Mercury MerCruiser 5.7 Horizon, User Manual

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Section 5 - Maintenance
Page 72 90-899883173 DECEMBER 2007
11. Install the engine cover.
Positive Crankcase Ventilation Valve (PCV)
CHANGING
IMPORTANT: Use only Mercury MerCruiser replacement parts to ensure compliance with
emission regulations.
1. Remove the PCV valve from the port valve cover.
33143
a - PCV valve (hose not shown)
2. Disconnect the PCV valve from the hose and discard the valve.
3. Install a new PCV valve in the valve cover and reconnect the hose.
4. Ensure that the PCV valve is tightly seated in the valve cover.
Cleaning The IAC Muffler
!
WARNING
Fuel is flammable and explosive. Ensure the key switch is off and the lanyard is positioned
so that the engine cannot start. Do not smoke or allow sources of spark or open flame in
the area while servicing. Keep the work area well ventilated and avoid prolonged
exposure to vapors. Always check for leaks before attempting to start the engine and
wipe up any spilled fuel immediately.
NOTE: The IAC muffler may be installed in the throttle body or in the IAC adapter. Locate
your IAC muffler by removing the engine cover.
1. Remove the engine cover.