Thanks for the quick advice. Losing light here, so I went right out to work down your list.

1. Piston rings - I do not know how to check
2. Tiny drain hole - where? Do not see one.
3. Mesh is not dry, but to saturated either
4. Breather hose - the end to the carb comes off easily, other end resisted. can it be pulled off?
5. disc is thicker than I expected, not worn through.

Some pictures:
The breather compartment, a bit wet so I will dry it out. Gasket is old, but was not "blown out".
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The disc is hard, black plastic:
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The black rubber seal seemed a bit loose, it was not very hard to take out.
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Looking down the shaft, I can see what looks like bearings - probably not good?
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