Temp sender help! 1986 Mercury, 90hp inline 6

[Imjus4u2nv]

I own the following engine:
MERCURY - ( 90 H.P. (1986 ))
Serial No: 0A968445 Model No: 1090726

After some overheating issues last year (which I believe have been solved by rebuilding the carbs and other repairs), I am attempting to install a temp gauge AND a water pressure gauge.
My engine has pre-tapped hole that goes into the directly into and through the water jacket (I believe by the #4 cylinder).
I bought a pressure kit that fits in this hole and it works - just plug and play.
My issue is with the temp gauge. I bought a temp gauge kit, with flat mount sender from faria. I cant seem to find a place to mount the flat mount sender anywhere. Does anyone know if I can install a flat mount sender somewhere else?
I also got a z-bracket from my mechanic that seems like it will be able to fit better, however I will need to use a 1/8th regular sender and not sure if it will work with my gauge and how I can tell what gauges the sender will work with.

For both options I can just remove a bolt from the water cover jacket cover and mount the sender- however then the sender will be touching the water jacket? Is this what it should be touching?

I know my engine will never give me a perfect or accurate engine temp, but I would like to have the gauge work, and I can always mark the gauge with "normal" running temp and note when it is running hot.

Any help, as always, is greatly appreciated!

 

[Imjus4u2nv]

Re: Temp sender help! 1986 Mercury, 90hp inline 6

Anybody?
I will post some pics later today.

 

[Texasmark]

Re: Temp sender help! 1986 Mercury, 90hp inline 6

Does the sender act as a compression device for the cover as the bolt currently does when installed? If not, your cover gasket may start leaking there where the cover isn't restrained.......where the bolt was removed.....and be careful you don't break the bolt off when removing if you choose that route. Penetrating oil allowed to soak and impact. If you don't have a small impact air/electric wrench, get a conventional wrench and hold in place while striking the end with a hammer in light continuous strokes to create impact forces on the bolt.

Water jacket is alum. Alum is an excellent conductor of heat. Probably only a couple of degrees difference between the cover temp and the water behind it.

Agree that some indication of temp is better than nothing. I lost an engine once because the tstat (OMC engine) froze shut and I had no way of knowing it.....locked up on me at WOT.

If all else fails, do you have room to epoxy the sender to the outside of the water jacket. JB weld has metal flakes in it and should provide pretty good heat transfer. A big blob completely encircling the sensor is what I would do. There are silver impregnated epoxies used in industry but they are pricey and I doubt necessary.

HTH,
Mark

 

[racerone]

Re: Temp sender help! 1986 Mercury, 90hp inline 6

The Johnson / Evinrude temperature sending kit used a bracket.-----Paint was scraped off the water jacket cover .---Sending unit was adjusted to firmly touch outside off the cover.---Post picture of the bits you have.