Suzuki DF 40 - Page 67

ENGINE CONTROL SYSTEM 3-12
CONTROL MODE
WHEN CRANKING :
The ignition timing is fixed at BTDC 7° until the engine starts.
WHEN IDLING / TROLLING :
The ignition timing is controlled to within the range of BTDC 5° to 13° to provide stable engine operation at
the specified idling / trolling speed.
When the shift lever is in neutral, if engine speed exceeds 1200 r / min , ignition timing remains fixed at
BTDC 9°.
WHEN RUNNING (NORMAL OPERATION) :
The ignition timing ranges between BTDC 0° – 32° (DF40) or 25° (DF50), 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.
IGNITION TIMING CHART
The following chart is an example for ignition at BTDC30°.
SPECIFICATION
Ignition system Full-transistorized ignition
Advance Electronic microcomputer control
Ignition timing DF 40 : BTDC 0° – 32°, DF 50 : BTDC 0° – 25°
Firing order 1 – 3 – 2
CKP Sensor Signal 1
CKP Sensor Signal 2
CKP Sensor Signal 3
CMP Sensor Signal
#1 Ignition Signal
#3 Ignition Signal
#2 Ignition Signal
In.: Intake, Cm.: Compression, Ep.: Explosion Ex.: Exhaust
BTDC 65° on #1 exhaust stroke
120° 120° 120°
60°
30°
30°
ON
OFF
Spark timing
TDC
TDC
TDC
TDC
TDC
TDC
TDC
TDC
TDC TDC
TDC
TDC
TDC
TDC
TDC
TDC
TDC
In. Cm. Ep. Ex. In. Cm. Ep. Ex. In. Cm. Ep. Ex.
Cm.In.Ex. In. Cm. Ep. Ex. In. Cm. Ep. Ex. E
Cm. Ep. Ex. In. Cm. Ep. Ex. In. Cm. Ep. Ex. In.