I encountered a bad problem with the text length that has been a regular problem for me in a number of cart areas.
The problem is that the settings in admin are not being applied and changes to the database are not working, eg: set the text length field to 0 (ie: turn it off) and nothing happens - the change is completely ignored.
If this is affecting your full product listings page you can kill the product description by amending the tpl_modules_products_all_listing.php file.
Open the file and find the following:
if (PRODUCT_ALL_LIST_DESCRIPTION > '0') {
$disp_text = zen_get_products_description($products_all->fields['products_id']);
$disp_text = zen_clean_html($disp_text);
...and amend it to:
if (PRODUCT_ALL_LIST_DESCRIPTION > '0') {
$disp_text = zen_get_products_description($products_all->fields['products_id']);
$disp_text = zen_clean_html();
Don't forget that the amended file should be uploaded to your custom_template (overides) folder.