay no attention to the colors in the plug.
follow the I S G

​Any way to test the sender?

 

[tommarvin]

Don't you need to install a screw in temp sender at the top of head,where you remove the stainless steel plug ,which won't come out on our 125hp head,hitting it hard with a three pound sledge, with an impact screw driver, and screw in the temp sender, for the temp gauge to work?

 

[iwaterdave]

Don't you need to install a screw in temp sender at the top of head,where you remove the stainless steel plug ,which won't come out on our 125hp head,hitting it hard with a three pound sledge, with an impact screw driver, and screw in the temp sender, for the temp gauge to work?

​My temp gauge sending is on the center of the head not the top.

 

[tommarvin]

Yes, we to have the orange wire going to the sender for the overheat buzzer.
Can we hookup a new digital temp gauge to the overheat sender going to the buzzer to?
Or do we have to install another screw in temp sender for new digital temp gauge?
We bought a new temp guage and it came with it's own temp sender to install at top of the block in a plug?

 

[iwaterdave]

Yes, we to have the orange wire going to the sender for the overheat buzzer.
Can we hookup a new digital temp gauge to the overheat sender going to the buzzer to?
Or do we have to install another screw in temp sender for new digital temp gauge?
We bought a new temp guage and it came with it's own temp sender to install at top of the block in a plug?

Oh, I don't know

​

 

[Nordin]

The gauge need it?s own sender to work properly. If you hook it up to the factory temp sensor (switch) the one with orange wire, it will go from showing zero to showing top of the range.
The factory temp sensor is a sensor it works like a switch (off and on) at a specified temperature value
It will show zero when the temp is lower than the specified temp for the sensor and top of the range when over specified temp.


The gauge needs a sender and it is usually a NTC resistor (negative temperature coefficient) and that means that the resistance will reduce when the temperture increases.
That will allow the voltage to reduce over the sender and increases to the gauge and the gaugeneedle move up the range.

Wire the gauge like this:
G = ground
I = hot when igition ON
S = sender (NTC resistor)

 

[jerryjerry05]

You can test your sender by dropping it in hot water.
​Analog meter: Ohms take reading while cold then again after it's hot.