Clam shell thru hull leak

fishkeeper59

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Oct 24, 2010
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Hello all,i finally have gotten my thunderbird t19c on the water after alot of repairs done to the motor and tilt and trim system and all the little things that went wrong during the time thay it sat uncovered, I do have a problem that I cant seem to figure out,the steering that goes thru the stern has a leak,its a clam shell will a wooden ball and a O ring, I have replaced the O ring,but there is no place where the O ring would sit,therefore when you steer the water would leak into the bilge at an alarming rate,has anyone solve or ran to this problem,just to update the boat is a 75 thunderbird cathedral hull.other than the leak, the straight 6 OMC motor runs great. Any help would be very much appreciated. Thank u.
 

southkogs

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Re: Clam shell thru hull leak

I think what you're describing is this kind of steering:
OMC_Steering.jpg

If that's the case, your first problem is the "ball" - that mug ain't supposed to be wood! If you don't have the original cable with the brass ball (and can't find one), you have to buy an adapter kit with the ball. The O ring sits on the inside of the clamshell, but really forms to the outside of the "ball." I'm assuming that the wood ball wasn't formed quite right, and isn't maintaining enough pressure on the ring to make it work right (just guessing though).

The adapter I mentioned can be purchased here: http://www.boatingsolutions.com/OMCTT-Thru-Transom-Steering-Cable-Adapter-P6547C1383.aspx There's also a brass one available (can't find the link right now), or you can sometimes find the correct steering cable on eBay.
 

fishkeeper59

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Re: Clam shell thru hull leak

Thanks for the reply Southkogs,i might be mistaken in regards to the material,it could possibly be brass but has the color or wood,i did purchase a new O ring,the steering cable is original and the last owner just put a whole lot of silicon on it,now you said the o ring sits inside but in front of the ball,but when I steer the ball moves forward and back and it thats when water gets in,and it is exactly the picture you posted, I have applied some silicone to front and back of clam shell and still leaks but not as much,i just dont understand the concept of habing a steering cable thru the transom and under the water line,the adapter you posted is really expensive,is there any other way I can seal this leak. Again thank u for sharing your knowledge.
 

southkogs

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Re: Clam shell thru hull leak

Yours (and mine) is an old steering rig - I'm not even sure how long they lasted. OMC started putting the TruCourse steering system on around '73 and it's MUCH better - in fact, a very good system actually. Everything happens inside the boat.

Okay, check a couple of things on your assembly. Start by making sure the four bolts that hold it to the transom are good and tight. They go all the way through the transom and should have a nut inside. If that is all tight, and that ball is moving while you're steering, we probably need to make sure we know what that ball is. When that whole assembly is closed up properly, that ball can't move. The O ring essentially pushes up into the seam around the circumference of the ball effectively acting as an internal seal.

Don't use silicone there. Grab some real live marine sealant (Wallymart even has it) and put that one all around the seam of the assembly. Mine sealed up real nice when I did that this year, and I've had no real problem with it.

I'm going to look for a couple images tonight. Stay tuned.
 

fishkeeper59

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Re: Clam shell thru hull leak

Thanks for coming back at me,all bolts go all the way thru and nuts are nice and tight,the ball is made of brass and brand new o ring in place,what I did today was turn out drive all the way to starboard side so that the o ring was plush against the opening and the ball pushing on it,wrapped some rope on the steering cable from the inside to hold it to that position and applied marine silicone on the gaps that the ball leaves out,i let dry for a few hours and tested the pliability of silicone to make sure there are no rips,hopefully this will hold and minimize my leak.send me what images u have when you find them. Thank you very much for all ur input,the boat has been a project for a year now and it really runs well,except for when I opened her up to about 2500 rpm that I noticed my temp go up close to 200 degrees,i think maybe the part where the hose bib goes came out of the water and caused my temp to come up,i will try again in a few days and see what happens. As of right now I am looking into cleaning my carb.ok hope to hear from u soon......
 

southkogs

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Re: Clam shell thru hull leak

Groan ... I didn't take one of the photo's I was thinking of. I knew my manual didn't have the steering set in it but I couldn't remember if the original helm paperwork did ... nope. Sorry no pics on this end.

Are you putting silicone in with the ball? That shouldn't work out. That ball should move quite a bit through the full range of motion. Maybe better if you pop a couple shots of your setup from the outside of the hull.

I'm glad to help what little I can (I'm not all that brainy about it all). I have a '72 with an inline 6 and the electric shift outdrive. I would have thought yours should be the hydro-mechanical shift, but I thought all of those were Tru-Course Steering.
 

fishkeeper59

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Re: Clam shell thru hull leak

Ok, I will take pics.tomorrow,yes there is silicone with the ball. I guess I cant see it working any other way. with the movement of the ball in the clam shell and the o ring just sitting on the ball leaves alot of room for water to be able to come in. when I first took it apart, the previous owner had twine and googob of silicon in the inside part of the transom,i thought I could kinda understand what he was trying to do,and yes there was an o ring in there as well. Any what a dumb idea to have the steering placed below the water line, if they had just designed 4 to 5 inches higher it would never get wet. Go figure? Will post pics. Tomorrow thanks for your help.
 

southkogs

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Re: Clam shell thru hull leak

Just looked at another thread of yours ... You've got the same engine as I do (Chevy Inline 6). Is your drive electric or hydro-mechanical shift? I'm wondering if you don't have an older drive than you think you do.

BTW - did you download the manuals in your other thread? I actually think that one in the link is better than the one I bought online.
 

fishkeeper59

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Re: Clam shell thru hull leak

Hi, I believe its electric,at least thats what I was told by the mechanic that worked on my trim motor. I was able to purchase an OMC manual from one of the guys here on iboats,but unfortunately my mechanic has it at his shop and have been having a problem connecting with him.the manual is really good,very informative and the illustrations are excellent,hope to get it back this weekend.yes my motor is the 165hp inline 6,its a great motor and I will looking thru the forum on whats thw proper way to paint the exhaust manifold and then the motor itself. Can you psost a pic of yours for inspiration. I will take pics. Today and post whay I have been doing on the boat and motor.
 

southkogs

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Re: Clam shell thru hull leak

If your shifter looks like this then it's definately electric:
ElectricShift.jpg

Better if you can verify by finding the actual shift wires (just below the soleniods on the starboard side) at the back of the engine coming out of the intermediate.

My manifold is just good ole' fashioned Chevy block blue. The original owner of this boat treated it like it was another child and the I6 was in really nice shape. Used, but mostly clean. I'll have to get a couple shots of the engine when I dig back into it - but I don't have any right now. This thread has a couple shots of my boat: http://forums.iboats.com/showthread.php?t=507096
 

fishkeeper59

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Re: Clam shell thru hull leak

I took a whole bunch of pictures,but I wasnt able to post,how do you post pic. Anyway according to my mechanic that its definately a electric shift,thru course steering,but uses morse cables.
 

southkogs

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Re: Clam shell thru hull leak

I took a whole bunch of pictures,but I wasnt able to post,how do you post pic. Anyway according to my mechanic that its definately a electric shift,thru course steering,but uses morse cables.

Interesting. Tru-Course Steering shouldn't use the through transom cable. Sumptn' sounds a bit funky. Here's how you post pictures:http://forums.iboats.com/showthread.php?t=468676
 

fishkeeper59

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Re: Clam shell thru hull leak

Here are the 2 area I was talking about,sorry im still new at posting pics.
 

southkogs

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Re: Clam shell thru hull leak

Sorry man, the system "wigs" out on attachments sometimes - I forgot to mention that. Make sure you're replying using ADVANCED when you attach photos.
 

southkogs

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Re: Clam shell thru hull leak

Sorry - I still can't see 'em. I'm maybe PM one of the "ball" to me and see if we can get it that way.
 

fishkeeper59

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Re: Clam shell thru hull leak

Ok, update on the leak,cleaned out all silicone and flex seal,started over with O ring,created 2, rubber gaskets from pond liner material.1st gasket fit exactly around the clamshell inside mount,sealed with 2 ply of flex seal,2nd gasket same exact size of clamshell,treated both with rubber expander and finally silicone perimeter of clamshell,will put it in the water tomorrow. Hope it works.everything looks good so wish me luck.
 
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