1996-2002 Kawasaki 1100ZXi Jet Ski Factory Service Manual., Page 191Get this manual
SUPPLEMENT 1997- 1999 MODELS 16-7 Technical Information
7) When the throttle valve [3] opens, the engine runs at mid-range or higher speedsThe pressure in the venturi [2] drops as the air flow speed through it risesThis pressure drop allows the check valve [I81to open and fuel flows through the main jet [19], the needle jet [20], past the jet needle [21], and into the ventur[2] on its way into the engine The low pressure in the venturi [2] also acts on the diaphragm [4-21, which pulls the slide [4] increasing the area of the venturiThe diaphragm 14-21 moves the slide until the pressure of the vacuum slide spring [5] is high enough to overcome the force of the diaphragmAs the slide moves, it pulls the jet needlle [21] out of the needle jet [20], increasing the clearance between the two and allowing more fuel to join the air going to the engineThe parts on the carburetor are designed to balance the air to fuel ratio for the best fuel economy, power, driveability, and lowest exhaust emissions-