'96 Mercury 115 - Overheat switch location

[andersonjk4]

I have a 1996 Mercury 115 2-stroke. I took my boat out for a weekend on the lake when I launched all was good. I ran the boat to the place we were staying and everything was fine. The next morning I got up to go fishing and as soon as I turned the key on the overheat alarm started sounding. The boat was sitting all night and hadn't ran at all, so I know it wasn't overheating but the alarm was still going off. I assume this means the sensor/switch went bad (got stuck closed). I'm having trouble locating the overheat sensor on my motor. I have searched the manual and looked at the parts diagrams, but I must be overlooking something. Can anyone help point me in the right direction to locate this sensor, so I can test it and replace it. Thanks.

 

[pigeon laker]

Re: '96 Mercury 115 - Overheat switch location

Check the oil level,uses the same alarm.

 

[andersonjk4]

Re: '96 Mercury 115 - Overheat switch location

The alarm is a constant alarm (BEEEEEEEEEEEEEEEEEEEEEP) which means its the overheat sensor, not the (BEEP BEEP BEEP) that would indicate low oil level. The oil resevoir is full.

 

[ufm82]

Re: '96 Mercury 115 - Overheat switch location

It'll be in the top section of the cylinder head - single wire blue/tan maybe. (Don't know about the 115- that's what it is on my 150) Check the wire to see that it isn't rubbed against the block somewhere grounding it and causing the alarm. Obviously the horn is getting power when it shouldn't be...

UFM82