Water leak in bilge from Bravo 1
 

Long time reader of offshore only, 2nd time post'er. :rolleyes:

Anyhow, I am really stuck :hothead: ....Due to a water leak (approx 1 gallon in 15 min) from the starboard stern drive (Bravo 1), and after reading the offshoreonly forms and the mercuriser manual, I decided to tackle replacing the U-joint bellow, gimball bearing and the shift cable bellows on both stern drives on my 1991 Baja 290. When I opened up the u-joint bellow from the starboard drive there was really no signs of major leaking, and the same goes for the shift cable bellows. The port side had no signs of water leaking in any of the bellows. I had some surface rust on the starboard u-joints but no rust on the gimball bearing. After replacing all the bellows and following the mercruiser directions to the T, I still have the same leak in the starboard drive unit. My question to this form is.......is it possible that the gimball housing is leaking between the housing and the transom plate? Possibly near the bolts at the bottom of the gimball housing where the gimball housing attaches to the transom? I feel pretty confident that I replaced the all the bellows correctly and that my leak is coming from somewhere else, and I have no idea where a major leak could be coming from. Any help would be appreciated.

Re: Water leak in bilge from Bravo 1
 

check the upper steering shaft seal

Re: Water leak in bilge from Bravo 1
 

Silent choice? A friend had a leaking o-ring seal where the bull horn (y-pipe) bolts to the transom assembly. With that size of a leak, should be easy to pinpoint down the area of the leak. I've had to use small mirrors to check along the transom for leaks. You can also back the boat into the water in small increments to see were the water level needs to be to acheive the leak inside. Also check were the Mercadone unit is under the gimble housing were the wires go inside.

Re: Water leak in bilge from Bravo 1
 

Could it be from the Speedo tube?

Re: Water leak in bilge from Bravo 1
 

Thanks for the fast replies!!

After reading your post and about things.... Looking from inside the bilge I see the water running from the bottom plate of the transom assembly. It is almost like this plate was designed to direct leaks and act as a waterfall for my personal boat torture!!! :hothead:

Today after doing the repairs and putting the boat in the water for the first time. The boat was on the trailer and the leak was not present. But when I finally backed the boat into the water the leak appeared. But then again, I am not too sure how far the drives are in the water when the boat is on the trailer. I know the lower unit is in the water, but that is about it. I will do as US1 Fountain suggested and back the boat into the water in increments to see where the leak is coming from.

I was suspecting the upper steering shaft seal, but shouldn't I see water up there when looking through the bilge. I saw no water near the upper steering shaft seal. Or possibly, is the water running down from the steering shaft seal along the sides of the gimball housing to the bottom plate? But then again... it wasn't until the upper part of the gimball housing was in the water that the leak appeared again. If I were a betting man (I am) I would say the leak is originating from the bottom of the gimball housing.

Payton thanks for the idea about the Speedo tube and this did cross my mind. I have thoroughly examined my possible leak sources and I am sure the leak is coming from the drive unit. I have no exhaust, cooling or Speedo tube leaks, water is coming from the plate underneath the drive shaft.


Thanks for the ideas and help

Re: Water leak in bilge from Bravo 1
 

Thanks for the fast replies!!

After reading your post and about things.... Looking from inside the bilge I see the water running from the bottom plate of the transom assembly. It is almost like this plate was designed to direct leaks and act as a waterfall for my personal boat torture!!! :hothead:

Today after doing the repairs and putting the boat in the water for the first time. The boat was on the trailer and the leak was not present. But when I finally backed the boat into the water the leak appeared. But then again, I am not too sure how far the drives are in the water when the boat is on the trailer. I know the lower unit is in the water, but that is about it. I will do as US1 Fountain suggested and back the boat into the water in increments to see where the leak is coming from.

I was suspecting the upper steering shaft seal, but shouldn't I see water up there when looking through the bilge. I saw no water near the upper steering shaft seal. Or possibly, is the water running down from the steering shaft seal along the sides of the gimball housing to the bottom plate? But then again... it wasn't until the upper part of the gimball housing was in the water that the leak appeared again. If I were a betting man (I am) I would say the leak is originating from the bottom of the gimball housing.

Payton thanks for the idea about the Speedo tube and this did cross my mind. I have thoroughly examined my possible leak sources and I am sure the leak is coming from the drive unit. I have no exhaust, cooling or Speedo tube leaks, water is coming from the plate underneath the drive shaft.


Thanks for the ideas and help

Re: Water leak in bilge from Bravo 1
 

Try running a bead of silicon around the transom plate on the outside of the boat and see if the problem stops. I know it is not the best way to stop it but, I know it does work and it would tell if it is from the plate. Dwight

Re: Water leak in bilge from Bravo 1
 

I had a leak in the same general area and it ended up being the metal Y-Pipe for the silent choice. It sits below the water line and it had corroded to where exhaust pressure punctured a hole at planing rpms.

Not sure what plate you're talking about. If you do find the leak and it's a hole in metal, use JB Weld. Get a stainless metal screw that will fit the leaky hole. Use the screw to hold the JB Weld in place and let the stuff cure overnight. Stuff worked like a champ for me.

Re: Water leak in bilge from Bravo 1
 

My bet is on the Y pipe if you have silent Choice. A little 5200 and a sheetmetal screw into the hole took care of my fix

Re: Water leak in bilge from Bravo 1
 

Check the bottom two bolts on the transom assembly. Merc made these anodic bolts (sacrificial anodes) for some dumb reason in the early years. My on 1988 b1s had them. They can be major leakers.

BT :cool:

Re: Water leak in bilge from Bravo 1
 

Johnnyboatman hit it on the head. I had the same problem. Took three tries to determine where it was coming from. Mine was a 1991 model as well. This problem starts showing with boats of this age.

Re: Water leak in bilge from Bravo 1
 

Although my bet is on the y pipe, tighten the bolts of the inner transom plate (about 70 ft lbs but not sure). They can loosen over time (I don't want to mention what one of the reasons could be). This will tighten up the large foam o-ring that is in your gimbal housing. Also put a bead of 5200 around the gimbal housing.

A gallon every 15 minutes is A LOT. I'm still betting on the y-pipe.

Re: Water leak in bilge from Bravo 1
 

MOST COMMON LEAK IN THIS AREA IS THE SEAL ON THE SWIVEL SHAFT. A PAIN IN THE ASS TO FIX. THE MERC SWIVEL SHAFT WILL RUST AND TEAR OUT THE SEAL. THE GIMBAL RING MUST BE PULLED OUT.I MAKE A KIT THAT WILL SAVE YOU A WHOLE LOT OF TIME & SWEARING. IF YOUR GIMBAL RING IS WORN WHERE SWIVEL SHAFT GOES THRU IT WE CAN REPAIR RING MUCH CHEAPER. THIS WEAR WILL ALSO TEAR OUT SEAL AND CAUSE RUST & LEAKING. IF THIS IS YOUR PROBLEM CHECK MY WEB SITE AT WWW.JRMARINE.COM, CLICK ON COVER PLATE INSTRUCTIONS. WE ALSO MAKE A HP SWIVEL SHAFT OUT OF 17-4PH MATERIAL UNLIKE MERCURY'S JUNK MADE OF STEEL. RON BENDER 216-390-1330

Re: Water leak in bilge from Bravo 1
 

I was going to say one of the grommets for the k-planes indicators if you had them, but it sounds like it's around the transom plate.

The reason you won't see much water until deep is a simple matter of water displacement. Meaning not enough weight per square inch exerted against the water/hull to create enough pressure to come in a small breach. Best of luck to you. It's one of those irritating little problems...

Re: Water leak in bilge from Bravo 1
 

5/25/04 UPDATE:

First off I appreciate everyone’s input! The input from this website has provided me with insightful information and thought to tackle this problem. This is a great and informational website, not to mention the helpful and knowledgeable members! :drink:


OK......I think I have a suspect :eureka: .......On my 91 Bravo 1 gimball housing there is a small manifold attached by two bolts to the bottom of the gimball housing. This four hose manifold is for the hydraulic lines from the trim cylinder pump (in the bilge) to pass the high pressures lines thru the transom and down and out of the gimball housing. Last night I removed the small hydraulic line manifold, sacrificial anode and replaced the gaskets, for both items. I also added a good bead of 5200 between the manifold gasket and the bottom of the gimball housing. It is going to be a pain in the arsk to get this off later, but I wanted to be sure it was sealed up good!

Also, following everyone’s suggestion I also put a nice thick bead of 5200 around the seal between the gimball housing and the transom. Again, I wanted to be sure to eliminate leaks around the gimball housing. In two days I am going to slowly back the boat into the water looking for leaks. If this doesn't solve the leak, then it is probably the swivel shaft seal. I have been hoping and praying :eek: it won't be the swivel shaft, but we will see in two days. I will post everyone with the results.


BTW....Unfortunately, I do not have silent choice exhaust. I have thru-hull only exhaust so I don't have a y-pipe for exhaust fumes.

Re: Water leak in bilge from Bravo 1
 

GOOD LUCK:cool:

Re: Water leak in bilge from Bravo 1
 

That doesn't matter. When the y-pipe is not used for silent choice, a block off plate is used in place of it. They both use the same funky u-shaped o-ring and 4 bolts.
Next time for sealant, better off to use 4200. It is just as good as 5200, but not as permanant.
Good Luck

Re: Water leak in bilge from Bravo 1
 

Is you swivel shaft seal below the water line? Mine is not and the seal could be completely gone and no water (per se) would come in.

BT :cool:

Re: UPDATE: Water leak in bilge from Bravo 1
 

Well the cause of my leak is the upper swivel shaft. Slowly backed the boat into the water and no leak until the top of the gimball housing was below water. I put several paper towels in different positions in the transom hole and the upper towel was completely wet. After this I reached in and found tons of rusted metal from the swivel shaft. LEAK FOUND!

I wish I had asked the OSO board before I started this project and investigated my leaks before removed the drive and replaced everything. Well I guess you live and turn wrenches! I am going to have to re-do everything again.

For the repair, I am going to go with Ron at JR Marine and try to use his swivel shaft repair kit along with his stainless steel swivel shaft. I will post everyone with the results when I am finished. Thanks for everyone’s help!

LL

Re: Water leak in bilge from Bravo 1
 

You can tell if its the upper seal by spraying a garden hose in that area while watching in the inside of the boat.On mine the seal was boarder line under water.I didn't clue in until I had a bilge pump failure and water started accumulating on non rainy days.As it took on water and sank more it would fill more aggresivly.I needed a new steering shaft and bushing due to rust.The bore where the seal goes was pretty coroded so I used some adhesive to hold it in.I think it was rtv black or possibly eurethane.That was three years ago and its been good to date.The transom plates are pretty cheap on the amount of metal used.I would rather pack a few more pounds and have that whole plate be solid alluminum.WhenI did mine I pulled the motor as I was not keen on drilling the transom plate.It's a crap job hooking everything up when reinstaling the gimbal ring (too many hoses in too small of place).Good Luck!

Re: Water leak in bilge from Bravo 1
 

LLcoolBaja,

Upper swivel shaft is probably the worst project I had ever tackled on my boat. My boat spent some time in the salt water environment. I guess it does not matter as the swivel shaft is made out of steel. Immediately will rust. Weak Mercruiser design. Anyway, good luck with the project. Getting the nut off of a rusted swivel pin is a nightmare. I had to use a jigsaw and cut the swivel pin in half just to get it out (badly rusted). It took about 12 blades as it is about 1" round and about 12 hours, most of this with foul language. Count on $202.00 for the swivel pin alone. Worst part about mine, in the top of the transom plate where the pin fits, the small metal ring had fused itself to the transom plate. When I put the new pin and seal in, it did not make a perfect fit. End result, continued water leak after I got it back together. Got it fixed now, but do not wish this project on my worst enemy. Sorry for the bad rap on this project, just telling it like it is.

Re: Water leak in bilge from Bravo 1
 

Your Parts Shipped Today. Call Me For Any Help. Iv Done This Many Times. Ron Bender;)

Re: Water leak in bilge from Bravo 1
 

I had a similar problem with water leaking from my bravo I. Found it by using a water hose around the outside of the drive. When I directed water into the port exhaust hole on the Bravo, water dumped into the bilge. Boat has thru hull exhausts so this hole was not in use. The exhaust blockoff plate must have been leaking. I was told that to fix it right, pull the engine. I opted for putting silicon into the port hole and luckily it fixed the problem. At least for now...

Re: Water leak in bilge from Bravo 1
 

It sounds like the transom seal. some times you can tighten the nuts up inside ,