mercury black max-warning horn

[JohnnyJ]

I have a 150 Black Max engine. A warning horn has recently started to go off when I start the engine and sometimes continues for the full time on the water. It is not the beep beep sound that the oil injection would make. It is a continuous horn that comes out from the Throttle/shift box in the cockpit next to the steering wheel. Any suggestions would be appreciated.
Many thanks JohnnyJ

 

[Windykid]

Re: mercury black max-warning horn

sounds like your overheat horn. But if it stays on when you first start it, sounds like a sending unit is bad. Disconnect the tan wire to the sending units and see if the horn goes out if it goes out the senders are bad if it stays on then the module is bad.

 

[JohnnyJ]

Re: mercury black max-warning horn

Thanks for the quick response. Am I right that the sender is on the engine and the module unit is inside or the throttl. shift box??

 

[Windykid]

Re: mercury black max-warning horn

You got it, the module is in the chift box.

 

[JohnnyJ]

Re: mercury black max-warning horn

Another question. I noticed that the trim gauge is not working. Is there a possibility that this gauge could be the cause of the constant horn? I did disconnect the temp sensor at the engine and the horn continued to give me a head ache. There is a purple wire that connects to all 3 gauges:temp, trim, and tach.