This comes from a thread in the general b2evolution questions forum. Since it's a hack I figured I'd put it over here. BTW this is untested. I'm pretty sure it'll work, but I'm also pretty sure the earth is flat and the sun goes around it.

In b2evocore/_class_item.php find:

			{ // We are offering to read more
				$output = $content_parts[0];
				$output .= $before_more .
										'<a href="'.$this->gen_permalink( 'pid', $more_file ).'#more'.$this->ID.'">'.
										$more_link_text.'</a>' .
										$after_more;
			}

Change it to:

			{ // We are offering to read more
				$output = $content_parts[0];
				$output .= $before_more.'<a href="'.$this->gen_permalink( 'pid', $more_file ).'#more'.$this->ID.'" ';
				$output .= 'title="Read full text of '.$this->title.'">'.$more_link_text.'</a>'.$after_more;
			}

I've had hardships sometimes building strings that way, and I never know if I should be using $this-> or $Item->get or whatever else might work.