Sewing machine help!

[fieryworld.livejournal.com]

Hey guys, I really need some help with my sewing machine! I've been using my mom's sewing machine for a long time, but I'm not really an expert with troubleshooting and stuff. Well I just got my own sewing machine, it's sort of a vintage one - a Singer 247 from the 70's. Everything works great but there is one problem - the spot where the string wraps around a knob that adjusts the tension - that thing is like too tight. So every time I try to use it, the string just breaks. After wrapping it around that thing, if you just pull on it, it takes a lot of effort to pull it through... even if the tension is set to 0. I think somehow it got messed up and is exerting way too much force. I tried to oil it (I dunno why) but I don't think that helped. Is there some way to fix this or does it need a new part? Thanks!!

X-posted, sorry!