Bravo III Gaining Oil

JeffM

JeffM

Active Member
Oct 6, 2006
613
Magothy River, MD
Boat Info
2000 Sea Ray 260 Sundancer
Engines
5.7 EFI w/Bravo III
Last weekend we went out for a quick trip to anchor and swim, and I didn't check the bilge before we went. Today when I checked, I found drive oil on the top and side of drive reservoir, and there is a rather large piuddle of oil in the bottomof the bilge, plus a smaller puddle under the port side of the engine, beneath the reservoir.

When I last checked the levels about a month ago (we haven't been able to use the boat very much this year), the oil level was between "add" and "full, closer to "add". Now it's right up at the "full" line, definitely higher than before.

During our short trip last weekend I noticed that we had significantly less power when accellerating to plane, but were able to cruise at the same rpm and speed (GPS) as previously.

Aside from the lack of power the boat seemed to run just fine.

Our mechanic looked at the reservoir and oil and decided it was drive oil, and said he thought that the lack of power was caused by a problem with the drive, but couldn't say what the problem was until they pulled the boat and checked the drive.

Does anyone have thoughts on what's causing this? I remember reading a thread about a drive reservoir expanding but couldn't find it just now? Any help is appreciated!

Thanks,
Jeff
 
I should add that the oil is dark brown, like dirty engine oil, but not milky. It doesn't smell burnt, either.

Thanks!
Jeff
 
Seems like I remember the thread too, but I can't find it. I can't think of any way that oil from the engine could get to the outdrive. Even water from the exhaust should not be able to get there.

If the boat is kept on the water, I would worry that you have a leak and that the outdrive is taking in water where there should only be oil. I don't think oil circulates through the reservoir, so water in the outdrive would not quickly find it way to the reservoir.

Maybe others here will have better info on what it may be. Absent that, if it were my boat, I would have the outdrive oil, and water if there is any, drained tonight before I went to bed.
 
Sounds like a problem I had on a 1995 290 sundancer with a bravo3. The boat only had 100 hours on it and was only a year old. One day I was taking the boat out and after 5 minutes I heard a loud "pop" from the engine compartment. I stopped right away and opened the hatch and noticed the cap from the outdrive resevoir was missing and there was outdrive oil everywhere. Thinking I overfilled the resevoir, I replaced the cap and the same thing happened again. The problem turned out to be a lower unit bearing or race that failed. It was the most lower part of the outdrive just behind the propellers. You could grab the props and push them in and out about 1/4 of and inch. Normally you cannot move them in and out at all. While under throttle, the pressure of the propellers pushing against the gears was causing the gears to push forward and all the fluid to also pushed forward and with nowhere else to go, out went the gear oil through the resevoir. The lower part of the outdrive was replaced under warranty even though the boat was technically out of warranty. In 1995 the bravo 3 had only been out for 1 or two years and mercruiser said they had seen the problem on a few boats before. The problem was not related to a "grounding".

Hope this helps.
 
Sounds like a problem I had on a 1995 290 sundancer with a bravo3. The boat only had 100 hours on it and was only a year old. One day I was taking the boat out and after 5 minutes I heard a loud "pop" from the engine compartment. I stopped right away and opened the hatch and noticed the cap from the outdrive resevoir was missing and there was outdrive oil everywhere. Thinking I overfilled the resevoir, I replaced the cap and the same thing happened again. The problem turned out to be a lower unit bearing or race that failed. It was the most lower part of the outdrive just behind the propellers. You could grab the props and push them in and out about 1/4 of and inch. Normally you cannot move them in and out at all. While under throttle, the pressure of the propellers pushing against the gears was causing the gears to push forward and all the fluid to also pushed forward and with nowhere else to go, out went the gear oil through the resevoir. The lower part of the outdrive was replaced under warranty even though the boat was technically out of warranty. In 1995 the bravo 3 had only been out for 1 or two years and mercruiser said they had seen the problem on a few boats before. The problem was not related to a "grounding".

Hope this helps.
 
Sounds like a problem I had on a 1995 290 sundancer with a bravo3. The boat only had 100 hours on it and was only a year old. One day I was taking the boat out and after 5 minutes I heard a loud "pop" from the engine compartment. I stopped right away and opened the hatch and noticed the cap from the outdrive resevoir was missing and there was outdrive oil everywhere. Thinking I overfilled the resevoir, I replaced the cap and the same thing happened again. The problem turned out to be a lower unit bearing or race that failed. It was the most lower part of the outdrive just behind the propellers. You could grab the props and push them in and out about 1/4 of and inch. Normally you cannot move them in and out at all. While under throttle, the pressure of the propellers pushing against the gears was causing the gears to push forward and all the fluid to also pushed forward and with nowhere else to go, out went the gear oil through the resevoir. The lower part of the outdrive was replaced under warranty even though the boat was technically out of warranty. In 1995 the bravo 3 had only been out for 1 or two years and mercruiser said they had seen the problem on a few boats before. The problem was not related to a "grounding".

Hope this helps.
 
Thanks, Dave and BB. Dave, the oil was not leaking as the boat sat in the water in our slip; in fact the oil level is not at the top of the reservoir right now, but is at the "full" line, so I don't think we're in any immediate danger.

BB, That sounds familiar. Sounds like water was entering the drive oil? What did the oil look like? Was the reservoir full to the brim?

Did the dealer replace the lower unit because it was damaged or because it was under warranty?

Sorry about all the questions -- trying to get an idea what to expect and what questions to ask when they work on it on Tuesday.

Jeff
 
There was no sign of water in the oil and no oil leaking out of the drive into the lake. There was alot of "dark" particle matter suspended in the oil that was ground up so fine you could not feel it when you rubbed the oil between your fingers. The dark particles turned out to be the race or bearing that was ground up. Curiously there were no unusual sounds that gave me any indication I was having any problem. As for the oil level at the time of the incident, it had to be right on the full line because I always checked fluid levels before every outing. When I heard the "pop" noise the first time, I lost almost the entire contents of the resevoir into the engine compartment. I topped off the resevoir and after about 5 minutes of running the boat on plane, the same thing happened again. If I remember correctly I repeated this about 3 more times before I went to my dealer. Mercruiser deciced to replace the lower unit under warranty because there was no sign of grounding and they admitted seeing the problem before. The first I would look for is the propeller assembly sliding in and out of the lower gear case. If they move then you probably have the same problem I had.

Good Luck
 
UPDATE:

Okay, I'm stumped.

Our mechanic initially thought he saw water in the drive oil. Then when he drained it to remove the drive there was no indication of water. However, he did notice the oil seemed thinner than normal.

They vacuum tested the drive for one day, then pressure tested for two days. It held vacuum/pressure perfectly.

There is no fore/aft play in the props.

Prior to our last trip, the bilge was dry. No oil or water. After the last trip, there was drive oil on top of the reservoir, and a substantial amount in the bilge, under the motor. There was also some on the hull under the reservoir. It certainly appeared as though the oil in the bilge came from the drive reservoir.

During the last trip, it seemed to take much longer than normal to come up on plane. Bottom is clean, props are clean, gas is from the same source we've been using all season.

Before our last trip, the drive oil level was just above the add line -- I noticed and was planning to fill it. After the trip, the oil was at the full line. Not above, but right at the line, and definitely higher than before.

Help! Is there a problem with my drive? How else can we test?

Could the oil be from somewhere else? The mechanic checked the oil in the bilge and on the reservoir and thought they were both drive oil, though. Is there another fluid in the system that resembles drive oil? And if so, why is the oil level higher now?

Thanks in advance!
Jeff
 
I wonder if your outdrive gear oil is expanding due to excessive heat. If you do a search, you will find several postings on the board about Drive Showers designed to cool outdrives. In these postings you will notice that overheating Bravo3s have been known to actually explode the reservoirs in the engine compartment.

After a run and with the motor hot what is the oil level in the reservoir? Is it right up to the top? After the engine and outdrive have sat for a day, what is the oil level in the reservoir? If the reservoir is empty, then maybe the oil may be expanding or the drive may have been overfilled to begin with. When the drive oil is changed it requires a pump that is put in the bottom of the drive and you keep adding oil until it comes out the vent opening. Then you top up the reservoir. Make sure that's the way the technician did your oil change.
 
Dave, Thanks for the suggestions. I check the fluids before we start the motor, so up til now the drive has been cold. The levels I described above are whenthe motor/drive are cold. I'll check it after we run her for a while the next time we're out. I haven't seen any white residue on the drive, though.

The drive was serviced and the oil changed at the start of the season, and we've put about 25 hours on her since then. Could the air issues be showing up now if the drive wasn't filled properly? The reservoir's oil level had been fairly consistent before this, with just a very slow decrease in level to just above the "add" line.

What would the symptoms be if the drive wasn't filled properly (they just changed the oil again, so what should I look for)?

Jeff
 
Jeff.... I had a very similar thing happen. After a several mile run down the river I popped the engine compartment to show the father in law the goods.... found the port reservoir was bulging like it was going to pop. I always check the drive oil at the beginning of each day out and both port and starboard reservoirs were at the full line. After the run the starboard drive was still at the full line but port looked like it would pop.... fortunately the seal on the cap held otherwise I would have had drive fluid in the bilge like you did.

Opening the reservoir cap would simply allow the fluid to push its way out of the reservoir. Once home on the trailer I pulled the vent plug (top of the drive) and was surprised to have the vent plug shoot out of my hand and hit a fence I was parked next too.... there was quite a bit of pressure built up in the drive.... very foul smelling air.... once the air was belched out the drive lube level returned to normal. The cause of the air was a bearing problem where the shaft enters the outdrive which was heating up enough to cause the fluid to burn and produce that gas in the drive.

The bulging drive was bulging hot or cold.... did not matter... as the gas was already produced and had no where to go (at least we know the drive was sealed well :lol: ). We also experienced the power loss you describe. The end of this story was a drive replacement under warranty. Sorry for the potentially bad news :smt009

I got a bad feeling when I read your symptom statement... as it is identical.... it just looks like my reservoir cap held and allowed the oil bottle to bulge. The bulging was so bad that the reservoir bottle had to be replaced as well as it had been stretched. I hope this is not the case with your drive.... but boy it sure sounds exactly the same.
 
Pressure in the drive enough to blow off the vent plug as I unscrewed it.... and splatter drive fluid every where.

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196019642-L.jpg


not fun to clean up either :smt009
 
Jeff...............(I didn't see Jeremy's reply before I submitted this but he and I are probably guessing the same thing at this point.

That's what I get for walking away from the computer in the middle of typing a reply :smt021 :grin: )

If your reservoir is back down again (or empty) when the engine is cold, then heat may be causing the problem since the oil might be expanding way too much if the heat buildup in the drive is excessive. Then it will loose that volume when it cools thus causing the reservoir to empty out as the oil drains back into the drive.

If that turns out to be the case then the big question is what is causing the heat? I don't have a lot of ideas on this one except you said it is a relatively new problem and your boat doesn't seem to get on plane as easy anymore suggesting that (maybe :huh: ) something might be binding in the outdrive itself causing excessive friction and heat build up............and that just a guess on my part. I think I would ask the Technician to call Mercury if he doesn't have any other ideas at this point and describe everything you have observed including the performance issue and maybe they could give him some other things to check out.

As far as the oil fill goes, I only mentioned the fill procedure if there is the slightest possibility he may not have done it correctly. You may just want to ask how he did it. Incidentally, the "bottom up" method is to purge trapped air thru the vent hole and when the oil reaches the level of the vent hole, then the outdrive is full. At that point both plugs should be put back in and the reservior topped up to the correct fill level.

Dave
 
Thanks, Dave and Jeremy! I'll pay close attention to the drive fluid level next time we're out -- may not be for a week or so this time of year :smt089 .

Our mechanic is going to sea trial her this morning, though, and I'll pass along your suggestions. When I spoke to him yesterday he didn't have any ideas about possible causes. Now we have something to start with -- just one more example of this board's terrific value.

One more question, though -- could overheating cause the drive fluid to break down and become thinner? When he changed the oil, our mechanic said it looked thinner, although there was no sign of water.

Jeff
 
I don't know about thinner, but ask him if it looked darker than normal or smelled "burnt". From what I understand both are a sign of overheating.
 
the stuff that came out of our dead drive was very black.... the oil, smell was very acrid and the viscosity seemed significantly less than new (thinner).
 
Thanks again, guys.....the oil in the bilge was quite dark, but I thought that was from the bilge itself. The oil residue on top of the reservoir didn't look too dark, but it was not a very thick layer and may have been an illusion.

The marina manager called and said that the mechanic sea trialed her this morning and he thought everything seemed fine. We are going to take her for a ride this afternoon and I'll pay particular attention to the oil levels and before and after. I wonder if this is something that may take time to show up after an oil change, or if it'll be apparent pretty quickly...after perhaps an hour of runtime?

Jeff
 
Jeff

I would be real carefull at this point based on what Jeremy experienced. If something is binding or starting to fail in your drive, it may still be fixable. I don't want to sound like an alrmist, but if it were my boat I don't think I would be using it until I get something figured out.

I still think you need some help from a real expert on the B3 drives or directly from Mercury to try and get to the bottom of the problem before the drive gernades itself.

Dave
 
Okay, I think we have a problem.

Thanks to Dave and Jeremy's advice, we took a very cautious approach to the sea trial. I checked the oil level prior to starting the engine: right on the "add" line. The engine was still slightly warm from our mechanic's ride this morning, but only barely warm to the touch. There was no oil on the reservoir, bilge, or stringers under the reservoir. Motor oil and powersteering fluid levels were fine.

There is run of about 15 minutes at no-wake speed to the open river. We ran at 1000 rpm to the end of the no-wake zone, checked the oil level: it had increased to about 1/4 of the distance between "add" and "full".

Took her up on plane. She planed out just fine, even coming onto plane at three-quarters throttle. Much better than last time out. However, I did notice a very slight surging that could very well have been my imagination. After about 5 minutes, if that, I stopped and checked the oil level: it was now 1/2 way up to "full".

Ran at about half throttle back to the start of the no-wake zone, and by then the oil was up to 3/4 of the way to "full".

Docked and checked it again: it was almost back down to "add".

Could the drive and oil cool down enough in that amount of time (15 minutes) to causes such a drop in level? Is it normal for the drive oil level to fluctuate so much?

The mechanic who did the work and the test-run this morning was not working this afternoon, but the marina manager said that he checked the condition of the old oil and saw no metal flakes or shavings, milkiness, or other abnormalities in the oil.

Jeff
 
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