Hi MaxGara, I agree that according to the parts list, P/N 262664 is the governor spring for your engine, and where you have shown it attaching appears to be correct according to the tech manual (see below).
Here is a drawing from B&S 270962, the single cylinder L-Head tech manual:
![[Linked Image]](https://www.outdoorking-forum.com.au/forum/uploads/usergals/2011/12/full-2772-4569-bs_lms_carb_linkage.jpg)
This LMS carburetor is correct for your engine type according to the manual. Looking at the text it appears that the "return" spring is simply the spring that opens the choke when you set the control for open. There are two versions: one that has an external tension spring, and one that has an internal (on the choke shaft) torsion spring. Your engine has the external tension spring, and it is already installed on your carburetor. I have circled what I believe to be it, in yellow: