How to get custom post type title, excerpt, thumbnail and permalink by post ID?

You’re very close. There are a couple things you can do differently to get a better result and at the same time retrieve the excerpt.

We’re going to use setup_postdata to allow us to use functions like the_title() and the_excerpt(). After you finish retrieving and displaying this content, you always want to get back to where you started, so you call wp_reset_postdata() to return to the previous content.

<?php
$post_17 = get_post(17);
if ( $post_17 ):
    setup_postdata($post_17);
    ?>
    <span id="chty_17">
        <dt><?php the_title(); ?></dt>
        <dd>
            <?php the_post_thumbnail(); ?>
            <h2><?php the_title(); ?></h2>
            <?php the_excerpt(); ?>
            <p><a class="more" href="https://wordpress.stackexchange.com/questions/184118/<?php the_permalink();?>">Find out more &raquo;</a></p>
        </dd>
    </span>
    <?php
    wp_reset_postdata();
endif;
?>

It’s important to note that the_excerpt() appends a more link to the end of your excerpt content. Using the above code will output “more” links twice. You can modify this link content using the get_the_excerpt filter.