Zelda Classic Controler

When playing Zelda with a classic controller Link doesn't run properly it's as if the classic stick is not sensitive enough to make him run, he only walks occasionally breaking into a run only to stop when there is a slight change in direction. Works beautifully with Mario though as well as others. Not sure if this is a bug or where to find help with this, is it my my controller? he runs perfectly when using nunchuck stick. Any help would be great. Many thanks )