Honda CRF50F 2004-2015 Service Manual page 203

TROUBLESHOOTING
ENGINE DOES NOT START OR IS HARD TO START
16-2
1. Carburetor Inspection
Check the fue l flow to carburetor.
Is fuel reaching the carburetor?
NO _ . Clogged fuel tine and strainer
• Clogged fuel tank breather hose
YES - GO TO STEP 2.
2. Spark Tes t
Perform a spark test.
Is there
a
good spark?
NO _ . Faulty spark plug
• Fouled spark plug
• Faulty ignition control module
• Broken or shorted spark plug wire
• Faulty igniting pulse generator
• Faulty engine stop switch or ignition switch
• Loose or disconnected ignition system wires
YES - GO TO STEP 3.
3. Sparic Plug Inspection
Remove and inspect spark plug.
Is the spark plug in good condition ?
NO • Flooded carburetor
• Choke val ve closed
• Air cleaner dirty
YES - GO TO STEP 4.
4. Engine Start Condition
Start by following the normal procedu re.
Does the engine start but then stop?
YES - . Improper choke operation
• Ca rburetor incorrectly adjusted
• Intake pipe leaking
• improper ignition timing (faulty ignition coil or ignition pulse generat or)
• Fuel contaminated
NO - GO TO STEP 5.
5. Cylinder Compression Inspection
Test
cylinder compression .
Is the compression normal?
NO _ . Valve clearance too small
• Valve stuck open
• Worn cylinder and piston ring
• Damaged cylinder head gasket
• Seized valve
• Improper valve timing