Re: 135hp mercury 2.0litre v6 help
March 08, 2016 at 12:42pm
Im not sure how familiar you are with these controls, but you are supposed to get a short beep when you engage the key. This is a feedback loop which tells you that the alarm system is working properly. These alarms are triggered for two things, low oil and overheating.
Usually a constant buzz will be overheating. A beep, beep, beep will be low oil.
I would hunt down the temp sensors in the motors and check all the wiring and grounds. If everything checks out, then start disconnecting them and see which one is faulty. There should be one coming right off the block that would be a good starting spot. This will be a PITA, and i would try your best to find a wiring diagram.
Next thing would be the horn. If it uses a contact switch, it may be corroded and 'stuck' in the closed position.