75 mariner... need some advice on repair

Hey Folks, this is my first time posting. Have been reading lots of the great advice being given and thought I would get on board. I have a recurring problem with my Mariner outboard. The sensor located near the key switch goes off after the motor has been running about 20 min. I have replaced the impeller, the water pump, the thermostat, and tuned it up and still this problem continues. The mechanic that looked at it told me that the float in the automatic oil proportioner resevoir is working properly. Any thoughts on this and a possible solution will be greatly appreciated. The sound is a constant scream, not an itermitent thing. Could the sensor itself be bad, and if so where would it be located. Thanks in advance Mike

..."Could the sensor itself be bad?"

Heck yes! If that's a temp sensor, buy/ borrow an infrared temp gun and verify that the temp is below 150 'F everywhere on the power head. Then remove/ replace the sensor.

Jeff

Yes, my money would be on the temp sensor.

They are a simple design and built cheap AND are something that does "commonly" fail.

On a positive note, when they do fail they give you a "false" alarm which is much better than staying quiet when you do in fact have an overheat.

One for this model sells for about 55 bucks - not cheap, but about $950 less than a rebuild kit (just to put it in perspective).