There are no diaphrams on a Q-jet....the rear secondaries have air valves above them. These open fast or slow depending on how the spring is adjusted. they expose a fuel discharge port to reduced air pressure and in turn pulls a shot of fuel to reduce lean bog from air valves opening. As air valves open with demand from secondary throttle plates, they rotate a cam that pushes a arm up proportionately lifting secondary metering rods out to let fuel into main secondary discharge nozzles.
Secondary valves are linked to primaries and open when primaries and fully opened. If you ahve a problem with full throttle power or transition from primaries to secondaries, then adjust secondary air valve tension.
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