(Olympia, WA)  --  Officials are trying to find out what caused a mechanical malfunction that led to the seven-hour shutdown of the State Route 104 Hood Canal Bridge in Washington.  The span was closed around 8:17 yesterday morning after it was raised to allow marine traffic through, then got stuck.  The state transportation department told KING-5 that engineers were able to lower the span manually by around 2:30 p.m., then reinstalled a piece of equipment that was removed during the lowering process.