Notice: Operating an engine without an effective crankcase ventilation system may damage the engine. Replace the Positive Crankcase Ventilation (PCV) valve at regular intervals. Use the correct PCV valve for the engine and equipment type. Wrong or substandard parts may damage the engine components.

Use the following procedure to check the function of the crankcase ventilation system:

1. Start the engine.
2. Run the engine at idle.



3. Place your thumb over the end of the crankcase ventilation valve to check for vacuum. Check for a plugged intake manifold port, crankcase ventilation valve or vacuum hoses, if there is no vacuum at the crankcase ventilation valve. Replace or repair as necessary.



4. Remove the crankcase ventilation valve (4).



5. Shake the crankcase ventilation valve while listening for the rattle of the needle inside. Replace the crankcase ventilation valve if the valve does not rattle.

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Proper operation of the crankcase ventilation system is dependent upon a sealed engine. Check that the crankcase ventilation system is functioning properly, if the build up of oil sludge or oil dilution is found. Check the engine for possible causes and correct, in order to ensure that the system will function as intended.

•	Periodically inspect the hoses and clamps in the crankcase ventilation system. Replace any components showing signs of damage or deterioration. Check for a clogged crankcase ventilation valve or a plugged hose if the engine is idling rough.