Helen, If you don't know the names of their children how do you know they are your ancestors?
Have you traced back to them from your known family, or are you using someone else's tree? You are missing most of the fun of genealogy if you don't research for yourself - back one generation at a time from a known event such as your grandparents' death/marriage/birth certs, then find their parents' details from the information given there, etc. etc.

I think you have your marriage date wrong. Maughold parish register records have: William Looney & Dorothy Joughen married 19 Feb 1799. Dorothy had father's consent, which means that she was under the age of 21.

Most of their children were born in Ramsey. See the IGI under Familysearch.org.
- But first check the more recent generations as described above, to be sure you are not looking for the wrong people.

Sue