TOHATSU BFT250A Service Manual page 96

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TROUBLESHOOTING
ENGINE STARTS BUT STALLS SOON
1. Alert system inspection
Turn the combination switch ON.
Check the warning buzzer sound.
Does the warning buzzer sound twice and then keep sounding?
YES
NO
2. Engine idle speed inspection
Adjust by turning the idle adjusting screw in or out.
Does the engine stalls?
YES
NO
3. Spark Test
Perform spark test (page 8-4) at all plugs.
Is there weak or no spark?
YES
NO
4. Spark Plug Inspection
Remove and inspect spark plugs.
Is the spark plug wet?
YES
NO
5. Intake air leak inspection
Check for secondary air in the system.
Is there an air leak?
YES
NO
6. Fuel Flow Inspection
Inspect the fuel flow (page 5-113).
Is the fuel flow within specification?
YES
NO
4-4
– Perform alert system/warning system troubleshooting (page 4-18).
– GO TO STEP 2.
– GO TO STEP 3.
– Improper idle adjusting screw. Adjust the idle speed (page 3-23).
– Perform ignition system troubleshooting (page 8-3).
– GO TO STEP 4.
– • Incorrect spark plug gap
• Incorrect spark plug heat range
• Blockage between the cooling fan cover and cylinder head
• Improper vapor separator float height
– GO TO STEP 5.
– • Loose IAC valve and/or throttle body mounting bolt
• Leaking or damaged throttle body and/or IAC valve gasket
• Loose IAT sensor
• Leaking or damaged IAT sensor O-ring
• Loose intake manifold upper cover mounting bolt
• Leaking or damaged intake manifold upper cover seal ring
• Leaking or damaged intake manifold gasket
• Leaking or damaged injector base gasket
• Loose intake manifold and injector base mounting bolt
• Leaking or damaged fuel injector seal ring
– GO TO STEP 6.
– GO TO STEP 7.
– • Clogged fuel strainer (Low pressure side) (page 3-27)
• Clogged water separator (page 5-93)
• Clogged or damaged fuel tube
• Faulty fuel pump (Low pressure side)
• Clogged vapor separator air vent tube or filter
• Clogged fuel feed hose
• Clogged fuel strainer (High pressure side) (page 5-106)
• Faulty vapor separator (page 5-115)
• Faulty fuel pump (high pressure side)