I’m so sorry for that oversight on my part, Michael! I should have spotted that mistake in my own testing.
To fix, we’re going to look at the following part of the code as a whole:
<?php if ( is_search() ) : // Only display Excerpts for Search ?>
<div class="entry-summary">
<?php the_excerpt(); ?>
</div><!-- .entry-summary -->
<?php else : ?>
<div class="entry-content clear">
<?php the_excerpt( __( 'Continue reading <span class="meta-nav">→</span>', 'ryu' ) ); ?>
<?php
wp_link_pages( array(
'before' => '<div class="page-links"><span class="page-links-title">' . __( 'Pages:', 'ryu' ) . '</span>',
'after' => '</div>',
'link_before' => '<span>',
'link_after' => '</span>',
) );
?>
</div><!-- .entry-content -->
<?php endif; ?>
The above code is using a conditional tag to detect when a page is a search page and using the the_excerpt() to display an excerpt in that case. It is using the the_content() function in all other cases.
To switch this around, we can use the is_single() conditional tag with the_content() and display the_excerpt() in all other cases:
<?php if ( is_single() ) : // Only display full content on single posts ?>
<div class="entry-content clear">
<?php the_content( __( 'Continue reading <span class="meta-nav">→</span>', 'ryu' ) ); ?>
<?php
wp_link_pages( array(
'before' => '<div class="page-links"><span class="page-links-title">' . __( 'Pages:', 'ryu' ) . '</span>',
'after' => '</div>',
'link_before' => '<span>',
'link_after' => '</span>',
) );
?>
</div><!-- .entry-content -->
<?php else : ?>
<div class="entry-summary">
<?php the_excerpt(); ?>
</div><!-- .entry-summary -->
<?php endif; ?>
Let me know how you get on with that above! I’ll be happy to help if questions come up.