Singer Merrit 4525 nesting
I usually fiddle with the Kenmore machines but this fell in my lap.
I have cleaned and oiled.
Sews great then suddenly i get nesting on the bottom. I have removed the tensioner, cleaned and inspected. Reinstall adjusted. Still the thread binds in the discs coming out of the tensioner somehow but not all the time. I have changed the spring/discs but it still happens.
I want to fix this issue before I donate it to someone.