Where did you get the primer? I have an installation drawing for a Lukenheimer D-4010 primer in an Ercoupe. It shows AN816-2D fittings screwed into female 1/8" pipe threads on the primer.
Looks like yours is an "outie" and you need an "innie"....
21st Century definitions, by Joseph Sobran
Need - Wanting to get someone else's money.
Greed - Wanting to keep your own money. (Used to mean what "need" means today)
Compassion - A politician's willingness to arrange the transfer.