This picture is from a 75-TS I have. Carb looks the same. I bet you could by a complete 75 for what a new float would cost, if there was one available. There really isn’t much interest in most Martins but after my experience with the one I have I am really impressed with them. Because of age my “I want one” list has gotten a lot smaller but the 100-TS is still on it.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.