Temp sensor for idle advance? Part of perhaps a bigger part? Looks like it might expand and contract with heat. The 246GT uses a similar, although smaller, part to do the same job on US cars. D And, I think we should name it . . . Peter. After all, it looks like a capital "P"
Actually this was a test, which I failed. I have it in my photos when I removed my carbs. I am pretty sure it is not inside the carb as the photo before is all the carbs un molested, and after taking 8 or so apart I would remember that.. I took the picture because it was important and I remember, boy I am glad that is not broken. I vaguely remember it slipped inside something a rubber piece?? and it was about the size of a quarter. I know I am losing my memory but this is driving me crazy!
Could it be on the throttle linkage to hold the ball/socket together, ie a round cotter as Troy mentioned? Here's the version on the 550, but it has a straight bit coming off at 90 degrees to the circular part, and the straight bit goes inside the socket and holds the ball in. Perhaps the thing you have is similar......but different? Image Unavailable, Please Login
The part of the grenade you don't throw away. (If it's associated with the carbs, I'd guess a rotational return spring of some kind.)
spring inside the rear view mirror? "prismatic rear view mirror tab spring" (maybe should be 2 of them?)