The system consists of a flame arrester valve and a pneumatic shock absorber mounted on the carburetor (on models with manual transmission), throttle control.
A symptom of a malfunctioning pneumatic valve is the immediate closing of the throttle when the accelerator pedal is suddenly released. Flame arrester failure can manifest itself in the form of reverse flames of the burning mixture and in the continued operation of the engine after the ignition has been turned off.
Checking the technical condition
Flash hider
Pic. 8.5. Checking the flame arrester valve
Start the engine and put your hand on top of the flame arrester (pic. 8.5).
Attention! Increase engine speed to 3000 min-1
, then quickly release the throttle. The flame arrester is working properly if you can feel the flow of air from it.
Set the engine to idle. Disconnect the air hose from the flame arrester and plug the hose inlet. If the engine idle speed after disconnecting the air hose is very different from the speed before disconnection, then there is a leak - the flame arrester should be replaced.
Pneumatic shock absorber
Pull the throttle lever sharply away from the air spring and check the speed of the air spring over its entire length. Release the throttle lever and check that after contact with the air damper rod, the lever returns smoothly to the idle position.
To adjust the air spring, start the engine, warm it up and let it idle.
Connect a tachometer. While slowly increasing the engine speed, check if the air damper rod moves away from the throttle lever at about 2200 min-1. To adjust, loosen the locknut and tighten the air damper.
If the air spring does not operate as intended after adjustment, replace it.
Replacement Parts
Flash hider
Remove the air supply hose and, having pressed the latches, disconnect the flame arrester from the bracket.
Install a new flame arrester in the bracket and connect the air supply hose.
Pneumatic shock absorber
Pic. 8.6. Pneumatic shock absorber with mounting and drive elements
Loosen the locknut and remove the air spring from the bracket (pic. 8.6).
Install a new air spring and adjust as described above.