4-26
Outboard motor troubleshooting
Symptom 1: Unstable engine idle speed, poor acceleration, poor performance, or limited en-
gine speed.
Symptom 2 Cause Checking steps
See
page
Spark plug does not
produce a spark
(some cylinders)
Spark plug malfunction Check the spark plug. 7-30
Short, open, or loose con-
nection in ignition coil circuit
Measure the ignition coil input volt-
age.
5-37
Check for wiring continuity between
the ignition coil and the engine ECM.
A-12
Check for wiring continuity between
the ignition coil and the main relay.
A-12
Ignition coil malfunction
Exchange the ignition coil with a dif-
ferent one, and then check the igni-
tion spark.
5-37
Engine ECM malfunction Replace the engine ECM. 7-28
Fuel pressure is low
Fuel leakage Check for fuel leakage. 2-46
Clogged fuel filter
Check the fuel filter for dirt and ob-
structions.
6-7
High-pressure fuel pump
malfunction
Measure the high-pressure fuel
pump resistance.
5-32
Fuel not supplied
(some cylinders)
Fuel injector malfunction
Check the fuel injector operation us-
ing the YDIS.
5-31
Measure the fuel injector resistance. 5-31
Short, open, or loose con-
nection in fuel injector cir-
cuit
Measure the fuel injector input volt-
age.
5-31
Check for wiring continuity between
the fuel injector and the main relay.
A-11
Check for wiring continuity between
the fuel injector and the engine ECM.
A-11
Clogged fuel injector Replace the fuel injector. 6-28
Engine ECM malfunction Replace the engine ECM. 7-28
Compression pres-
sure is low
Improper valve timing
Check the valve timing. 7-35
Check the timing belt. 7-35
Compression leakage
Check the valve for bends and stick-
ing.
7-51
Check the piston and piston rings for
damage.
7-71
Check the cylinder for scratches. 7-73
To Next Page
