Low Drive Oil Warning Signal

[timrsd]

I am having a problem with my 2003 Bayliner 265 (Mercruiser 350 / Bravo III outdrive). The low oil warning signal (2 short beeps every minute) began immediately after fueling up and upon return from a 3-1/2-hour trip of constant running about 3k RPM. Thanks to other posts on this subject I checked for sludge in the bottom of the oil reservoir and found plenty. I cleaned the reservoir out and re-installed it. I got about 10 minutes running time without the alarm, followed by about 10 minutes with the alarm, followed by about 30 minutes with no alarm, and now back to running with the alarm. The engine remained on the entire time.
Later I tried disconnecting the wires at the oil reservoir to try to isolate the problem to the sending unit but still got an alarm.
Any troubleshooting ideas would be appreciated!

 

[Haut Medoc]

Re: Low Drive Oil Warning Signal

When was the last time the drive was drained?
Have you needed to add to the res?.....JK

 

[tommays]

Re: Low Drive Oil Warning Signal

Its sounds like you have and MPI motor ? which can give alarms for a lot more reasons than a standard motor

Tommays

 

[timrsd]

Re: Low Drive Oil Warning Signal

Thanks for the feedback...

The drive was "serviced" at the beginning of the year. I presume that included changing the drive oil (and I will check with the shop). I did have to add drive oil one time after the service was performed, the reservoir was in fact low and the alarm sounded; topping off silenced the alarm - that was 4 months ago. Not a peep until now.

Yes, it is an MPI engine. According to the Mercruiser power package manual, only a low drive oil condition results in an "intermittent" alarm. The other alarm conditions are low oil pressure and high temperature - both those conditions result in a continuous alarm.

 

[Don S]

Re: Low Drive Oil Warning Signal

What is the serial number of your engine, year doesn't do much after 98.

 

[hudman]

Re: Low Drive Oil Warning Signal

Thanks for the feedback...

The drive was "serviced" at the beginning of the year. I presume that included changing the drive oil (and I will check with the shop). I did have to add drive oil one time after the service was performed, the reservoir was in fact low and the alarm sounded; topping off silenced the alarm - that was 4 months ago. Not a peep until now.

Yes, it is an MPI engine. According to the Mercruiser power package manual, only a low drive oil condition results in an "intermittent" alarm. The other alarm conditions are low oil pressure and high temperature - both those conditions result in a continuous alarm.

 

[hudman]

Re: Low Drive Oil Warning Signal

Thanks for the feedback...

The drive was "serviced" at the beginning of the year. I presume that included changing the drive oil (and I will check with the shop). I did have to add drive oil one time after the service was performed, the reservoir was in fact low and the alarm sounded; topping off silenced the alarm - that was 4 months ago. Not a peep until now.

Yes, it is an MPI engine. According to the Mercruiser power package manual, only a low drive oil condition results in an "intermittent" alarm. The other alarm conditions are low oil pressure and high temperature - both those conditions result in a continuous alarm.

That is not entirely true. If you disconnect the drive resivor, there is no way it can signal a low fluid. you need either smartcraft gauges or a mercruiser diagnostic tool to tell what the beep is for. I had the same beep , turned out it was the oil pressure sensor that was unplugged...

 

[timrsd]

Re: Low Drive Oil Warning Signal

For what it's worth, the engine serial number is OM361381

 

[timrsd]

Re: Low Drive Oil Warning Signal

OK – just got back from the boat and it is as good as fixed. MarineMax sent over a mechanic with the Mercruiser computer reader, but he did not have to hook it up. Turns out that the alarm is also tied to the emissions system. The mechanic unplugged the NOX sensor and started the engine to see if the alarm condition persisted, and it did not. That result ruled out the gear oil reservoir and implicated the NOX sensor. Just having the sensor unplugged for a few minutes reset the system. The engine was shut down, the sensor re-connected and the engine restarted. No alarm (as yet). The mechanic theorized that we got a bad batch of gasoline (low octane, water, etc) which makes sense since it started almost immediately after re-fueling. The NOX sensor is located on the port side, under the exhaust manifold.

 

[Don S]

Re: Low Drive Oil Warning Signal

It's not part of any emission system, and it's not a NOX (Nitros Oxiide) sensor, it's a KNOCK sensor.
If the knock sensor detects a knock (pinging) it will talk to the ECM which will modify the timing to reduce the knocking
Your problem with that alarm is probably corrosion on the connection to the knock sensor.
Here is a section from the Merc service manual.