Reply To: 1986 115 H.P Merc warning buzzer

[Don]

Don’t have any experience with the merc buzzers, only the OMC warning systems.. Is this set up supposed to have a warning horn with the self test feature, like the OMCs? In any event, sounds like you have disconnected the inputs to the horn but the horn is still stuck on…But again, not familiar with the Merc systems, so hopefully a merc guy will chime in to be sure you have disconnected all the possible sensor/horn inputs. If so, there is either a short to ground in the horn lead somewhere, or the horn itself is defective…
In either case, I would not just disconnect the horn and forget about it. Go through the time and trouble to find the actual issue and repair it. The horn warnings can be a valuable aid if a cooling or oiling system issue does occur….
I’m assuming that your rig uses a conventional side mount control box. It shouldn’t be too tough to split the box open to gain access to the warning horn. Once the box is split open, remove the ground lead from the warning horn. Turn the key on again or start the engine with the ground lead disconnected. If the horn still activates, the horn itself is probably the issue. Look for shorts to ground in the horn sensor lead from the control box back to the engine harness, if removing the horn ground lead silences the horn….Admittedly, I am assuming your warning horn has only two leads connected to it….
Hopefully a merc guy will chime in with a wiring harness for your model engine showing all sensors….