Surges And/Or Chuggles Symptom - Mercury MerCruiser MCM 454 Mag MPI Service Manual

SERVICE MANUAL NUMBER 23

Surges and/or Chuggles Symptom

Step
Definition: Engine power variation under steady throttle or cruise. Feels like the engine
speeds up and slows down with no change in the throttle lever position.
Index
90-861326--1 MARCH 1999
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Action
Was the "On-Board Diagnostic" (OBD)
1
System Check performed?
Was visual/physical check performed?
2
1. Check for engine going into rpm
reduction mode.
2. If a problem is found, repair as
3
necessary.
Was a problem found?
1. Check for contaminated fuel.
2. Check fuel
separator.
4
3. If a problem is found, repair as
necessary.
Was a problem found?
1. Check for proper fuel pressure while
the condition exists.
Refer to Table A-4 in "General Sys-
5 tem Diagnostics" section.
2. If a problem is found, repair as
necessary.
Was a problem found?
1. Check for intermittent opens or short
to grounds in the ECT sensor, MAP
sensor and TP sensor circuits. Also
check or throttle linkage sticking,
binding or worn.
6
2. An intermittent failure may not store
a DTC.
3. If a problem is found, repair as
necessary.
Was a problem found?
1. Check for proper ignition voltage
output.
Refer to Table A-7 in "General Sys-
7 tem Diagnostics" section.
2. If a problem is found, repair as
necessary.
Was a problem found?
1. Check ignition coil for cracks or
carbon tracking.
8
2. If a problem is found, repair as
necessary.
Was a problem found?
FUEL INJECTION SYSTEM TROUBLESHOOTING
Value(s)
filters and water
Yes
Go to OBD
- Go to Step 2
System Check
Go to Visual/
- Go to Step 3
Not
Applicable
to
MerCruiser
- Go to Step 4
EFI or MPI
Go to OBD
System
Go to Step 5
-
Check
Go to OBD
System
- Go to Step 6
Check
Go to OBD
System
- Go to Step 7
Check
Go to OBD
System
- Go to Step 8
Check
Go to OBD
System
Go to Step 9
-
Check
No
Physical
Check
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