Changing; Cleaning The Flame Arrestor; Positive Crankcase Ventilation Valve (Pcv) - Mercury MerCruiser Tow Sport 5.7 LHS Manual

2. Remove the dipstick, wipe clean and reinsert.
3. Remove the dipstick, observe the fluid level and mark the cold fluid level.
4. Reinstall the dipstick, tighten the T‑handle securely. Do not overtighten.

Changing

Contact your authorized Mercury MerCruiser dealer.

Cleaning The Flame Arrestor

Fuel is flammable and explosive. Ensure that 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.
1. Disconnect and remove the crankcase ventilation hose from the fitting on the flame arrestor and valve cover.
2. Remove the flame arrestor.
e
d
c
3. Clean the flame arrestor with warm water and a mild detergent.
4. Inspect the flame arrestor for holes, cracks or deterioration. Replace if necessary.
5. Allow the flame arrestor to air dry completely before use.
6. Clean the crankcase ventilation hose with warm water and a mild detergent. Dry with compressed air or allow to air dry
completely.
7. Inspect the crankcase ventilation hose for cracks or deterioration. Replace if necessary.
8. Install the flame arrestor, sealing washer, and locknut. Tighten securely.
9. Connect the crankcase ventilation hose to the fitting on the flame arrestor and valve cover.

Positive Crankcase Ventilation Valve (PCV)

Changing
IMPORTANT: Use only Mercury MerCruiser replacement parts to ensure compliance with emission regulations.
NOTE: On V6 models the PCV valve is non‑serviceable and is an internal component of the valve cover.
90-8M0086943 DECEMBER 2014
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a
a - Locknut
b
b - Sealing washer
c - Typical carburetor
d - Crankcase ventilation hose
e - Flame arrestor
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WARNING
Section 5 - Maintenance
Page 47