Water coming in via transom - 1992 OMC 5.0L Cobra

[johnbo]

Hi,

I'm trying to help a buddy with his 1992 Reinell with a OMC 5.0L with a Cobra drive. Finally fixed all of the secondary problems associated with a rusted out steel fuel tank and got the boat back in the water today. Found out that we had two problems, a steady stream of water coming in via the transom, and broken bilge pump.

With a limited amount of time to inspect the transom (see bilge pump above), we found a pretty good stream of water coming from the hole on the lower reinforcing plate (wide U shaped piece at the base of the transom mount). We are pretty sure that the water is not coming directly from that area but dribbling down from somewhere. The stream was probably enough to fill a coffee cup in 15 seconds or so. As the water level was within a couple of inches of the oil pan, we returned to the ramp and pulled the boat out of the water.

From the outside of the boat, the bellows look reasonable (I know that this means nothing). The boat has had some lax maintainence in the past, but everything is very clean.

Any one have any thoughts on where a likely source of water intrusion would be?

This problem was noticed (but forgotten) last season when the fuel tank gave up. I checked the outdrive oil this spring for him, and the fliud at the bottom of the drive was pure gear oil, no water.

Second, as I fully expect the answer to be that we need to pull the outdrive. Can anyone give me a rough comparison of the differences between pulling this type of drive along with the replacement of bellows, etc, and the same type of job that I recently did with by '94 Volvo SX drive?

I have the factory shop manuals for my Volvo and he has a Seloc (I gave it to him after getting the Volvo manuals). I'd like to avoid convincing him to buy a set for the OMC, but I think that I hear this coming as well. However, time is pretty short (combined multi family vacation coming up) and I want to get started in the next day or so with pulling the drive.

Thanks in advance,

johnbo

 

[lrlima]

Re: Water coming in via transom - 1992 OMC 5.0L Cobra

To me it sounds like the ujoint bellows is leaking. And you're right, you will need to pull the drive. Regarding the comparison with the Volvo...not sure. The problem with water in the bellows is that it usually kills your ujoints and gimbal bearing.

 

[Don S]

Re: Water coming in via transom - 1992 OMC 5.0L Cobra

Assuming the "Reinforcing Plate" is the one pictured below.

The hole is to allow water to run out of the cavity created by the transom shield. Otherwise water would lay on the transom and rot the plywood.
Water coming in there could be from the transom sheild seal, or most likely the exhaust Y connection. I have replaced many exhaust Y's that corrode or break around the bottom 2 attaching bolts. If the engine was removed to replace the fuel tank, it's very possible the Y pipe got banged into during the removal or install of the engine, which could break the pipe.

 

[johnbo]

Re: Water coming in via transom - 1992 OMC 5.0L Cobra

Don (and others),

That is the right part, and the reason for the hole makes sense. Fortunately or unfortunately, the water leak existed before the fuel tank episode, from approximately the same spot. I don't think that the engine was removed for the fuel tank repair. They appeared to cut a big hole in the floor to gain access.

How likely is corrodison (I can't spell this morning) on a fresh water only boat with about 180 hours on it. My buddy is the original owner, and says that the boat has never spent more that a day or two in the water at a time.

However, thinking about this, the lower leg was replaced in around 1993/1994 when he hit a submerged stump. I guess that it is possible that a crack was formed then and its taken a number of years for it to fester.

Is there any way to test for this without pulling the engine? I can just see the drainage hole in the bracket. Can't seem to get enough access even with a mirror to see the bolts on the Y-pipe.

Thanks,

johnbo

 

[Don S]

Re: Water coming in via transom - 1992 OMC 5.0L Cobra

I pull engines all the time, put the drives back on and stick them back in the water to find the leaks.

There is a leak, and it has to be fixed. No matter what the problem is. And if it's at the lower part of the transom shield, it's time to go to work.

 

[wsparadise]

Re: Water coming in via transom - 1992 OMC 5.0L Cobra

I had a leak and while I hoped it was the bellows, turned out to be the seal between the transom mount and the transom. Had to have the engine pulled to re-seal the boat. While it was expensive ($1300) as they had to pull the motor, it was worth every penny as now it is completely water tight and I dont have to worry about it. When I think of this as insurance to protect my investment not to mention safety for those who go boating with me, it was a small price to pay (even though it hurt a little). I am not saying this is your problem. It could just be the bellows. I recommend having an experienced mechanic check it out. I understand one can put water in the bilge (with the drain plug in) and check for this transom seal leak. I have not done it and I would think you would want to be care full not to put enough water in to reach the motor or starter.

I am not a mechanic so consider the above opinions and not advice.

Good luck.

 

[billieand]

Re: Water coming in via transom - 1992 OMC 5.0L Cobra

i think iam having this problem,my machenic said something about this exhaust deal,and i did just rebuild the engine ,took it in /out,how can i pin point this problem,,mine is a 91 omc 3.0,how can i check to see if it the shift cable,bellows,ect,,thanks,,billie

 

[bruceb58]

Re: Water coming in via transom - 1992 OMC 5.0L Cobra

I suggest you post your question with a brand new post. Adding it to the end of a 2 year old thread is going to make it harder for people to help you.