General Information; Engine Identification - Mercury MerCruiser MCM 454 Mag MPI Service Manual

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454 CID (7.4L) / 502 CID (8.2L)

General Information

Some of the repairs in this section must be completed with engine removed from boat.

Engine removal depends upon type of repair and boat design. Place engine on repair stand

for major repairs.

When engine removal is not required, make certain that battery cables are disconnected

at the battery prior to performing any on-board repair procedures.

Lubricate all moving parts (during reassembly) with engine oil. Apply Quicksilver Perfect

Seal on threads of and under heads of cylinder head bolts, and on threads of all cylinder

block external bolts, screws and studs.

The MerCruiser Model can be determined by looking at the last two letters of the engine

code stamped into the cylinder block. This code number is stamped on all MerCruiser power

packages and replacement partial engines, but not replacement cylinder block assemblies.

If the engine serial number and/or model decals are missing, the engine code letters may

help in determining the engine models. Following is a list of GM engines and their respective

code letters.

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Location Of GM Engine Code

MCM (Sterndrive)

MIE (Inboard)

SERVICE MANUAL NUMBER 23

90-861326--1 MARCH 1999

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