Jimmy, while piston move from TDC to BDC,  fuel transferred via this hole, the fuel pressure make the floater up, and pressure on spring, and then <font color="#0066cc">rocker</font> <font color="#0066cc">arm</font> down. when piston move from BDC to TDC, floater down and close, and <font color="#0066cc">rocker</font> <font color="#0066cc">arm</font> up. floater control the fuel transition rate.

So please push <font color="#0066cc">rocker</font> <font color="#0066cc">arm</font>, and see if spring can backspring when your finger leave from <font color="#0066cc">rocker</font> <font color="#0066cc">arm</font>, same level is not neccessary.