mercury alarm

I have a 1998 mercury 60 which has its alarm sounding continuous. It sounds as soon as you turn the key to 'run' without firing the engine. This happens when the engine is stone cold. I have disconnected the temp sensor but the alarm still sounds continuously. Please advise.

Re: mercury alarm

Most of those engines have an oil alarm also. Some have a module that modulates the oil alarm to an intermittent beep as compared to the OT alarm which is constant. So if you have a built in oil tank you can disconnect the light blue wires. If you have light blue and tan with a light blue stripe going to a module you can disconnect that. If that doesn't fix the problem ohm from the low side of the horn to battery neg. Should be an open circuit. If not, disconnect the 8 pin harness connector in the engine and do it again. If it stops problem is a short in the engine. If not problem in the control cable to the engine.

Re: mercury alarm

Unplug the light blue wires from the magnetic switch in the bottom of the oil tank. If this stops your alarm the problem is an adhesive failure of the magnet on the bottom of the oil level float. This is next to impossible to repair. Replace the oil tank assy.

Re: mercury alarm

CharlieB said:

Unplug the light blue wires from the magnetic switch in the bottom of the oil tank. If this stops your alarm the problem is an adhesive failure of the magnet on the bottom of the oil level float. This is next to impossible to repair. Replace the oil tank assy.

Click to expand...

Thanks. I've disconnected the blue wires to the oil tank, still the alarm sounds. So it's not the oil or the temp sensors. I presume the problem is now in the Quicksilver control box where the alarm is based? Are there any surprises there if I am to take it apart, like a coiled spring whizzing out at me once I open it?

Re: mercury alarm

It may not be in the box. It may be in the wiring harness near the box. The Commander 2000 wiring diagram shows it in the box. The 2000 mounts on the bulkhead with cables exposed. The 3000 I had earlier had it near the box. The 3000 mounts in the bulkhead with cables hidden and has the large black button.

No surprises. Just a 2 terminal 12v piezo device.

Mark

Re: mercury alarm

Does that unit not have the oil warning module located under the cowl? Those modules are a common source of failure.

Re: mercury alarm

Follow the tan wire from the temp sensor to the black box. At the wiring harness to that black box use a test light or meter to check every wire until you find 12V with the key ON, unplug that wire. That wire should be purple.

If this stops your alarm then order a new module.

There should also be a tan wire from the main harness that is 12V with the key ON. This is the wire from the horn and also connects to the temp sensor. When the sensor trips it grounds and the horn sounds.

If disconnecting the tan wire from the harness to the module stops the horn then there is a short somewhere else in the boat harness.

If you plan on running your boat before replacing the oil alarm module, you should be sure the tan wires remain connected together, that is the wiring harness tan to the sensor tan wire. This will enable an over-heat warning.

Re: mercury alarm

CharlieB said:

Follow the tan wire from the temp sensor to the black box. At the wiring harness to that black box use a test light or meter to check every wire until you find 12V with the key ON, unplug that wire. That wire should be purple.

If this stops your alarm then order a new module.

There should also be a tan wire from the main harness that is 12V with the key ON. This is the wire from the horn and also connects to the temp sensor. When the sensor trips it grounds and the horn sounds.

If disconnecting the tan wire from the harness to the module stops the horn then there is a short somewhere else in the boat harness.

If you plan on running your boat before replacing the oil alarm module, you should be sure the tan wires remain connected together, that is the wiring harness tan to the sensor tan wire. This will enable an over-heat warning.

Click to expand...

Thanks for your advice, I'll have a look over the weekend. Couple of questions if you dont mind... If the purple wire issue/ new module fixes the problem, do i still have to follow the 'tan wire' advice? Also, do you have a full part name/number for this module and is it the same as the 'oil warning alarm module' I've seen on the net?
thanks

Re: mercury alarm

chris28 said:

Thanks for your advice, I'll have a look over the weekend. Couple of questions if you dont mind... If the purple wire issue/ new module fixes the problem, do i still have to follow the 'tan wire' advice? Also, do you have a full part name/number for this module and is it the same as the 'oil warning alarm module' I've seen on the net?
thanks

Click to expand...

OK, So I've tested the purple wire, and its live 12v with Key ON. So that tells me its the module right? However, I've seen the module behind everything... how do you get it out? I've taken off the electric cover to get to the wires, what else needs to come off and how is the module bolted in? Do you need to strip down lots of other stuff to get to it as I'm approaching the limit to my confidence! Thanks

Re: mercury alarm

CharlieB said:

Follow the tan wire from the temp sensor to the black box. At the wiring harness to that black box use a test light or meter to check every wire until you find 12V with the key ON, unplug that wire. That wire should be purple.

If this stops your alarm then order a new module.

There should also be a tan wire from the main harness that is 12V with the key ON. This is the wire from the horn and also connects to the temp sensor. When the sensor trips it grounds and the horn sounds.

If disconnecting the tan wire from the harness to the module stops the horn then there is a short somewhere else in the boat harness.

If you plan on running your boat before replacing the oil alarm module, you should be sure the tan wires remain connected together, that is the wiring harness tan to the sensor tan wire. This will enable an over-heat warning.

Click to expand...

OK, So I've tested the purple wire, and its live 12v with Key ON. So that tells me its the module right? However, I've seen the module behind everything... how do you get it out? I've taken off the electric cover to get to the wires, what else needs to come off and how is the module bolted in? Do you need to strip down lots of other stuff to get to it as I'm approaching the limit to my confidence! Thanks

Re: mercury alarm

Sometimes looking at the exploded parts views helps understand how things fit together.

Have your model and serial # handy and select the 'Search with Pictures' option

The #1 web site for genuine Mercury Mercruiser engines, parts and propellers

Do you have a factory service manual? It has wiring diagrams besides having everything else about your motor.

Send me a PM with a good email address.