Whaler Central - Boston Whaler Boat Information and Photos

Posted by YatYas on 07/30/10 - 1:41 PM

Greetings WC,
I'm hoping to gain some knowledge here about my Mercury's oil alarm. beep beep beep beep beep....
I think I've narrowed it down to either: the float switch in the cowling reservoir,
motion sensor in the mixing pump,
defective ignition sending modual, or
defective alarm module...
Is there a way I can isolate any of these, to continue on with the process of elimination?
Thanks for any help!

Fight the the good fight.

Posted by mstahl1171 on 07/30/10 - 3:18 PM

Try posting you question on iboats.com (forum section). I use them for all my engine needs and they have been great help.

Posted by Tom W Clark on 07/30/10 - 7:25 PM

10:1 it's an alarm module. That is a VERY common problem on the Mercury 150s.

There are two of them on the 150 so you need to determine which one it is. Try swapping out one of them and see if the problem goes away and if it does not, swap the other one.

Posted by Bake on 07/30/10 - 8:00 PM

google mercury oil alarm. the first couple of hits will take you to a very good conversation on the way it works and how to test it out.

Posted by crbenny on 07/31/10 - 7:08 AM

I had the oil alarm problem a few years ago and what I found was a strange one. The power for the alarm module is wired in series with one of the switch boxes. The engine would loose power when the switch box would cut out, and the oil injection alarm would go off at the same time. Lots of folks thought that the oil alarm triggered a de-rate feature to protect the powerhead, but that was false. New switch boxes cured the oil alarm. Strange but true. The lesson learned was; make sure the power source to the module is steady because if there's an interuption or dip, it will sound off.

Chris

Posted by YatYas on 08/02/10 - 8:05 AM

Thanks for the replies guys.
I finally ended the beeping by unplugging the power cable that feeds the oil reservoir cap inside the cowling. I know its burning oil, the tank is always full and the 2 gallon reservoir need refilling at normal intervals. So, in theory, the ole Merc should be ok with the oil cap sensor unplugged, correct? But I still need to figure out if the problem is in the cap or with the alarm module.
I'll keep yall posted.
Thanks again.

Always fight the good fight.

Edited by YatYas on 08/02/10 - 8:08 AM

Posted by JohnnyCW on 08/02/10 - 8:34 AM

I replaced several alarm modules in my old 91 Merc 115.

The alarm module on my motor used a temperature activated snap switch for high temp alarm and a magnetic reed switch in the oil tank for low oil alarm.

If the temperature switch activated from high temp, it would close the circuit to ground activating the temp alarm.

If the oil level got low, the float in the tank would close the reed switch for the oil alarm and complete a path to ground activating the alarm.

If your module works like mine did, use a DMM, disconnect both oil sensor wires from the alarm module, and check them both for continuity to ground. One should and one shouldn't. If they both have continuity to ground, the alarm module is likely bad. Also the temp input wire should not have continuity to ground either.