Valve Cover Area; Cylinder Area - Mercury MerCruiser MCM 454 Mag MPI Service Manual

TROUBLESHOOTING

Valve Cover Area

Valve cover area, timed to one-half engine
speed, noise could be confined to one
cylinder or may be found in any multitude y
of cylinders

Cylinder Area

Cylinder area, may be confined to one
cylinder or found in more than one cylinder or found in more than one
cylinder, timed to engine speed
Index Index
Page 1C-16
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Location
d i ld b fi
y
Location
Rocker arm striking valve cover
Rocker arm out of adjustment
d
Worn rocker arm
y
Bent push rod
Collapsed lifter
Sticking valve
Carbon build-up
Connecting rod installed wrong
Bent connecting rod
Piston
Piston rings
Piston pin
Cylinder worn
SERVICE MANUAL NUMBER 23
Possible Causes
Possible Causes
90-861326--1 MARCH 1999