Troubleshooting Transom Water Leak

[holgo123]

I have a 1993 OMC Cobra 5.0 L in a Chris Craft Concept 217 BR. I had some water intrusion (previous post, "Topic: 1993 OMC Cobra 5.0 L EFI Water in Oil, on top of Piston... ") I have the engine running and am now trying to troubleshoot the water leak I found directly at the bottom of the transom bracket. There was a steady stream of water coming out after I got the engine running while sitting on the trailer at the boat ramp. The water was flowing right in the middle of the transom right above the drain plug hole. It looks like it is coming out of a hole right at the bottom of the bracket. I didn't see the hole until I got home and started looking around with a mirror. I can get to the hole and put my finger in it, I can't tell what it is for... I have pulled the drive off and there isn't any water in the u-joint bellows. It is bone dry... The transom seems very solid. I have drilled into it while mounting trim tabs and other accessories. It is nice, clean, wood. It didn't seem like the water started flowing until I had the engine running. I din't hear or see anything at first while I was sitting there trying to get up the nerve to turn the key. I wish I had looked before I got the engine running, but after I had the engine cranked and turned it off, you could hear the water trickling a little. Now that I have the drive off, I can't go back to the boat ramp... All the nuts seem snug and tight on the bracket itself. There is no play/movement anywhere... I have also pulled off one elbow and looked at the flapper. It looks kind of old and dirty... It doesn't cover the entire hole when closed, but I am guessing they are not designed to be entirely water tight when closed. Are they? <br /><br />I want to try a couple of things:<br /><br /> - Can I seal off the exhaust where the bellows attach and fill the exhaust Y pipe up with water to see if it leaks inside?<br /><br /> - what is that hole for in the bottom of the bracket? <br /><br /> - what are the chances that the shift cable hose is leaking? I can't see it from where it attaches to the transom bracket...<br /><br /> - can I put something over the u-joint bellows and back the boat in the water to check for a leak whaile the boat is just sitting there? <br /><br />Thanks for any advice...

 

[lilmandavis]

Re: Troubleshooting Transom Water Leak

is the water passing through from the bilge or, is the water only comming out of it while the engine is running? on my cobra the whole botton of every rib on the bellows is cut off. so there would be lots of water passing through there. thats how they come new.

 

[holgo123]

Re: Troubleshooting Transom Water Leak

Water is leaking from either through the transom or leaking from something else in the transom plate area. The water is flowing directly in the middle of the transom plate on the inside of the boat in the bilge area.

 

[holgo123]

Re: Troubleshooting Transom Water Leak

I am doing some more troubleshooting and pulled off the drive water pump and the impeller is missing a chunk of one of the blade and several others are cracked...

 

[rebars1]

Re: Troubleshooting Transom Water Leak

Is it a hole in the "T" connector between the Y-pipes and the inner transom plate? Your idea of sealing the exhaust exit and filling the y-pipes could work if you use something like a plumbers pipe sealer and plugged it in front of the exhaust bellows.

 

[holgo123]

Re: Troubleshooting Transom Water Leak

It is a hole in the bracket itself between the two lower mounting holes for the transom plate. I am going to take a piece of rubber or vinyl and hose clamp it over the exhaust on the rear of the transom and put some water in the y-pipe... If there is a hole, it should leak out... If that doesn't leak, I am going to seal up the drive shaft hole, the exhaust hole, and the water inlet hose and back the boat in to the water on the boat ramp... I am going to see of the leak appears... If no leak... I'll remove the water inlet temporary cover and try again, If no leak, I'll remove the exhaust temporary cover and try again. If no leak, I am not sure what the next step should be...

 

[lilmandavis]

Re: Troubleshooting Transom Water Leak

let us know what happens. im curious. you need to find where that chunk of impeller is also!!! thats another problem waiting to happen.

 

[rebars1]

Re: Troubleshooting Transom Water Leak

It might be the shift cable boot leaking, or the seal where the trim hose connection from inside to outside the boat.

 

[holgo123]

Re: Troubleshooting Transom Water Leak

I sealed off the exhaust hole in the transom and filled the y-pipe with water... no leak. I went ahead and sealed off the bellows/shaft hole and shift cable hole and water coolant hose and am going to go down to the boat ramp tomorrow and experiment... We will see...

 

[holgo123]

Re: Troubleshooting Transom Water Leak

Well, I am bummed out... I sealed up the exhaust, bellows/driveshaft hole, shift cable, and water coolant line. I backed in to the water and voila... water started leaking in through the transom right below the exhaust running over the bottom of the transom bracket. I only had to back in enough to bring the water line 3 - 4 inches up the transom mount for the leak to start. I looked at the mount and noticed the you can run a piece of paper between the transom and transom mount on the right bottom for about 4-5 inches (a real small gap)... If the seal runs the circumference of the transom mount, it seems like some may be missing. I guess my only choice is to pull the engine and take everything apart. <br /><br />Does anyone know of a source for a transom mount. The one on my boat had some corrosion on it from the previous owner to the point of some of the metal becoming brittle and corroded away. If I am going to have to take it off, I would like to replace it. I am just hoping I don't find some bad wood. Any advice/thoughts would be appreciated. Any maintenance I should do while having the engine out and transom apart?

 

[Bt Doctur]

Re: Troubleshooting Transom Water Leak

did a cobra that had a similiar issue. hit some rock and took out the prop,developed a leak. determined that he dislodged the transom enough to slip a business card under the edge of the housing.pull it apart, replace the transom gasket and no more leak