1995 Merc 200 EFI, Oil Alarm - Please help!

Hello, my first post, I'm hoping someone can help me.

Problem: Oil Alarm (fast, constenet beeping) will not stop.

Due to an accident, I was unable to use my boat for a long time (2.8 years). I had her tuned up and everything seemed great. During our last tournament I made a 15 mile run, 1/2 way back (after a successful spot hop catching my limit) my Oil Alarm started going off and would not stop.

Status:

1. The alarm continues no matter what I do.
2. The top oil resivour is full.
3. The main oil resivour is full.
4. The float switch is working properly (tested it with a meter).
5. The engine smokes a little at startup so I think it's getting oil.
6. The engine runs great, no hesitation, sputtering, everything seems great.

I don't know how to determine if the oil pump on the motor is working and where the alarm switch is on the motor. Will these alarms sound if it's low (versus) no oil? If it's not the oil pump on the motor, what else could it be?

Any and all help is very much appreciated.

Sincerely,
Grumpy Bass

Re: 1995 Merc 200 EFI, Oil Alarm - Please help!

The oil/overheat alarm module compares the pulse from the rotation sensor on the oil pump to the ignition pulse on the green wire to oil of the ignition coils.

Any un-evenness between the two and the module thinks there may not be enough oil supplied.

You problem could be as simple as a failing alarm module, a poor wiring connection on the green wire between the coil and alarm module, a failing ignition module beginning to intermittently NOT fire that cyl, to a slipping oil pump drive gear on the crankshaft.

To be cautious, pre-mix your fuel at a 40 : 1 ratio, if there is an oil supply problem it should save you motor, if it turn out to be an electrical issue you may shorten the life of a set of spark plugs.

Re: 1995 Merc 200 EFI, Oil Alarm - Please help!

I have a 1993 150XRi- (efi unit) and had the issue- here is the troubleshooting:

If you are having a problem with the alarm beeping at you on your Merc and you know it has oil in both tanks, here's a step-by-step to diagnose the problem. First of all, run the engine on a remote tank of 50:1 just in case you DO have a failure.

Run the engine to recreate the conditions sounding the alarm. Do these tests while the engine is running and the alarm is beeping. Be careful- the flywheel is very close to your hand. Keep sleeves, watches and other objects that can catch on the flywheel away. Once the alarm starts, I would first unplug the blue wire from the oil reservoir cap. If the alarm stops, either the oil level sensor is bad or the level is low. Next I would disconnect the green wire going from the alarm module to the #4 coil wire terminal on the switchbox. If this stops the alarm, either the rotation sensor is bad or the pump isn't rotating. If the alarm does not stop reconnect the green wire and unplug the white and blue/white wires to the rotation sensor. If this stops the alarm, check for no spark on #4 cylinder. If the alarm does not stop disconnect the green, white and blue/white wires. If this stops the alarm, then either the pump is not rotating, the rotation sensor is bad, or no spark on #4 or the alarm module is bad. If the alarm still does not stop, disconnect the solid blue, blue/white, white, and green wires, if this still does not silence the alarm, then the alarm module is bad. You will single out a bad component in each step, eliminating each item as you go. You can check the rotation sensor by checking its output. Turn the key on, leave power wire connected and rotate the engine. You should get 1 pulse of 5 volts for every 2 rotations. You'll need to have the plugs pulled for this test so you can turn the engine safelt and easily.


That's the way I was able to finally diagnose my issue. The module is bad and will have to be replaced.

UFM82

Re: 1995 Merc 200 EFI, Oil Alarm - Please help!

On that engine the water switch in the fuel/water seperator is hooked into the oil tank circuit. Drain the water and the alarm will quit.

hope it helps
John

Re: 1995 Merc 200 EFI, Oil Alarm - Please help!

Unless the red light is on for the water module, it isn't that. Those typically live. It's the freakin' $258 module that croaks.

UFM82

Thank You!

Thank You!

Wow, your responses are fantastic, I can't wait to but them to the test tomorrow.

I'll let you know what happens.

Thanks a million for sure!

Grumpy