Cleaning; Inspection - Mercury MerCruiser MCM 454 Mag MPI Service Manual

SERVICE MANUAL NUMBER 23
7. Remove exhaust manifold fasteners. Remove manifold assembly and discard gaskets.

Cleaning

1. Clean gasket material from all surfaces and wash parts in solvent.
2. Check water passages for foreign material. Passages must be clean for efficient cooling.

Inspection

1. If more thorough inspection is desired, pipe plugs may be removed from exhaust man-
IMPORTANT: If plugs are removed, coat threads with Quicksilver Perfect Seal before
reinstalling.
2. Check for cracks.
3. To test manifold body for leaks, block-off plates, plugs, or short hoses with plugged ends
4. Inspect all parts carefully. Machined surfaces must be clean and free of all marks and
Index
90-861326--1 MARCH 1999
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e
b
a - Exhaust Elbow
b - Restrictor Gasket
c - Open Gasket (Later Models)
d - Exhaust Manifold
e - Bolts
ifold and exhaust elbow.
must be used. One block-off plate must have a threaded hole for attaching compressed
air hose. Use new gaskets when installing block-off plate(s). Apply 40 PSI (276 kPa) of
air pressure and submerge manifold in water. Air bubbles will indicate a leak.
deep scratches, or water and exhaust leaks may result.
a
c
d
MANIFOLDS AND ELBOWS
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