broken link on selector, what is its function?

[misterroy]

https://drive.google.com/file/d/1TER...ew?usp=sharing

Hi above the selector there is a thin plastic link, it is broken, what does it do?

It is on a 15 HP Mariner from about 1992.



https://www.crowleymarine.com/mercur...cfm?mdl=EGBTUP
There is a plate on my engine saying
W15ML 684C L 352547 is the above link the correct one?
The broken part is 12.

thanks