@herz84 You can don’t have to hack the code for this. In the dashboard, go to the pages that you have used in the service widget. Look for the ‘Excerpt’ option box. Write you summary there and click on ‘Update’. This summary will only be shown in the service widget, this will help you control the words or sentence.
Thanks for your quick reply, but I’m afraid I can’t follow you. I don’t see any ‘Excerpt option box’ when I’m in the editing mode of a page…? Could you maybe clarify with a screenshot?
If you click on screen options which is located on the top right hand side of your WP dashboard, you will find an option called Excerpts there, which you just tick.