I'm presuming you're a brave quilter with thread painting. Here's my suggestion, mark where the normal tension is on your bobbin case, then turn the screw to the left, just enough to ease the tension and allow the monofilament to ease through a bit easier. Try it for a minute or two, if it's still too tight, loosen just a bit more. Be careful not to pop the screw out it would be a pain in the toukas to get it back in, and probably a trip to the dealer.
Happy quilting!
Teri