Prying with an awl, remove the retaining ring of the throttle actuator of the second chamber.
Using a Phillips screwdriver, unscrew the two screws securing the pneumatic drive housing,...
... remove it and the gasket.
We check the serviceability of the diaphragm of the pneumatic actuator or replace it by analogy with the starting device.
Pressing on the diaphragm rod, close the inlet with your finger.
In a serviceable pneumatic drive, the stem will fully return to its original position only after opening the inlet.
We do not recommend disassembling the body of the pneumatic drive without the need, as you will have to select the length of the rod experimentally.
If the diaphragm mechanism of the pneumatic actuator of the second damper was disassembled, we adjust the length of its thrust:
Loosen the lock nut...
... and adjust its length so that when the throttle of the second chamber is fully closed, the thrust hole is opposite the intermediate lever finger.
We put the rod on the finger and fix it with a retaining ring.
By pressing on the rod, we sink it into the body of the diaphragm mechanism. (When the damper of the first chamber is closed, the second should remain closed).
Holding the diaphragm rod pressed, we open the shutter of the first chamber with the lever, while the shutter of the second chamber should automatically open. If the damper is not fully opened, shorten the rod. At the end of the adjustment, tighten the lock nut of the thrust.
A malfunction of the pneumatic drive is often caused by a violation of the tightness of the channels through which the vacuum is supplied to the diaphragm. In this case, it is necessary to check the bottom plane of the carburetor body (see Disassembly and repair of the carburetor body). As a result of overtightening the carburetor mounting nuts, it can be bent - the required vacuum is not created and the shutter of the second chamber does not open or does not open completely, with a delay.