The broken piece of the spring is most likely in the slot on the shaft. Try a piece of metal the same thickness of the spring and tap it with ( gently ) a hammer to push the old piece out .
I had to work on mine for a bit to get the piece out. Not the easiest place to get to with the manifold installed. I tried a small hacksaw blade, but didn't want to mess up the slot, so resorted to a small punch and hammer.
