TROUBLESHOOTING
ENGINE DOES NOT START OR IS HARD TO START
1. Fuel Line Inspection
Check fuel flow to carburetor.
Does fuel reach the carburetor?
IMO - • Clogged fuel hose or fuel strainer
• Clogged fuel valve
• Clogged fuel tank breather hose
YES - GO TO STEP 2.
2. Spark Plug Inspection Remove and inspect spark plug.
Is the spark plug wet?
YES - • Flooded carburetor
• Throttle valve open
• Dirty air cleaner
• Improperly adjusted pilot screw
NO - GO TO STEP 3.
3. Spark Test Perform spark test.
Is there weak or no spark?
YES - • Faulty spark plug
• Fouled spark plug
• Loose or disconnected ignition system wires
• Broken or shorted ignition coil wire
• Faulty ignition coil
• Faulty igniting pulse generator
• Faulty exciter coil
• Faulty engine stop button
• Faulty ignition control module (ICM)
NO - GO TO STEP 4.
4. Engine Starting Condition
Start engine by normal procedure.
Does the engine start then stops?
YES - • Improper choke operation
• Incorrectly adjusted carburetor
• Leaking carburetor insulator
• Improper ignition timing (Faulty ICM or ignition pulse generator)
• Contaminated fuel
• Improper hot start operation
NO - GO TO STEP 5.
5. Cylinder Compression Inspection
Test cylinder compression.
Is the compression low?
YES - • Valve clearance too small
• Valve stuck open
• Worn cylinder and piston rings
• Damaged cylinder head gasket
• Seized valve
• Improper valve timing
• '05 - '07: Faulty decompressor cam
• After '07: Faulty decompressor shaft
[1] If the engine runs rich exiting a corner, turn the pilot screw clockwise to lean the mixture.
• If the engine runs lean exiting a corner, turn the pilot screw counterclockwise to richen the mixture.
