PA 8N........you do know that the 8N uses a gravity fed system and sometimes the domed gastank vent gitts CLOGGED by mud-daubers and prevents the fuel tank from draining due to VACUUM in the fuel tank. Crack yer gascap to relive the vacuum. Simple, eh?
Also replace yer 8N's gascap with new and improved NAA gascap, 'cuz it is self-venting. Simple, eh?
You do know oil thins with TEMPERATURE, don't you??? And THIN oil does NOT generate much oil pressure, just as you are experiencing and complaining about. While the N-Engine was designed for 30wt detergent oil, the Owners manual also suggested changing to 40wt oil in HOT climates. Modern 10-30wt oil is really THIN 10wt oil with temperature sensitive additives that make it act like 30wt. Ain't NO LAW that sez you can't even use 50wt RACING oil in HOT temperatures. 6-qts and change yer filter. Simple, eh? ........oily Dell