What was found
PRIOR TO ADDING POWER FOR TAKEOFF, OUTBOARD SPOILERS SPONTANEOUSLY RETRACTED ASSOCIATED INDICATIONS INCLUDED ROLL OUTBD LIGHT EXTINGUISHED (GLARESHIELD) AND MASTER CAUTION & ROLL SPLR OUTBD GND CAUTION ILLUMINATED. PILOT VISUALLY CONFIRMED THAT INBOARD SPOILERS DEPLOYED WHILE OUTBOARD SPOILERS RETRACTED. ABORTED TAKEOFF AND RETURNED TO THE GATE. REPLACED RIGHT HAND SIDE LIFT DUMP VALVES (OUTBOARD) IAW AMM 27-62-01-000/400-801. PERFORMED OPS TEST OF THE GROUND SPOILER SYSTEM IAW AMM 27-62-00-710-801. OPS TEST PASSED. RETURNED TO SERVICE.