Rebuild After Transom Repair

[haulnazz15]

Hey all,

I have recently finished rebuilding the transom of my 76 Mark Twain 200V and had a few questions. I used SeaCast to fix the transom, and it seems to be infinitely stronger than the old transom ever was (not to mention the fact that I made the new transom the full thickness all the way across the back instead of just the center section). Anyway, I am preparing to get the transom plate and bell housing back on and need to know if there is anything I need to be adding/looking for at this point.

The boat has a 233HP/351 Merc, which the 233 is a Pre-Alpha I believe. I have a new cork transom gasket, new anode/cathode + through-hull bolts.
I also got a new gimbal bearing/sleeve. New bellows kit w/exhaust tube also.

One thing that I didn't have was exhaust shutters/flappers in the y-tube. They don't appear to ever have been on there and we've owned the boat for 10-15 years. Anybody think they should be added, happen to know what type to get?

Any other parts that would be good to purchase since the engine is out and everything along the back wall is accessible?

 

[chiefalen]

Re: Rebuild After Transom Repair

My opinion stated here time and again is you don't need any flappers, however there are some advocate reinstalling them.

They are available.

http://www.crowleymarine.com/brp_parts/7087.cfm

The above site sells original oem stuff, and was givin here by Don s.

The above is my own personal opinion and should be construed as such.

 

[Don S]

Re: Rebuild After Transom Repair

http://www.crowleymarine.com/brp_parts/7087.cfm

Uhhhhhh Chief, he says he has a Mercruiser 233. not an OMC stringer.

The Mercruiser PN is 60930 if you want them, I would suggest installing them on your MERCRUISR since you already have it apart.

 

[Fishermark]

Re: Rebuild After Transom Repair

Welcome aboard!

Sounds like you've got things pretty well covered. I agree with Chief and think you will be okay without the flappers - but, like the Chief - that's just my opinion.

You meniton you have "new anode/cathode + through-hull bolts." You did buy the correct bolts for the application I hope. They are a special bolt that the acorn zincs screw onto. They are not made of steel - I THINK they are made of aluminum, but it may be some other alloy. Anyway, they are designed to help protect the transom assembly and will get eaten up before the main metal.

It may not be a bad idea to replace the hydraulic trim lines while everything is easy to get to - can be a bit of a bear to get at after everything is in place.

Good luck!

 

[HT32BSX115]

Re: Rebuild After Transom Repair

Howdy,

I have 3" riser extentions on top of my center-riser manifolds. I also have "flappers" (water shutters) in the Y-pipe........I wouldn't leave home without them!



Regards,


Rick

 

[haulnazz15]

Re: Rebuild After Transom Repair

Yes, the bolts are aluminum or magnesium I believe, with new acorns. The old ones were pretty well done-in. I just wanted to make sure I wasn't going to have any big surprises when trying to reinstall the powerplant. I thought about replacing the lower shift cable, but it seems to be working properly, and may be a bear to change out since I read that they changed the threaded portion somehow.

 

[Don S]

Re: Rebuild After Transom Repair

How are you positioning the new cutout? will it be in the EXACT same place, if not, you have a problem. Was the new transom built to the proper specs? Flatness, thickness, parallellism? If not, you have a problem.
Your comment about the threaded portion of the shift cable being a bear makes me think you are taking a lot of steps without know what, why, or how things really need to be done so it will all work together when you get it back together.

 

[Fishermark]

Re: Rebuild After Transom Repair

Replacing the shift cable is incredibly easy with everything in the position that you now have it. The threaded portion is an easy fix as well - the only "hard" part will be finding the right tap. It needs to be a 1/4X18NPS - (National Pipe Straight). I ended up ordering one online as I couldn't find one locally... but once you have the correct tap you simply tap it out and screw the new cable in from the aft side.

 

[haulnazz15]

Re: Rebuild After Transom Repair

Don S,

As far as everything being smooth on the transom, I was able to keep the outer skin intact during the transom repair, so the bolt holes and transom cutout are like they were from the factory. The transom was made to the same thickness as the factory plywood, however the original was 1.5" in the center between the stringers and 3/4" to the sides. I made it 1.5" all of the way across since it posed no interference with fuel tank or trim pump/batteries. I don't see why you would think something was wrong with it anyhow.

The reason I know the left-middle hole on the gimbal housing needs to be rethreaded is because I tried to thread the bolts in by hand after I got the unit repaired at a marine shop (one of the bolts broke off while originally dismantling).

I made the comment about the shift cable being a bear is because I had heard that it required a bit of work as opposed to just using the cable as-is. We had an issue of the drive not going into forward gear right before we decided to do the transom repair, so I didn't know if it was out of adjustment somewhere in the linkage or if it was the lower shift cable. I didn't see anything wron with the lower shift cable, and it seems to slide freely.

I'm pretty good with tools and most moderate engine mechanics, but I don't have a wealth of knowledge about the specifics of outdrives. I didn't how anything worked (aside from in theory) behind the engine of an I/O until I did the transom repair.

Here's a pic of the boat as it sits:

 

[Fishermark]

Re: Rebuild After Transom Repair

Looks nice. One thing you might want to do is install the outer assembly and see if your tiller arm will turn all the way left and right without hitting your new inner repair area. I had my transom professionally rebuilt and it came out looking just like yours. My old transom had a rounded area ground out where the tiller arm comes through - I had to do dome grinding on mine to get the proper amount of travel. Then repaint or coat well to avoid future rot.

Just something to check.

 

[haulnazz15]

Re: Rebuild After Transom Repair

Actually Fishermark, I have already bolted up everything once minus the hole that needs rethreading and checked the steering travel and shaved the areas slightly to allow full travel, but that is excellent advise for those who may be reading this post. I noted the factory notches they had cut out before we tore everything apart. The lower lip had to be beveled as well to allow access to put the exhaust bolts back in.

These pics were taken just after we did the SeaCast back in September or so, I have since cleaned up all of the excess on the outside, as well as replaced the drivers side engine stringer. Hopefully once I get the exhaust flappers and possibly a new lower shift cable, I'll be ready to put the engine back in.