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What is the minimum needed to remove the inner and outer transom plates (shields)?

DavidW2009

Regular Contributor
The manual instructs on how to disassemble every single part. I think it is more than what I need to do.
What are the parts that need to be removed to remove the inner and outer transom plates (shields)?

I've never done this before.

The outdrive and the engine have been removed. (Had good instruction on that)

What's the minimum I have to disassmble to remove the transom mounted stuff? (getting boat ready for a new transom)

Thanks.

Edit: This is for an OMC Cobra 2.3L Ford, 1987
 
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Please don't use that guy's process as your guide. He did everything that an inexperienced back yarder would do and as a result demolished far more than he had to. His repairs assume that the wood does all the structural work and consequently is over thought and over done.
A little research, a few questions asked, and a trip to the public library would have helped immensely.
Were it my project, I'd have cut only the area of the transom where there was actual rot. I'd have filled it in with several layers of (epoxy encapsulated) thin plywood and mat building it up slowly until it was back to original thickness. This way I can control the resin better and not have to try to do a huge piece at one shot. I'd finish it all off with a nice fillet of epoxy putty so that my finishing layers of cloth blend smoothly into the hull without a hard bend at the corner.
To repair the stringers. I'd use 2 inch thick blue foam from the Home Depot which is easy to cut and form. I can stick it in place with spray adhesive or hot glue and be sure it fits perfectly before filleting it in place and covering it with a heavy build up of roving and mat. I would build the stringers at least 3/16th thick and more where they need to carry weight like the engine mounts.
I would add extra cross bracing.

The foam is a perfect way to make forms for the glassing. There are also pre formed parts available from Jamestown Distributors that are foam parts with biaxial roving, matt already on them. You just plop them in place and wet them out.

Don't start out on the wrong foot and end up like the guy with the (now worthless) boat that never gets finished.
 
o2batsea,

Thank you for your comments.

Looking at that thread again, you have a point. The transom was not that bad and apparently most of the foam was still okay. Stringers needed some work, though.

The thread does not cover how to disassemble the OMC transom plates. So apparently, it's not too difficult.
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I'm approaching my project with this philosophy:

Mechanically and electrically the Baretta is very good (it now has 99 hours on the meter and still has the OEM black shift cables). The engine and drive are obsolete OMC, but may be good for another five years, with proper care. I estimate about 30 hours use per year.

The hull is in very good condition. Engine mounts are very good. The trailer is good.

Fix the transom. Sister the stringers. Keep the costs low (no total restorations), keep it in a carport out of the weather, and use the boat for five years, then discard.
 
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With the drive off and the engine out, remove the exhaust pipe from inner transom. Undo the tilt/trim hoses with a (7/16ths?) end wrench (don't lose the baby o rings). Remove two bolts from the water supply pipe and remove pipe. Undo the six nuts on the inside transom shield. Gently pry shield away from transom and set aside. Drive out studs with a brass hammer or wood block. That should free the outer gimbal housing from the boat so you can remove it.
When you reinstall, buy a new rubber foam gasket for the gimbal housing. Very important.

Rotten wood inside of a stringer does not mean the stringer needs to be repaired/replaced as long as the fiberglass covering it still has structural integrity.
To this day, builders of chop gun boats are still unclear on the concept. You will see boats with exposed wood stringers lightly tabbed to the hull. Scary. The glass is supposed to be doing the structural duty, not the wood. The wood is just the form around which the glass is laid. Fully encapsulating the wood with several heavy layers of roving is the way to build. If your boat shows any of the wood with little or no glass covering it, well, let's just hope it isn't that way. If possible to just cut the top off the stringer, dig out the soft wood and glass the top back on, I'd do that. Leave the wood out. If you can't get it out, let it dry for several weeks followed by a generous slosh of mixed epoxy resin thinned 50% with xylene. The wood will drink it up and will harden mushy wood when it sets up. You might be able to repair your transom with this method too.
You can use foam, plywood, cardboard, just about anything that's easy to form and fit to build structural members.
Manufacturers use 2 by wood because it is cheap and easy to work with and doesn't require highly skilled labor.
 
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O2batsea,

Thanks again. I think you let me know pretty much what I needed to know.

I believe I'll have to disconnect the shift cable and the P/S yoke, too.
 
Yes, you have to undo the shift cable, the tilt/trim sender wire, the power steering actuator, and (IIRC) the hose that carries the shift cable inside. I removed the drive and let the tilt pistons droop. In hindsight I should have removed them or figured a way to keep them from flopping since the flexible hose got a bit crimped. No harm, but just bad practice I think.
 
Finally had a nice day, and some free time to remove the transom parts.

Here is a basic outline of how I removed the outdrive and transom parts:

1. Removed the outdrive: (6) locknuts /flat washers and the tilt/trim cylinder shaft (rod ends).
2. Removed the power steering pump without disconnecting the hydraulic lines. Set to one side.
3. Removed the 2.3L Cobra engine (took one hour, simple to remove since the engine does not bolt to the transom parts anywhere). Removed the inner exhaust pipe.
4. Removed (6) nuts and flat washers retaining the transom parts to the transom, from the inside.
5. Removed cotter pin from the power steering yoke clevis pin and removed pin. The transom parts immediately came loose and I could see it would be easy to remove.
6. Lifted the inner transom plate off and set it to one side.
7. Moved the tilt/trim pump into the bilge. (The carpenter ants and termites already disconnected it from the transom for me)
8. Moved the lower shift cable into the bilge.
9. Removed the outer transom parts and set on an old tire right under the transom.
10. Carefully removed the tilt/trim pump and lines, still connected to the cylinders, by lifting thru the key hole and setting on the tire. Lifted the lower shift cable thru the key hole and set on the tire.

I did this all in less than an hour. The only hoses disconnected are the raw water cooling hoses. All hydraulic lines are still connected. No oil dripping anywhere.

It really was way simpler than the manual said it would be.

I do have a question about transom construction: How thick is the fiberglass "skin" of the transom suppose to be?

The total thickness of the transom is 2 1/4". 1 1/2" of that is wood. That means the fiberglass is 3/4" thick. I had no idea the fiberglass would be that thick. Is this standard industry practice? 3/4" thick fiberglass transom?
 
hystat,

I posted a photo of the keyhole in the Boat Project gallery. The 3/4" from the transom outer skin forward is either fiberglass or some kind of composite (non-wood) board that is rock solid.

Reading on another forum, there is a test to perform on the transom to see if it's solid. By lifting up on the outdrive, if the transom is rotted, the transom will flex. I could never get the transom to flex. The whole boat would go up and down and there was no detectable flexing. Now I see why. The main center section is this solid non-wood composite, 3/4" thick. This is a good thing to find. It appears the transom is quite well made, except for what the ants and termites did to it.

I also could find no evidence of water leaking past the transom seal. I'm liking this $400 orphaned boat more and more. (LOL). It looks like it will be worth fixing up (putting limits on costs) and keeping for 5 years or so.
 
Well it doesn't look as bad as all that. If you can get that dead wood off of there and replace it with new (encapsulated) ply you should be good.
To effectively encapsulate the plywood, mix up a batch of (West system, System 3 or MAS) epoxy and thin it 1 to 1 with Xylene. Slosh on as much as the wood will drink in. Let that cure over night and lightly sand. Repeat. This will seal up the wood completely and will let you bond it easily. Cover the repair with two layers of cloth.
 
O2batsea,

Thanks for input on this thread. I may try to fix the transom myself since it's easy to get to (don't have to remove the hull cap).

The engine mounts are quite sturdy and have about 5/8" thickness of fiberglass all around. There are a couple of bad spots in the stringers, but they're surround by good glassed in wood. I have not found any soggy foam yet. Need to look some more, though.
 
I left out one item. That is the steering cable had to be disconnected.

For that chore, I went to the manual (not OMC) and it actually had good instruction on removing the cable, which is not difficult. After that, the power steering pump, cylinder (lines still connected), and the inner transom parts were lifted out of the boat as a sub-assembly.

I also left the interrupt plate attached to the upper shift cable/control module and stored it flat on a large shelf.

I'll start another thread elsewhere on the transom repair, and another thread on the reinstallation of the drive and the engine. And lake testing the results.....and that may be a couple of months. The interior needs to be refurbishhed, too.
 
Your helm is a rack and pinion. It has a gear wheel on the shaft that actuates a geared rack which in turn pushes and pulls a cable. Or it may be the type that uses a spring-wound cable which is meshed with a wheel inside the helm housing. In any case it is a mechanical wire connection from the wheel to the stern drive. Cobras came with a power assist which is merely a hydraulic piston that is used to help make the steering feel lighter, especially under high load conditions (high speed, high horsepower) which would make steering harder without it. When the cable pushes or pulls it opens valves that direct hydraulic pressure to the assist piston. It is not a true hydraulic steering.
Hydraulic steering uses a helm which is a pump. Tubing connects the helm pump to the actuating (steering) cylinder. Turning the wheel pumps fluid towards one side of the actuating piston or the other which turns the drive left or right. There are no cables.
The advantage is that you can get rid of the power steering components bolted to the engine entirely. This will gain you several more horsepower and reduces the plumbing quite a bit.
 
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O2batsea,

Thanks for the explanation. I didn't know about an hydraulic steering application for a small boat.

I'll look it up on the 'net, but this project boat has some strict cost limits. I tried the boat on the lake a couple times last Sept., and the P/S assist works fine. I like it a lot. Steering is effortless. Better than rack and cable on my Bayliner.

I'm not really looking for power. Dependability and fuel economy are important. The 2.3L, from what I read, is economical and should have sufficient power as is. Hydraulic steering would probably improve the economy. You have a point there.
 
o2batsea,

Is hydraulic steering used on outboards?

I have another project after this one. Fitting an old Chrysler to and old tri-hull (haven't bought the hull yet). That project will be a pretty thorough remake of the boat. I may want to use hydraulic steering on that one.
 
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