I try to only do operational checks when the machine is fully cleaned and lubed this is the only way to tell if it's having issues. If your cleaner of choice is degreaser that works.
The SM3 do work without the spring. It will be suboptimal, loud, and not smooth. Other machines won't work correctly without it. The Olympia SF needs its silent return spring set correctly for the machine to work right.
Park the drawstring, nix one stop, deal with a fiddly bit, and then pick up a set of captive bearings... Man, it can't get simpler than that! (Also, a silent return on American typewriters would have spoiled everything for Leroy Anderson, so thank Heaven that it did not happen! 🤣)
