First set of Fox shocks for me so this may be a stupid question. I just purchased a pair of Fox ski shocks that were last years stock at the dealer. I installed them & it seems to me that they are not charged ot have lost their charge. The compress & stay there. I cranked the springs way up and they still do not rebound unless I lift the front end. Do they not come charged? do they lose their charge while sitting on the shelf?