Forget about those instructions.
They are not showing enough details.
The bottom plate of the accelerator pump is critical.
If the check ball in the bottom of that plate is corroded with rust and pitting or the sealing surface you must replace that bottom plate and check ball.
There are two of these one way check valves and one is in the top edge of the float bowl.
That one keeps fuel from draining back down into the bottom of the accelerator pump.
Take a small plastic straw and test it. air should only go one direction.
The prass plug or plastic plug can be carefully removed pried out with a miniture screw driver and the spring and ball will come out.
If you roll the steel ball around on a piece sand paper you can clean it.
But look at the ball with a magnifying glass to see if it is pitted.
Test it after it is all put back together.
Look into the intake and (ENGINE OFF) and gas on and see that when you turn the throttle a couple times that gas should squirt out of the brass nozzle sticking up. Check all 4.
On a Roadstar Adventure.