試す

$('#owner_select').val(id);

http://jsfiddle.net/qWycT/

function select( id ) {
    var select = $( '#owner_select' ),
        option = select.find( 'option' );

    option.each( function( index ) {
        if( $( this ).val() == id ) {
            $( this ).attr( 'selected', 'selected' );
        }
    });

    select = null, 
    option = null;
}