ENGINE CONTROL SYSTEM 3-13
In. Cm. Ep. Ex. In. Cm. Ep. Ex. In.
TDC TDC TDC TDC
TDC TDCTDCTDC
Spark timing
24˚
10˚
120˚ 120˚ 120˚
4-signals/720˚
34-signals/360˚
CKP sensor
signal
CMP sensor
signal
#1 ignition
signal
#3 ignition
signal
#4 ignition
signal
In. : Intake, Cm. : Compression, Ep. : Explosion, Ex. : Exhaust, TDC : Top Dead Center
ON
OFF
Ex. In. Cm. Ep. Ex. In. Cm. Ep. Ex.
TDC TDC TDC TDC
Ep. Ex. In. Cm. Ep. Ex. In. Cm. Ep.
TDC TDC TDC TDC
Cm. Ep. Ex. In. Cm. Ep. Ex. In. Cm.
#2 ignition
signal
30˚
IGNITION TIMING CHART
• The following chart shows the example for the ignition at BTDC 24°.
• The ignition timing is varied by the condition of the engine running.
• Angles indicated in the following chart show the CRANKSHAFT angle.
CONTROL MODE
WHEN CRANKING:
The ignition timing is fixed at BTDC 5° until the engine starts.
WHEN IDLING/TROLLING:
The ignition timing is controlled within the range of BTDC 4° to BTDC 16° to provide stable engine operation
at the specified idling/trolling speed.
When the shift lever is in neutral, if engine speed exceeds 1000 r/min, ignition timing remains fixed at BTDC 5°.
WHEN RUNNING (NORMAL OPERATION):
The ignition timing ranges between BTDC 10° – 33° (DF60) or 29° (DF70), depending on current engine
operating conditions.
WHEN DECELERATING:
When the throttle valve is closed suddenly, turning the CTP switch “ON”, ignition timing is delayed for a
programmed duration to prevent engine stalling or unstable running.
SPECIFICATION
Ignition system Full-transistorized ignition
Advance Electronic microcomputer control
Ignition timing DF60: BTDC 4° – BTDC 33°, DF70: BTDC 4° – BTDC 29°
Firing order 1 – 3 – 4 – 2
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