40 hp merc oil warning alarm

Is there any way to test the oil warning alarm on a 2001 40hp merc? Also for that matter what is the difference between the oil alarm and the overheat alarm. thanks

Re: 40 hp merc oil warning alarm

I have an '02 90 hp. Would imagine the systems are similar. There is a warning module that accepts info from the over temp and low oil sensors. Solid is temp and intermittent is oil.

Shorting out the sensor wire to ground will activate the respective signal from the module. The module activates the horn by shorting out the wire to the horn in whatever pattern needed to identify the type of problem. My manual is out in the shop and it is cold and raining plus I am not dressed so I can't provide you with actual colors. Tan and maybe a blue stripe is usually used for temp and I think blue with white stripe is oil......to the sensor. Don't know what color goes from the sensor to the horn, but the sensor probably has a black wire for ground and a red for power, so any other wire should be the one that goes to the horn.

Problems with oil warning systems include the magnet falling off the float in the tank.

Mark

Re: 40 hp merc oil warning alarm

Warning,
Don't go randomly grounding wires to see what happens. For instance, one wire to the motion sensor in the pump is conditioned power, and grounding it could take out the $200 module.

Get the book and follow the procedure.

hope it helps
John

Re: 40 hp merc oil warning alarm

I have an 01 40hp too and I am having the same issue. First, buy the manual at mercury parts express online.

The blue leads go to the oil, the tan goes to the engine overheat sensor. Here is the procedure you can do to check and see if your having any problems. This is from another post I posted somewhere:

According to my manual the procedure to check for either the oil switch or engine overheat sensor failures is to disconnect the leads and start the motor. If the alarm stops, then I'm to replace the sensors.
Blue lead = oil sensor
Tan lead= engine sensor
blue/tan=engine sensor (after blue and tan combine, becuase they share the same circuit)