Mercury MerCruiser MCM 454 Mag MPI Service Manual page 585

FUEL INJECTION SYSTEM TROUBLESHOOTING
Rough, Unstable, or Incorrect Idle, Stalling Symptom (Continued)
17
18
19
20
Index
Page 5D-26
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1. Check the following
Mechanical items:
Check compression.
Sticking or leaking valves.
Worn camshaft lobe(s).
Valve timing.
Broken valve springs.
2. If a problem is found, repair as nec-
essary.
Was a problem found?
1. Check intake valves for valve
deposits.
2. If deposits are found, remove as
necessary.
Were deposits found on the intake
valves?
1. Check for faulty motor mounts.
2. If a problem is found, repair as nec-
essary.
Was a problem found?
1. Review all diagnostic procedures
within this table.
2. If all procedures have been com-
pleted and no malfunctions have
been found, review/inspect the fol-
lowing:
Visual/physical inspection.
Scan tool data.
All electrical connections within a
suspected circuit and/or system.
3. If a problem is found, repair as nec-
essary.
Was a problem found?
Engine
Go to OBD
System
-
Check
Go to OBD
System
-
Check
Go to OBD
System
-
Check
Go to OBD
System
-
Check
SERVICE MANUAL NUMBER 23
Go to Step 18
Go to Step 19
Go to Step 20
Contact
MerCruiser
Customer
Service
90-861326--1 MARCH 1999