TOHATSU BFT75A Service Manual page 121

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TROUBLESHOOTING
4. IAC valve inspection
Replace the IAC valve with a new one and start the engine.
Is the idle speed normal?
YES
NO
ENGINE SPEED IS LOWER THAN THE SPECIFIED IDLE SPEED OR TROLLING SPEED AFTER
WARMING UP
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 (page 3-20).
Is the idle speed normal?
YES
NO
3. Pressure regulator inspection
Check the fuel pressure and record it (page 5-97)
Disconnect the pressure regulator vacuum tube.
Check the fuel pressure.
Is the fuel pressure higher with the vacuum tube disconnected?
YES
NO
4. IAC valve inspection
Replace the IAC valve with a new one and start the engine.
Is the engine speed stable during idle and trolling?
YES
NO
ENGINE SPEED DOES NOT INCREASE
1. Throttle link and throttle cable inspection
Inspect the throttle link and throttle cable (page 3-9).
Is the throttle link and throttle cable adjustment correct?
YES
NO
2. Propeller inspection
Match the propeller.
Is the propeller correct?
YES
NO
4-8
– 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).
– Improperly adjusted idle adjusting screw.
– GO TO STEP 3.
– GO TO STEP 4.
– • Clogged pressure regulator vacuum tube
• Faulty pressure regulator
– Faulty original IAC valve.
– Replace the ECM with a new one and recheck.
– GO TO STEP 2.
– Improper throttle link and throttle cable adjustment (page 3-9)
– GO TO STEP 3.
– Propeller mismatched.