Replacing scupper tubes

Greg,
There is a tool specificaly designed for these brass (I assume) tubes. I did not know it at the time and made my own 'tool' for my little skiff. I used a roughly 8" long piece of 5/8" threaded rod and a couple of large outside diameter heavy steel washers with two 5/8" threaded nuts. Set the tube in place 'dry' and mark it about 3/16" longer than the actual transom thickness. I then removed the tube and covered it with 4200 sealant and reinstalled it from the outside. Next I put one nut and one washer on the threaded rod and inserted the rod through the tube from the outside. Next I put a washer and a nut on the threaded rod and began to tighten it. Being careful to not overtighten the rod, I checked the new flare until it was tight against the inside of the transom. Worked great and has been leak free for abut five years now.

If you really want to protect the transom I'd suggest coating the transom holes with epoxy first. This way in the event the sealant fails in the future, the expoxy would not expose the wood in the transom.

Hope this helps.

Greg,
I see no problem with the 5200 for the tubes, as I doubt you plan on swapping them out anytime soon.

With regard to the epoxy coating, I was taught this method years ago and never forgot it. Any wood core (transom, bulkhead, hull sides) should be coated with epoxy.

Last but not least, welcome to the site!

I have the Mohler flare tool used to form the flare on the one side. I can loan it to you but I would like to get it back. I replace mine last spring. I used a small sharp chisel to start a split down the length of the tube. Then I just pushed it out with a dowel rod. I did coat the inside of the hole with either 4200 or 5200 and inserted the new tube. The tube seemed to be just a bit short to form the full flare but I just filled the edge with more sealant.
While your at it, run a bead of 4000 along the aluminum corner trim along the length of the transom to prevent water intusion into the core.

I also have a tool I purchased online. Where are you located? I'm in Virginia. I'd be willing to loan it to you. Works great!

Glad to see it worked out for you. I realize my directions were a little sketchy, but I guess you are better at visualizing than I am at typing.