Sierra 18-7208 float can be modified to work. I think the center hole has to be drilled out and the overall length may need to be shortened. I have one that the previous owner modified. BRP 0302559 looks like it could be modified to work as well.
Search for Poche family outboard. They have a section on basic carburetor repair. At the end of the article they talk about making a new float. They also mention the Sierra float.
Hope this helps.
My first response disappeared.
Rob
