1998 115 Mercury Outboard ignition warning not working

[eabkj01]

I have twin1998 115 mercury's. The starboard engine warning will not sound when you turn the ignition key. The port engine does. I have known this for awhile and this is a project boat that I have had. This has been going on since I purchased this as a project boat to keep. If I turn the ignition switch to the on position and then unplug the bullet connector for the temp sensor (tan/lt.blu wire) on the engine and ground the wire to the block the warning horn will sound for the duration the wire is grounded. So for me that means the warning horn works. What item in the system makes the warning horn sound for the test when the key is turned to the on position?? Is it the RPM Liiter which feeds off the purple wire which is the other side of the warning horn?? Another item that needs to be known is for other reasons I have installed two new ignition switches and yes the engines start etc just not the test during start. I also have a Mercury Service Manual which is mandatory for someone that does their own repairs.

 

[Laddies]

Re: 1998 115 Mercury Outboard ignition warning not working

Sounds like the oil module is bad

 

[CharlieB]

Re: 1998 115 Mercury Outboard ignition warning not working

It may be possible that the 'Self Test' circuit of the Oil Warning Module is bad.

You should test to see if the Oil Warnings function.

With the key ON, unplug the blue wires under the oil tank and touch the two wires from the module together, the alarm should sound.

If the motor has a rotation sensor on the oil pump, unplug it and start the motor, the alarm should sound.

If either test fails, order a new module.

It would not hurt to add a little oil to your fuel if you run the boat, just as an added precaution against an oiling failure just until the alarm system is functioning correctly. The additional oil will only add a small amount of smoke and will not hurt the motor other than possibly shorten spark plug life a little.