Hi,
The read more setting of the HikaShop configuration will only add the read more button to the product description edition interface.
You still need to add the readmore tag
<hr id="system-readmore" />
(what the readmore button does when you click on it) in the description of the products where you want the system to do the cut. And it will do it automatically on the listing if you select the "image and description" layout in your listing, but for the "image and title" view, it's up to you to add the code. I would recommend to take the code from the "listing_img_desc" view file. It's much more adapted to the listing_img_title that the code from show_default.