EMPLOYEE WAS GREASING A FLOATING PUMP STATION WHEN THE RAFT TIPPED OVER CAUSING THE EMPLOYEE TO STRIKE HIS LIP ON SOME PART OF THE RAFT AND THROWING HIM INTO THE WATER. COUNTER WEIGHTS PREVIOU SLY PLACED ON THE RAFT TO HELP INCREASE PUMPING VOLUME. THESE WEIGHTS CAUSED THE INSTABILITY OF THE RAFT ALLOWING IT TO FLIP EASILY. EMPLOYEE INJURED LIP. NO PROPERTY DAMAGE.