Custom Fields Not in Search Results

You can use an custom plugin for your custom fields

function fb_custom_search_where($where) {
    // put the custom fields into an array
    $customs = array('custom_field1', 'custom_field2', 'custom_field3');

    foreach( $customs as $custom ) {
    $query .= " OR (";
    $query .= "( m.meta_key = '$custom' )";
    $query .= " AND ( m.meta_value  LIKE '{$n}{$term}{$n}' )";
        $query .= ")";
    }

    $where = " AND ({$query}) AND ($wpdb->posts.post_status="publish") ";
    return($where);
}
add_filter( 'posts_where', 'fb_custom_search_where' );

Also you can check the plugin WP Custom Fields Search and you have adhoc an solution.