The coasting enricher works like the slides...by vacuum. Notice in your picture the "port" path you marked in green. The coasting enricher is normally open unless higher vaccuum pushed it closed...thus blocking PAJ2. This happens to richen the mixture to prevent excessively lean mixture and exhaust popping. If you take one out, you'll see the vaccuum port which goes through the small finger-shaped piece of the enrichener diaphragm. When open, PAJ2 air mixes with PAJ1 air and onto the pilot fuel jet we go.
How accurate is the diagram?
I figure parts 15 and 16 are in the jet block so if the horizontal line is the fuel level, it appears the end of the pilot jet with the tiny hole sits above the fuel so in theory it should never get blocked as fuel level goes down when left standing for a long time.