Follow Vid's guide on how to best tackle this if you haven't done it before.
http://pinside.com/pinball/forum/topic/vids-guide-to-upgradingrebuilding-flippers
Even though you have only had it for 2 weeks, I'll bet whomever you got the machine from did not rebuild them. Likely culprit is either your sleeves or bushings. Springs could also be an issue. Always good to rebuild your flippers ever so often.
Welcome to the world of pinball ownership! These "relics" need help staying alive.