John (Johan) born 10 Febr. 1845 in Ärtemark parish, Älvsborg county. Father Johannes Jansson, mother Cajsa Olsdotter.
the old Swedish patronymicon system meant John got surname Johannesson (or shorter Johansson)
Source: Ärtemark C:4 (book of births) pg 29, (GID 719.6.23500) GID = Genline Id Nbr. comes from the churrch records online at www.genline.com
Suggest you put a new item to Älvsborg county asking for EMIBAS lookup - can also be put to General board, if you wish. EMIBAS is emigrant records on CD. If you have name and DOB and parish for birth it is a rather good chance someone can find it for you, thus you get the date when he left home parish. I have not searched for his wife yet.