The first year 40hp engine(1960) had a weak crank. Johnson offerred to replace all of the powerheads under warrantee with the next year's powerhead with a stronger crank. Some people did; some didn't.

The two little valves are crankcase puddle drains. The lower seal is carbon. It has an o-ring inside that should be replaced. If the carbon itself is not broken or scarred it can be reused.