A picture is worth a 1000 words .... or so they say.
It really might help answer your question. I'm not familiar with your machine. But (I'm guessing now) it's a shuttle machine (?). If so then it's probably like my two New Homes. Both of them have springs that work with the feed dogs as they ride on their cams. I've had to clean, clean, clean, those areas so the dogs don't bind up on their mechanisms.
Joe