Adding Temp Gauge to '90 70HP Evinrude - unused hole in head

[Chaparralbob]

I have seen many posts on adding a temp gauge, but haven't seen any reference to an empty threaded hole I see in the head. The engine I have is a 1990 Evinrude 70 HP. Looking from the back of the engine, I see the temperature switch on the top left hand side of the motor. On the right hand side, I see an empty threaded hole. Is this used for a temperature sender that can be used with a gauge?

I am interested in finding the Evinrude or compatible Sierra part number of such a sender, if this is what the hole is intended for.

I found an Evinrude temp gauge on EBay and hope to use it with the proper sender. As part of the kit, I got a temperature sender, but it appears to be too long to go into the unused hole. It came with a bracket to mount the sender using a head bolt. I am very, very reluctant to mess with a head bolt on a 20-year old outboard!

Thanks for any help with this!

 

[Chaparralbob]

Re: Adding Temp Gauge to '90 70HP Evinrude - unused hole in head

For anyone who might have this same question, here is what I found---

The hole in the head is indeed deep enough for the sensor that came in the kit I got. The kit number I have is BRP Evinrude/Johnson #0175411.

The hole was plugged up with debris, and the threads were a little dirty. I cleaned out the hole with with a screwdriver and compressed air, and then cleaned the threads out with some steel wool on the end of a screwdriver. After cleaning, the hole was clearly deep enough for the sensor.

After running the sensor in and out a couple of times, I'm happy with the fit - plenty of threads engaged.

While a water pressure gauge would be nice, this is a good compromise for the price I paid. Maybe the budget will allow another gauge next summer.