Brave III Outdrive Fluid Level

[Nacho Boat]

OK.....I have not gotten in a stupid queston, so here goes:

On my Mercruiser 5.0L MPI Bravo III outdrives, I have had to add gear lube to keep the resevoir topped off. Over the past 100 hours, I have added about 1/2 quart in my port side, and about 1/4 quart in my starboard. Combined, less than a quart total for both drives.

Now, this bothers me, where is it going? My bilge is dry as a bone, and when any water does go in the bilge, there is absolutely no indication of any engine or drive fluid.

Is this normal? (A friend tells me that this is normal for these drives, but I don't believe it). My previous boat had a V-P engine, and I NEVER had to put a drop of fluid in the outdrives (put over 150 hours on them).

Can anyone shed some light on where my fluid is going?

 

[garryowen]

no not normal.
the fluid level would and should change from setting cold to a higher level in the bottle after running and warming up the drive but that's it.
you are right to be concerned. if not leaking in the boat it is leaking into the water and if the drive oil is leaking out then there is a good chance water is leaking into your drives..

drive oil doesn't just evaporate

 

[Nacho Boat]

if not leaking in the boat it is leaking into the water and if the drive oil is leaking out then there is a good chance water is leaking into your drives..

drive oil doesn't just evaporate

I agree and understand your point, but there has been no water in the drives. I have been watching this carefully.

 

[highslice]

That's not normal. If the oil in the reservoir is "milky" looking, you've got water leaking into the drive. We had a bad prop shaft (it had a scratch and the o-ring wouldn't seat properly) and oil was leaking out, but no water was leaking in. The drives need to be preasure tested to see where the leaks are.

 

[garryowen]

in this case what i would for piece of mind.

drain both. refill and make sure no air pockets- drive at proper angle

mark reservoir and maintain a constant watch making sure all conditions are same every time you check level. temp and drive trim level as well as boat angle(if on trailer)
if your positive your not getting water intrusion then you can watch and not do permanent damage till you solve the mystery

other than that you could have the drives vacuum tested for leaks.

it seems strange both would leak the same way at the same time.
i would have to wonder if when serviced if, they wernt filled properly and some air pockets were left, later to be filled with the drive oil it as it burped from use?

 

[rabyers1]

Some believe that the Bravo III drives can run hot enough that expansion occurs in the metal components. When this occurs you can get some "blow-by" of fluid at the shaft seal. This is most likely to occur during long runs and in warm water. The theory with this condition is that it is very difficult to detect because by the time you / your mechanic does a pressure test on the drive, it has already cooled, the metal shrank back to specs. and no leakage occurs in the test. That is also why you don't see any evidence of drive fluid in the water while the boat is at rest - it is only escaping into your wake while you're underway on a hard run. This theory is held by the companies that sell "drive wash" systems. I do not know know if it is true, but I was losing fluid in my drive after long runs and after installing a passive drive wash system (stainless steel tubes that pick-up water and dump it onto the upper gearcase housing) - my fluid loss has been reduced to almost nothing. Also, the drive wash looks very cool from behind the boat - you can see it when you are tubing, etc. I know you will get some resonses here that the drive wash theory is hog-wash. But it seems to have worked for me. And if it keeps my expensive BIII running cooler I figure it has to help with its longevity.

 

[Tonka Boater]

I'm curious to hear some more opinions on this. My understanding is that gear lube is consumable and that topping it off on occasion is normal. I topped mine off at least twice last summer and I don't have any signs of trouble. Marine Max just performed the 100 hr "A" service and removed the outdrive, aligned, etc and everything was normal.

I'm not convinced that you have anything to be worried about but I could be wrong.
.

 

[skolbe]

The drives have uni-directional seals and allow for some blow-by, but they are suppose to let gear lube out but not let water in. A mechanic told me in the fall when you change the gear lube - fill the reservoir to the top of the bottle. Come spring check it - but it should drop to the full line. Well he was correct with my 260. So - I think early after you change gear lube you lose a few air pockets, where it can drop a bit. You may want to have your drive checked at that level of consumption. I had a drive shower on my 260 after the first season, not sure if it was psychological or real - but I felt that it worked. I never had the white chalky stuff on the drive after installing it. I also thought the gear lube smelled better when changing it after the drive shower was installed.

 

[dan313]

I am going through the same problem:huh:.

I added 2oz of gear oil on monday. And on thursday it was 2oz short. I pulled the drive and did not find any oil. Also the bildge is bone dry.

I took the drive to the mec this afternoon and he is going to check it out.

I'll keep you posted.

 

[magredoak]

I have added to the starboard outdrive all summer, but none to the port outdrive. Total added is about one quart over 30 hours of use. No oil in the bilge, and no oil in the slip, so it must just leak while under way. The mechanic pulled the outdrive and did a pressure check, but no leak was found. It's still under warranty, so I'll keep watching.

 

[SeaRay]

I have had to add oil to my Bravo 3 as well. I don't seem to have any issues or see any oil in the bilge.

I was concerned too. I have added more than half a quart over the course of the season (80 hrs??).

This was the third summer with the boat. I don't recall ever adding any the first 2 years. But it was winterized somewhere different. Maybe they were filling the reservoir bottle completely.

I winterized myself last year and we just went to the fill line.

 

[Nacho Boat]

That's not normal. If the oil in the reservoir is "milky" looking, you've got water leaking into the drive. We had a bad prop shaft (it had a scratch and the o-ring wouldn't seat properly) and oil was leaking out, but no water was leaking in. The drives need to be preasure tested to see where the leaks are.

Yep....been there, done that.

When I bought the boat 10 months ago, I had water in one of the drives. Turned out to be a bad prop shaft (funny...the mechanic told me he had rarely seen one).

One month, later, my other outdrive was leaking fluid on the parking lot. Took it to my local sea ray dealer (different mechanic). Again, a bad prop shaft. Dealer told me that they had never seen one. Now I had two.

So, both drives had a leak, and were serviced and pressure tested (in the past 8 months). Fluid looks great in both, absolutely no sign of moisture.

 

[Lazy Daze]

I recently noticed my drive fluid creeping down. In my case, the rubber o-ring that seals the top plate of the drive was leaking. Actually, "is" leaking since the o-ring is still sitting on my workbench. This sits above the water line, so you should be able to see evidence of it.

 

[Nacho Boat]

Some believe that the Bravo III drives can run hot enough that expansion occurs in the metal components. When this occurs you can get some "blow-by" of fluid at the shaft seal. This is most likely to occur during long runs and in warm water. The theory with this condition is that it is very difficult to detect because by the time you / your mechanic does a pressure test on the drive, it has already cooled, the metal shrank back to specs. and no leakage occurs in the test. That is also why you don't see any evidence of drive fluid in the water while the boat is at rest - it is only escaping into your wake while you're underway on a hard run. This theory is held by the companies that sell "drive wash" systems. I do not know know if it is true, but I was losing fluid in my drive after long runs and after installing a passive drive wash system (stainless steel tubes that pick-up water and dump it onto the upper gearcase housing) - my fluid loss has been reduced to almost nothing. Also, the drive wash looks very cool from behind the boat - you can see it when you are tubing, etc. I know you will get some resonses here that the drive wash theory is hog-wash. But it seems to have worked for me. And if it keeps my expensive BIII running cooler I figure it has to help with its longevity.

Well, if this theory has any merit....I certainly have had some long runs in some very hot weather (and warm waters).

How much does it cost to purchase and install a passive drive wash system?

Thanks....

 

[Lazy Daze]

Use the term drive "shower" as you search around. That should return much more results.

I can't comment on which ones to buy or how much to install, but it looks pretty simple.

For example: http://www.driveshowers.com/index.html

Normally, I wouldn't recommend adding extra stuff like this. At least not until you can verify if your problem is indeed over heating. Otherwise, you're just masking the problem.

However, the fact that both drives are having the same problem certainly raises a question.

Just curious - you've got the Merc Hi-Perf lube in there?

 

[Summerwind]

I too have the same issue as well as other Formula owners. I was told that my inner prop staff seal was the issue, warranty paid for it however it didnt fix the problem.
I agree with Rabyers1. That when the drive get hot it exspanse and the lube thins out.

 

[rabyers1]

I am certainly no expert on this, but it seems that any mechanical components that can be helped to stay cooler during operation will have a longer service life - certainly works on your internal combustion engine with raw water flowing thru the block. I spent less than $300 on my stainless steel shower drive. It was very easy to install. It has 3 attachment points. Two are at the trim ram bolts and the third is at an upper gearcase bolt. I have observed the shower in action while running on plane from a tube towed behind the boat and it dumps a great deal of water onto the upper gearcase housing. It just looks like it is cooling down the lower unit. In addition to my lube use dwindling to almost nothing, my lower unit no longer gets that white, chalky appear in the paint. Just seems like a cheap protection plan to me.