the middle adjustment is the throttle ie screw in for more power.
the adjuster nearest the waste valve is screwed in just enough so the valve opens & shuts automatically
these two adjustments are the main ones.
The third adjustment tends to be a one off adjustment.
For a powerful site ie large drop in river (less than 2-3m) is screwed in some what & visa versa
Ralph Glockemann
March 2014