strip em, refill with oil... (get manual off www. first obviously) and retest... or sack it off and get a new / sale / second hand pair with a better pair for jumping.
Maz dirtjumpers my first recommendation - cheap, solid and heavy..
ensure your disc brakes have the same comaptability (post mount or IS standard fixing?)
BTW, it's a fork not a shock... and what is it?
more pics plz