Temp Gauge not working
 

I have a 1986 170 HP I/O. Had a very small fire (the voltage regulator fried) which burned some of the surrounding wires. Made all the repairs, including installing a new alternator kit and only thing left is that the temp gauge is blank. From what I've read the brown wire goes to the temperature sending unit.

My question: Per the attached picture (port side of engine), do I just need to run wire from the brown wire shown and up to the sensor on the same side of the engine? I don't want to short anything out but need to know my temp. Thoughts anyone?

UPDATE: New temp gauge is working - but temp is hot. Water comes in to heat exchanger fine, but gets hot fairly quick. Any ideas what this could be? Is there another water pump to circulate the coolant? I checked the exchanger and it looks very clean. Where is the water pump located which circulates the coolant? Any ideas are welcome.

I COULD be wrong..so don't take this as gospel.. but....

On my old boat, which had an I/O setup there were 2 water pumps.. one in the lower unit which pumped raw water to the heat exchanger, and a second on the engine, which circulated fresh water from the heat exchanger through the engine. That pump was located on a bracket on the front of the engine and was driven by a v-belt running off the crankshaft dampener pulley.

Not sure if your set-up is the same, but to me it would seem like the logical place to start looking. :head:

PS...Follow the hoses from the heat exchanger to your engine.. one of them probably goes to the pump.

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Unfortunately the new temp sensor works just fine (checked with laser thermometer). My boat didn't even have a belt until I replaced the faulty voltage regulator with the new alternator kit.

So, I checked the outdrive pump works well (disconnected hose and raw water pumps in just fine). I hear the internal coolant pumps on these 170's can fail. So my question is what type of effort and money would it take to fix - if this is indeed the issue? Any insight here is appreciated.