Help identifying Honda BF50 Part

[Fullmetaljake]

Looking for help identifying this part. Looks to be a threaded plug in the top of the block but is not listed on any parts lists that I can find. I’ve isolated a small oil leak from the top of the plug and I’m trying to learn what its purpose is. Thanks,
Jake

 

[Tegweni]

When the motor was cast in the factory oil and water passages are filled with sand when they finished the sand is drained through these holes earlier motors were then fitted with welsh plugs now days Honda calls them bolt sealing plugs

 

[Fullmetaljake]

Thank you. Any idea if i can find a replacement plug anywhere? Is there a gasket underneath the plug that could be damaged causing the leak or am i looking at damaged threads or possibly a crack in the block around the plug?

 

[iang6766]

Remove the plug and inspect it, it should have a. aluminum washer, just coat the thread with a good sealant a d reinstall