Spark Plugs - Mercury MerCruiser MCM 454 Mag MPI Service Manual

IGNITION SYSTEM

Spark Plugs

CHECKING
1. Disconnect spark plug wires (high tension leads) from spark plugs.
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.
2. Remove spark plugs.
NOTE: A "thin-walled" spark plug socket may be required.
3. Inspect each spark plug for manufacturer and spark plug number. All plugs must be from
the same manufacturer and have the same spark plug number. Refer to "Specifications"
section for spark plug numbers, SECTION 1B.
Index
Page 4B-4
Downloaded from https://needmanual.com/
a - Spark Plug Boot
a - Spark Plug Number
a
a
SERVICE MANUAL NUMBER 23
74073
75084
90-861326--1 MARCH 1999