I stepped on this and broke it yesterday, it's the bracket that sits underneath the floats, clipped over the main jet. I can see it on the parts diagrams but there's no listing or part number for it. WTH?
Still a success story, my 74 550 was only running on 3 cylinders, found out number 4 wasn't getting any gas so after replacing the float needle and seat it runs perfect. I put the broken bracket (tang???) back anyway as it still stayed in place but it's obviously not correct.
Anyone know where I can get one?