Where to Install Temp Sender on 1969 Evinrude 55hp

[rdh2059]

Call me a gadget guy or a tinkerer, but I like having some kind of idea what temp my engine's operating at. This motor comes with a warning switch, which is really a binary switch - it's either on or off. I have currently jury rigged a temp sender by building a bracket that comes in contact with one of the head bolts. It works, but is WAY off, I suspect due to the minimal contact with the sender. Is there a place or way to either put mount this sender in the water jacket (Ideally) or at least some place where it would have a better reading?<br /><br />Rick

 

[byacey]

Re: Where to Install Temp Sender on 1969 Evinrude 55hp

I would think it's the top of the head that will run the hottest, and that's where you want to sense the temperature. Pick up some silicon heat sink grease from an electronics supply house and use that to thermally bond your temperature sensor to the head. You want to also shield the sensor once it is fastened from any air motion such as wind from the flywheel that would produce temperature gradients on the sensor, thus lowering the temperature reading from actual head temperature.

 

[emdsapmgr]

Re: Where to Install Temp Sender on 1969 Evinrude 55hp

I have bracket set so that the tip of the sender touches a flat surface directly on the head. (specifically, the water jacket cover). Seems to be reading properly. I use a teleflex sender p/n 523208004 (130-240 degrees.}

 

[byacey]

Re: Where to Install Temp Sender on 1969 Evinrude 55hp

For optimum heat transfer, the paint must be scraped away so the sensor is in contact with bare aluminum; paint has thermal resistance.