Just look up the parts list between the 2 mowers. Odds are they are the same as I recall honda had many variations of this type of mower.
https://www.hondalawnparts.com/honda-hr21-hr214-hr215-hr216-lawn-mower-parts
If money is your issue, you could just make yourself one. I mean a paint can, drill 2 holes - 1 for extraction hose, 1 for vacuum to suck the oil out into the paint can. You can get fancy and get 2 rubber grommets for the holes.
When it DID run, does the pull cord feel the same or do u find it alot easier to pull now?
With the low compression, and if it was harder to pull when it ran, maybe some dirt is holding the valve open a hair lowering the compression?!?!?
Take off the cyl head and see if the valves are totally...
Well, Stihl had Zenoah originally made their trimmers\blowers\etc to test the waters before making more than just chainsaws.
I am not endorsing Stihl, just saying.