Critical Low Oil - 2008 200hp Optimax

[StormBreaker]

Friday I put my boat in for a sea trial after doing winter maintenance and 300 hour service. All went well but because of sea state I didnt stay out long. Well today I put the boat in to make the run to my slip and about halfway there I got a critical low oil warning. I immediately shut down and pulled the cowling to find that there were no leaks and the level was a few inches below completely full. I did a quick google search and a lot of guys are talking about the magnet failing and it being a false alarm. With that in mind I decided I would cruise for another 10-15 minutes to see if the oil level got any lower to hopefully confirm false alarm. Well about 10 minutes later the motor sputtered differently so I cut back the throttle and as I did that the motor smoked quick and then I shut it off for fear of damaging the motor. I checked the engine mounted tank again and the level didnt appear to have changed. Once in the slip a few hours later I fired the motor up, the alarm was still present but the motor seemed to run normal at idle, no sputtering. I didnt let it run for more than 5 seconds. I then cracked the cap on the small engine mounted tank which was still the same level as before and there was pressure that was released when I opened it.

I guess first and foremost I am afraid I did serious damage to the motor, but I am also really hoping this is just an issue with the sensor in the engine mounted tank. Has anyone experienced this, does anyone have any advice?

[Savage]

If the tank didn't go empty, then serious damage is not likely.

Click on this link for the next steps>>>>> How to BLEED the ENGINE MOUNTED OIL TANK when AIR IS PRESENT

[SilverFox579]

Is the remote tank at least 30% and no more than 80% full?

[EuropeanAM]

If you would, please take a moment to review the Announcements at the top of the Forum, and be sure to provide the Required Info (serial number) when posting.

NEVER, EVER "assume" that a warning horn is an error. ALWAYS go with the assumption that it is doing it's job- and screaming at you in an attempt to bring your attention to a CRITICAL, potentially CATASTROPHIC failure possibility.

In this case, it was advising you your ENGINE MOUNTED oil tank was not 100% full, with NO air space present. As the engine continues to run, the PCM is approximating how much oil you've consumed and will reduce your available power and do everything within it's power to save the engine, despite your efforts to continue running.

The PCM cannot, however, shift to neutral and turn the engine off (that is solely up to you, for safety reasons).

Before you attempt to run the engine again, let's determine precisely how much oil remains in the the ENGINE MOUNTED TANK, and how much is in the REMOTE (boat) tank.

[StormBreaker]

My apologies, the serial number of the motor is 1B698948. The engine mounted tank never went below 75% and truthfully I think this is where it was when I started running. I will attach a photo of the exact level of the tank when the alarm went off. Screenshot 2024-05-22 144256.png. The remote (boat) tank is 3/4 full.

[EuropeanAM]

In that case, you should be able to simply bleed the air from the engine mounted oil tank (see the FAQ Section at the top of this forum: "Bleeding Air from the Engine-Mounted Oil Tank".

Alarm should cease when that tank is 100% bled.

[SilverFox579]

In that case, you should be able to simply bleed the air from the engine mounted oil tank (see the FAQ Section at the top of this forum: "Bleeding Air from the Engine-Mounted Oil Tank".

Alarm should cease when that tank is 100% bled.

+1!

[StormBreaker]

will the problem persist? any idea what causes this to happen? Is there anything I can do (filter change, etc) to prevent this from happening again?

[Savage]

One step at a time. Let's see if it will bleed before making anymore conclusions.

[StormBreaker]

So the system did bleed. side note both tanks had air in them (port was the alarmed side and had noticeably less than the stbd). I bled both tanks until oil started oozing out the top and then tightened down the cover. The alarm cleared on the gauge. I took it up the river for a couple passes and the alarm didn't come back so the immediate issue has been resolved. I plan on taking the boat out later this week or weekend for a longer run to make sure the issue does not return. Should the issue return I will follow up. I have replacement filters for the inline filter ready to go and can clean the pickup screen in the boat tank should the issue return. If that doesn't resolve it then I will need some additional guidance.

Port motor (low oil alarm) has the new black air compressor on it and the stbd has the older bare metal compressor. While running with the cover off I noticed a much louder high pitched knock (quieter version of the same sound came out of the stbd motor) seemed to be coming from the fly wheel of the air compressor. I took the belt off and there was absolutely no play in either port or stbd air compressor fly wheels. I put the covers back on the motor while it was running and I couldnt hear the noise at all. Do the compressors knock normally, is this something I should be concerned with? I will try and add a video of it to this post of both motors running.

Another thing to note, there is a slight air leak coming from the bottom air hose on the port air compressor where the hose fits onto the barbed fitting. I will be replacing the hose and clamp to fix this but could that be part of the oil or loud knock issue?

[StormBreaker]

Here are the links to the two motors, the one with the plastic cover off is the port motor that had the low oil alarm and the other is the stbd for comparison.
https://youtube.com/shorts/qlR3N8EwQrY?feature=share
https://youtube.com/shorts/2qWcGp-eIx8?feature=share

[JOE54]

not normally crank bearing could be failing, careful with that flywheel cover not connected to plenum cover

[StormBreaker]

So I purged both tanks which got rid of the alarm. I also fixed an air leak at the fitting on the compressor. I ran at cruise for about an hour 15 (no alarm) and when I got back to my slip I checked the level in my tank and it had gone down again but much less than before. I am going to change the inline filters and clean the pickup screen in the boat tank. I'll purge the air again and search for any other air leaks. Any other ideas on what it could be or what I should check? This is the level of the two tanks Snapchat-1003578096.jpg

[Savage]

Did you have the motor trimmed up slightly when you bled the tank?

[StormBreaker]

Trimmed to what I was pretty sure was level

[Savage]

Trimmed to what I was pretty sure was level

Did you have the motor trimmed up slightly when you bled the tank?

"slightly",,,,,,,, This method ensures that the cap is at the highest level so ALL the air space is removed and replaced by oil.

[EuropeanAM]

^^^^ This.

Also note: Any loose caps, o-rings, clamps, etc. can cause oil level to drop while engine is sitting, or even after shutdown. It usually (but not always) causes problems with bleeding the air.

Also note that you should only remove caps from the remote tank for the time period necessary to add oil to the 80% capacity range, then reinstall the cap tight. If you need to obtain more oil, REINSTALL CAP before you begin your quest to find oil. You'd be amazed how much oil can siphon back in an hour if you leave the remote cap off.

[StormBreaker]

I replaced the inline filters between the boat tank and the engine tank today, when removing them I noticed there was no oil that spilled out from the hoses. Should there be oil in the hoses at all times? I would think yes or it would be introducing air into the boat tank once I start the motor.

It looked as if the filter wasn't fully secured into the hose and some air might have been leaking out so I put better zip ties to make sure it was secure. Hopefully that was the issue. I will also be trimming the motor up slightly as you advised.

[EuropeanAM]

There should only be ONE filter between the REMOTE (boat) oil tank and the Engine tank. This filter SHOULD have oil in it at all times.

The two RETURN OIL LINE FILTERS should also have oil in them, though they may not be "full" of oil as they simply are in the line carrying the excess oil from the air compressor to engine's main crank bearings.

[StormBreaker]

When I said filters plural I meant for both motors. I should have been more clear. There was no oil in the inline filters between the tanks so I'm losing vacuum somewhere, hopefully I found the only loss at the filter.