I agree with Cari and RotaryQueen. You might want to check
https://archaicarcane.com/singerattheraces/ I think she also has a link on that page to another page about cleaning the foot controller. A youtube link
https://www.youtube.com/watch?v=YgTnzs1U4aA I know that after watching another
https://www.youtube.com/watch?v=YgTnzs1U4aA I know that after watching a different one from "Featherweight Shop" about a hook assembly, I had a little more confidence to fix a different problem I had with a FW.
Janey - Neat people never make the exciting discoveries I do.