O ring, Gascolator, Oil Strainer
Both the Yellow Gascolator Strainer on the lower port side of the Engine compartment and the Brown Oil Strainer on the lower right have a downward swinging, lid secured by a small strongback.
Is yours leaking?
These reproduction thin Viton material, square section O rings sit in the lid's groove.
Whether for fuel or oil, remember to safety wire the wing nut that secures the strongback.
Or have a look at this video, where they forgot to, on the Oil Strainer.