Water leak in bilge from Bravo 1
05-23-2004, 06:45 PM
#1
Guest
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Water leak in bilge from Bravo 1
Long time reader of offshore only, 2nd time post'er. 
Anyhow, I am really stuck
....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.
Anyhow, I am really stuck
....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.
Platinum Member
05-23-2004, 07:08 PM
#3
Charter Member
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.
05-23-2004, 07:41 PM
#5
Guest
Posts: n/a
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!!!
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
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!!!
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
05-23-2004, 07:43 PM
#6
Guest
Posts: n/a
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!!!
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
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!!!
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
05-23-2004, 11:28 PM
#7
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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
05-24-2004, 09:03 AM
#8
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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.
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.
05-24-2004, 06:11 PM
#10
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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
BT
