Honda SH300 2006 Manual page 506

POOR PERFORMANCE AT LOW AND IDLE SPEED
1. Inlet Pipe Leaking Inspection
Check for leaks at the inlet pipe.
Does it leak?
YES
NO
2. Spark Plug Inspection
Remove and inspect the spark plug.
Is spark plug in good condition?
YES
NO
3. Spark Test
Perform spark test.
Is there weak or intermittent spark?
YES
NO
4. Ignition Timing Inspection
Check the ignition timing.
Is the ignition timing correct?
YES
NO
5. Valve clearance Inspection
Check the valve clearance.
Is the valve clearance correct?
YES
NO
6. Cylinder Compression Inspection
Test the cylinder compression.
Is the compression within specification?
YES
NO
– • Loose inlet pipe mounting nut
• Damaged inlet pipe O-ring
– GO TO STEP 2.
– GO TO STEP 3.
– • Plug not serviced frequently enough
• Incorrect spark plug heat range
• Incorrect spark plug gap
• Dirty air cleaner element
– GO TO STEP 4.
– • Faulty spark plug
• Fouled spark plug
• Opened or shorted spark plug wire
• Faulty ignition coil
• Faulty CKP sensor
• Faulty ECM
– GO TO STEP 5.
– • Faulty CKP sensor
• Faulty ECM
– GO TO STEP 6.
– Improper valve clearance
– GO TO STEP 7.
– • Valve stuck open
• Worn cylinder and piston rings
• Damaged cylinder head gasket
• Seized valve
• Incorrect valve seat contact
TROUBLESHOOTING
25-5