How do I change the length of the search results in Wordpress? - Stack Overflow

I have tried using this code to reduce the length of the search results in Wordpress but it doesn't seem to make any difference. It basically posts the full page as a search result rather than just part of the page.

    function custom_excerpt_length( $length ) {
    if (is_search()) {
        return 200;
    }
    else{
        return $length;
    }
}
add_filter( 'excerpt_length', 'custom_excerpt_length', 999 );

I am using the plugin 'Ivory Search' which uses the standard wordpress search result function. Any help would be appreciated.