testing overheating sensor

[reddog349]

I have a 1977 evinrude 70 hp that has a sensor of sorts mounted agianst the motor over the center cylindar which ill assume is a overheat sensor.How do I test it to see that it is working? <br />I had considered taking a small torch or lighter and heating it up but was afraid it might damage it.

 

[angus63]

Re: testing overheating sensor

Remove it, throw a thermometer in a pot of heated water (appx 150° F), connect a continuity tester between casing and wire, raise temp of water until switch closes and note temp. should be appx 180°F or so. Also ground engine side of tan wire to the block to check if horn works.<br />Good luck