TOHATSU BFT75A Service Manual page 117

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TROUBLESHOOTING
11. IAC valve inspection
Replace the IAC valve with a new one and start the engine.
Engine starts?
YES
NO
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 stop?
YES
NO
2. Engine idle speed inspection
Adjust by turning the idle adjusting screw in or out.
Start the engine.
Does the engine stall?
YES
NO
3. Spark plug inspection
Remove and inspect the spark plugs.
Is the spark plug wet?
YES
NO
4. Intake air leak inspection
Check for secondary air in the system.
Is there an air leak?
YES
NO
5. Fuel Flow Inspection
Inspect the fuel flow (page 5-99)
Is the fuel flow within specification?
YES
NO
4-4
– Faulty original IAC valve.
– Replace the ECM with a new one and recheck.
– GO TO STEP 2.
– Perform alert system/warning system troubleshooting (page 4-16).
– GO TO STEP 3.
– Adjust the idle adjusting screw (page 3-20).
– • Incorrect spark plug heat range
• Incorrect spark plug gap
• Clogged between the silencer and cylinder head
• Improper vapor separator float height
– GO TO STEP 4.
– • Loose IAC valve and/or throttle body mounting bolt
• Leaking or damaged throttle body and/or IAC valve gasket
• Loose intake manifold mounting bolt
• Leaking or damaged intake manifold seal ring
• Loose fuel line mounting bolts
• Leaking or damaged fuel injector seal ring
– GO TO STEP 5.
– GO TO STEP 6.
– • Clogged or damaged fuel tube
• Clogged fuel strainer (Low pressure side)
• Clogged water separator
• Clogged fuel strainer (Low pressure side)
• Clogged vapor separator air vent tube or filter
• Faulty vapor separator
• Clogged or damaged fuel feed hose
• Clogged fuel strainer (High pressure side)
• Faulty fuel pump (High pressure side)