Oil leak behind the cam

Thanks everyone. Luckily I saved the “extras” from the plug kit, and found this guy. I think this is what I need.
9871210F-149D-4976-8666-97B1634220D1.jpeg

I’ve been turning the crank about 1/4 revolution at a time and priming, still nothing. Is it necessary to turn the crank *while* priming? I’ll need another 12 pack to bribe a friend for that.