What are all these o rings and gaskets for?

[sprucegagt]

I have the same problem. Bought a re-built engine that came with the gaskets they didn't use. I'm wondering what #14 is. A hard plastic washer.

Oil drain plug

[tataylor]

Thanks. Wish I thought of that before I filled the crankcase with oil. Guess I'll just change it at the first oil change.