Mercury E5ZZ-6A666-A Valve Assembly

Hydrocarbon emissions are reduced by the Positive Crankcase Ventilation (PCV) system which scavenges crankcase vapors, passes them through the air cleaner, and mixes them with blow-by gases before redirecting them back to the intake manifold through a PCV valve. The main components of the PCV system are, fresh air filtered inlet, vacuum hoses connecting these two components with the engine and EECS system, and PCV valve. The flow is restricted when there is high intake manifold vacuum so as to maintain idle quality, this is achieved by using PCV valve. When abnormal operating conditions occur, the system allows excessive amounts of blow-by gases to pass back into the air cleaner through the crankcase vent tube for normal combustion.