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Installing temperature sender on 1990 115 hp Merc 2 stroke

C

Christiaan

New member
Hello,

I am the proud owner of a 1990(?) 115 hp Mercury 2 stroke. (the one with the dual top cowlings).
Now this motor comes without a temperature sender, only a temperature switch.
My question is, is it possible to install a temperature sender in the engine's cylinder head? Because i want to keep track of my engines temperature.
If yes, where do i mount this? My thougt was near the thermostat, but im not sure. Some outboards of this type have temperature senders, but i am not sure where the mercury factory places these senders.

Another question was, within the older outboards, are the temperature senders installed in the flow of the cooling water, or do the measure the engine head temperature?

Thank you!

PS The picture below is not mine. This model is a little bit fresher, but the powerhead is the same as mine.
hqdefault.jpg
 
Last edited:
Hey christian, i bleieve i have same motor as rs.. i was thinking of adding same thing, there is a brass bolt on top right that u can remove and screw the sensor into it.
also off topic but do u get water from tell tale when ur on garden hose? I know ur supposed to, i replaced impeller and only get water from tell tale if im in the water, ive shot water straight up the water pickup tube and do get water at thermostat
 
Hello,

I got the same thing. No water from tell tale on garden hose, but in the water it is just fine. No problem there, just physics at work. In the water the water pump is below the surface. Since you took off the lower unit, make sure that the connecting rod for the water intake into the powerhead is aligned with the water pump.

Do you have a sensor for the water temp?

Check this link https://www.marineengine.com/parts/...thru-9793576-bel/cylinder-block-and-crankcase

Number #25 is the so called temperature sender. You are saying that my engine is rigged for this
 
The brass plug that Frankiea87 mentions is the place for the sensor. 41 is the sensor/sender you need to install in the place of the brass plug
 
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