buzzer wont quit

I have a 1990 90HP mercury out board . I have a buzzer that goes off at times . It is a constant buzzing high pitch the same buzzer as the one that beeps when you turn your switch on . Now i took it in to shop a couple years ago and they changed the oil resovoir and told me it was the low oil buzzer well guess again . Now it doesn't do it all the time and never did just getting more frequent .It is random and when it went off last time I felt the head nope cool and not the same buzzer sound . I have watched the oil injection levels since I bought the boat new and can tell if it is using enough or same amount as usual and it is . what I am needing due my thoughts are I have grounded wire so if any one has a wiring diagram i would appreciate it or if any one can figure the buzzer out or has some ideas they wold be appreciative . I have quicksilver controls. If you turn the switch to the left a little it stops buzzing but kills all instruments but motor runs great at that time that is what makes me think it is a short . I also changed the ignition switch . Still buzzes . hate to go fishing other than the buzzer the boat is great . the only thing that i havent done is cut the wire to the Buzzer but I am an old mechanic and know better

Thanks

Re: buzzer wont quit

Could be a short in the wiring, or a defective overtemp sender. It's only a cheep klixon switch.

Try disconnecting the overtemp sensor just to see if the nuisance goes away. If it does, replace the part and wire it back in. If it doesn't, start checking out the alarm wire as it snakes through the harness, controlls, and dash harness.

hope it helps
John