I found a photo archived on Google. It appears the outer baffle tube is bonded at the top of the tube and is only friction fit at the bottom where the slots are cut out. The inner tube is bonded on the bottom at the exhaust exit. If I was going to repair the outer tube I would cut at the "bubble" on top to gain access. If I was bonding the inner tube I would cut around the bottom vent. I am going to try using a snake through the intake openings and see if I can get the outer baffle to move around. Other than that it appears to be a guess which tube is loose. Is one baffle tube more likely than the other to be loose? I assume the boat has back fired at some point. That hasn't been a problem I've had, but it is a 26 year old boat. Any suggestions or advice is appreciated. 

The first pic is of the inner tube baffle and muffler exhaust outlet separated. The second photo is of the two fit together. Not a straight pipe. It takes a turn. Not surprising the way the bubble and the exhaust outlet line up. But interesting in that the manufacturer did not make the assembly as one piece. Maybe an intentional thing so It would give way and not be "bomb like" under pressure? When I had first repaired the joint I was surprised at how little material there was right at that joint. Looking at where the inner baffle tube joins it is obvious that there wasn't much material bonding the joint. Just that little sliver of glass that remained in the exhaust outlet. That will change :)  The third photo looks in at the bubble on the top and the outer baffle. I recognize that many of you have different age boats, different styles of muffler and probably a lot better idea of what I would find inside. But I hope anyone with a similar issue finds the newly posted photos and has a great time playing with epoxy!