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 | 1. Start and warm up the engine. |  
 |  | 2. Remove the valve from a cover of the klapanny mechanism. Close the valve a finger. If depression is absent, check, whether the hose, an opening in an inlet collector or the valve is littered. |  
 | 3. Muffle the engine. Shake the valve. You should hear knock of a plunzher in the valve. If is not present, replace the valve. |  |