Intake Manifold; Removal; Cleaning And Inspection - Mercury MerCruiser MCM 454 Mag MPI Service Manual

SERVICE MANUAL NUMBER 23

Intake Manifold

Removal

1. Drain engine cooling system.
2. Disconnect hoses from thermostat housing.
3. Disconnect intake manifold-to-circulating pump by-pass hose from circulating pump.
4. Disconnect electrical leads interfering with removal.
5. Disconnect crankcase ventilation hoses from rocker arm covers.
6. Disconnect throttle cable. Remove fuel line from fuel rail.
7. Remove distributor cap and mark position of rotor on distributor housing. Also, mark
IMPORTANT: Do not crank engine over after distributor has been removed.
8. Remove other ignition components.
9. Disconnect any other miscellaneous items that will prevent removal of manifold.
IMPORTANT: It may be necessary to pry intake manifold away from cylinder heads
and block in next step. Use extreme care to prevent damage to sealing surfaces.
10. Remove intake manifold bolts, then remove intake manifold and carburetor assembly.
NOTE: If intake manifold requires replacement, transfer all remaining parts to new manifold.

Cleaning and Inspection

1. Clean gasket material from all mating surfaces.
IMPORTANT: When cleaning cylinder head mating surface, do not allow gasket mate-
rial to enter engine crankcase or intake ports.
2. Inspect manifold for cracks or scratches. Machined surfaces must be clean and free of
3. Check intake passages for varnish buildup and other foreign material. Clean as neces-
Index
90-861326--1 MARCH 1999
Downloaded from https://needmanual.com/
For repair procedures on "Fuel Injection Engines," refer to Section 5C.
position of distributor housing on intake manifold. Remove distributor.
all marks and deep scratches or leaks may result.
sary.
NOTICE
454 CID (7.4L) / 502 CID (8.2L)
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