The earliest map showing the Portuairk area clearly is William Bald's map of 1806, , though Bald does not label the place 'Portuairk'. The site now occupied by the village was part of the Achosnich clachan, as was Sanna. The fields of Portuairk are shown as being worked, but there are no houses marked, so presumably the people who had those fields lived in Achosnich.
By 1856, when the Ordnance Survey's First Series map of Coll was surveyed, the settlement was well established, with six houses marked, four at the eastern end of what is now Portuairk, and two shown on the Sanna side of Sruthan Bhraigh nan Allt - see Diary post about these buildings here. Among those who had settled in the township were the MacColls. 
Portuairk was connected to neighbouring townships by three tracks. The southern followed the line of the present road, and ran to Achosnich, an eastern branch led to Sanna, with a short spur which connected to the small settlement on the other side of Sruthan Bhraigh nan Allt, while the western turned to run south to Grigadale. Although the house at Bay MacNeil, above, had by this time been built, it was connected not to Portuairk but south to a place called the Store House on the present Achosnich-Lighthouse road near Carraig. A link to the 1872 map is here.
The following 6" map, surveyed in 1897, shows little major change except that there are more buildings. The path to the satellite settlement to the east has fallen out of use, and the buildings are marked as roofless, so were no longer occupied.
When Ardnamurchan Estate was broken up in 1948 and various lots sold to private buyers, the Achosnich lands were broken up, with both Portuairk and Sanna sold separately, Portuairk as Lot 53. 
An interactive map of the Portuairk area is here.
Related blog entries:
A Portuairk Satellite Settlement
 Alasdair MacColl, personal communication.
 Ardnamurchan Place Names - Donald MacDiarmid, link here.
 'Ardnamurchan, Annals of the Parish', ISBN 0-9515895-0-41981, 1981.
 1806 Bald map, and 1948 map for the sale of Ardamurchan Estate courtesy Donald Houston of Ardnamurchan Estate.