red thunder

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.

SSComp

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.

WILDTHING TAZ

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

Reckless32

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...

LLcoolBaja

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!


OK......I think I have a suspect .......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 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.

WILDTHING TAZ

GOOD LUCK

US1 Fountain

iTrader: (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

blue thunder

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

LLcoolBaja

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

HARRISONMIRAGE

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!