While looking around for spare parts for my engine, I came across this website that has Parts Catalogs for Yanmar engines.
What's nice is that there are diagrams for the engines with an exploded view and a list of parts that go to certain places. You can be sure to find the correct part knowing where it goes too. Just note that some part numbers may have been updated. Also be sure that the engine type is correct. While I have a Yanmar 2GM, the parts for a 2GM20 could be slightly different. There are separate files for each.
Torrenson Marine seems to have a large number of parts online and if doing a search for a part, their website may inform you of an updated part. So if you're like me, do the research and be sure you get the right part.
I hope this can be a useful resource for others.