Honda SH125 Manual page 353

TROUBLESHOOTING
ENGINE DOES NOT START OR IS HARD TO START
1. Spark Plug Inspection
Remove and inspect spark plug.
Is there spark plug in good condition?
NO
-
Incorrect spark plug heat range
Incorrect spark plug gap
Dirty air cleaner element
YES
-
GO TO
STEP
2.
2. SparkTest
Perform spark test.
Is the spark good?
NO
-
Faultysparkplug
Fouled spark plug
Faulty ignition system (page 18-4)
YES
-
GO TO STEP 3.
3. Fuel Injection System Inspection
Check the fuel injection system (page 5-7).
Is the fuel injection system normal?
NO
-
Faulty fuel injection system.
YES
-
GO TO STEP 4.
4. Fuel Line Inspection
Check the fuel line (page 5-31).
Is the fuel line normal?
NO
-
Faulty fuel line or fuel pump system.
YES
-
GO TO STEP 5.
5. Cylinder Compression Inspection
Test cylinder compression.
Is the compression within specification?
NO
-
Valvestuckopen
W o r n cylinder and piston rings
Seized valve
Incorrect valve seat contact
improper valve timing
YES
-
GO TO STEP
6.
6. Engine Starting Condition
Start the engine by following the normal procedure.
Does the engine start but then stops?
YES
-
lntakeair leak
Faulty idle air control (IAC) valve in engine control module (ECM)
Improper ignition timing (faulty ECM or CKP sensor)
Contaminated fuel
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