Ddis Ignition Timing - MerCruiser GM4 Service Manual

4. Reinstall cover. Tighten screws securely.
5. Connect wires.
a - Connect Wires

DDIS Ignition Timing

1. Connect timing light to No.1 spark plug. Connect
power supply leads on light to battery.
! CAUTION
If the following procedure is performed out of wa-
ter, a water source must be supplied to the water
intake openings in gear housing.
2. Start engine and run at normal idle speed (under
900 RPM - use tachometer in boat instrumenta-
tion).
Index
4B - 20 - IGNITION SYSTEM
a
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3. Adjust timing by loosening clamp and rotating
motion sensor, as required, until timing mark on
pulley aligns with 8 BTDC mark on tab. Torque
clamp bolt to 20 lb. ft. (27 N·m) , and recheck loca-
tion of timing mark.
4. Stop engine and disconnect timing light.
IMPORTANT: GM engine timing marks (on tab) are
in 2 increments. Timing must be set on the "BE-
FORE" (Advance) side of "0" (Top Dead Center).
a
Timing Marks on GM 4-Cylinder Engines
a - Timing Mark
b - Degree Marks
b
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