Spark Plug Wires - Mercury MerCruiser MCM 454 Mag MPI Service Manual

IGNITION SYSTEM

Spark Plug Wires

CHECKING
1. Visually inspect spark plug wires for damage, such as being cracked, cut or oil soaked.
2. Visually inspect spark plug boots for damage.
NOTE: Use care when removing spark plug wires and boots from spark plugs. Twist the boot
1/2 turn before removing. Firmly grasp and pull on the boot to remove the wire end.
3. Check spark plug wires for continuity using a Multi-Meter, Digital/Volt/Ohm Meter, or
similar. Replace any plug wires that do not show continuity from end to end.
4. Replace any damaged plug wires.
REPLACING
IMPORTANT: Wire routing must be kept intact during service and followed exactly
when wires have been disconnected or when wire replacement is necessary. Failure
to route wires properly can lead to radio frequency interference, cross firing of the
plugs, and/or shorting of leads to ground.
IMPORTANT: Use only spark plug wires recommended for Marine application.
NOTE: When replacing spark plug wires, it is good practice to replace one wire at a time
to reduce the risk of error.
1. Disconnect individual spark plug wires.
2. Install spark plug wires in proper order. Observe the following:
IMPORTANT: When replacing plug wires, route the wires correctly through the proper
supports. Correct positioning of spark plug wires and supports is important to
prevent cross-firing.
a. Position wires in spark plug wire supports and retainers, as provided.
b. Attach plug wires to appropriate spark plug and terminal on distributor cap. Each end
Engine Rotation And Firing Order
IMPORTANT: Before installing coil wire (high tension lead) to coil, apply approxi-
mately 1/2 oz. of Silicone Dielectric Compound, an electrical insulating compound
(Quicksilver 92-802882A1), around top of coil high tension lead tower. Do not apply
to inside of tower hole.
c. Apply Silicone Dielectric Compound. Attach coil wire (high tension lead) to center
Index
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should fit securely.
4
8
a - Front
terminal on distributor cap.
6
3
8
5
6
4
7
2
1
2
SERVICE MANUAL NUMBER 23
7
5
a
3
1
90-861326--1 MARCH 1999