What's this sensor?

[Noboatmechanic]

I have a 2003 Mercury 50hp 4 stroke that has the constant alarm going off. Tried disconnecting the temp sensor to no avail. When I pull this sensor the engine revs up and the alarm goes off after a couple beeps.

For some reason I can't post the photo here. It can be found at this link: https://www.dropbox.com/s/hrqnwct2hmlawf6/IMG_20170701_144813.jpg?dl=0

What is this? I changed the oil and it's full. It's "peeing" solidly.

Any help is appreciated...

 

[RCO]

Oil pressure switch. It would be a good idea to put a mechanical gauge on the port to verify oil pressure before replacing it. Most times when an oil pressure switch is bad, they will leak.