Consider this o-ring :
And this full diagram if you need a more global view :
For completeness sake, here are the real parts :
The other end of the path is at the top of the venturi :
Little hole in caps where o-ring goes :
And for completeness, what goes inside :
Both-side view of the diaphragm :
What could be the result of this missing o-ring ?
My hypothesis is that a bad acceleration would occurs since air flow would be corrupted.
Am-I right and why ?