1992 Merc Black Max 150 Warning Horn

[bassinT]

I can crank the motor when I first put it in the water and it will run as far as I want to go without the warning horn sounding. However, after I shut the motor down, and then turn the key back on, the warning horn will sound (even after it has been off for several hours) and it will not quit buzzing even before I have cranked the motor. When I crank the motor the warning horn continues to sound even though plenty of water is coming out the telltale. After the boat sits for 24 hours or longer I can crank it with no warning horn sounding until I run it and then start to crank it again.

 

[baylake07]

Re: 1992 Merc Black Max 150 Warning Horn

Have the warning control module checked. This will be your problem most likely. If it is faulty it's an easy, cheap fix. Anyone quilaified will also be able to tell exactly which system is bad if the module is not faulty. This is the only way to fix your problem.

 

[WillyBWright]

Re: 1992 Merc Black Max 150 Warning Horn

Beep beep beep or beeeeeeeep? Rapid beeping? Ghostly sounds from the alarm?

Key-on cold motor possibilities...

Beeeeeeeep:
Shorted overheat sensor
Bad warning horn
Bad waring module

Beep beep beep:
Low oil in the on-motor oil tank (has to be full all the way up the neck)

Rapid beeping or ghostly sounds:
Bad warning module
Bad warning horn

 

[Texasmark]

Re: 1992 Merc Black Max 150 Warning Horn

On a '95 150 the problem was a semishorted port side thermal sensor. Sensors are easy to check. Get an ohmmeter and disconnect the leads from them one at a time. Measure across (lead to engine block) and you should read an open ckt. Anything else is a failure and it needs replacing........unless the water jacket/water in it is above 195F.

Mark

 

[bassinT]

Re: 1992 Merc Black Max 150 Warning Horn

Thanks for the replies. It's the Beeeeeep (overheating)that won't stop. I've disconnected the oil injection and manually mix my oil, so I've got the oil warning diconnected. I wasn't sure how to check the sensors...so thanks for the info on how to use the ohmeter to check them.