Mariner 100, Service Manual, Page: 20 / 391

90-13645--2 1095 2A-1 ELECTRICAL AND IGNITION
Description
The outboard ignition system is alternator-driven with
distributor-less capacitor discharge. Major compo-
nents of the ignition system are the flywheel, stator,
trigger, switch box, ignition coils and spark plugs.
The stator assembly is mounted stationary below the
flywheel and has 2 capacitor charging coils. The
flywheel is fitted with permanent magnets inside the
outer rim. As the flywheel rotates the permanent
magnets pass the capacitor charging coils. This
causes the capacitor charging coils to produce AC
voltage. The AC voltage then is conducted to the
switch box where it is rectified and stored in a
capacitor.
The trigger assembly (also mounted under the
flywheel) has 3 coils. The flywheel has a second set
of permanent magnets (located around the center
hub). As the flywheel rotates the second set of
magnets pass the trigger coils. This causes the
trigger coils to produce an AC voltage that is
conducted to an electric Silicon Controlled Rectifier
(SCR) in the switch box.
The switch discharges the capacitor voltage into the
ignition coil at the correct time and firing order
sequence.
Capacitor voltage is conducted to the primary side of
the ignition coil. The ignition coil multiplies this voltage
high enough to jump the gap at the spark plug.
The preceding sequence occurs once-per-engine-
revolution for each cylinder.
Spark timing is changed (advanced/retarded) by
rotating the trigger assembly which changes each
trigger coil position in relation to the permanent
magnets on the flywheel center hub.
IMPORTANT: If the engine misfires, runs rough or
does not start, the ignition system should be
checked using a Multi-Meter/DVA Tester
(91-99750), or a voltmeter (capable of measuring
400 volts DC, or higher) and Direct Voltage Adap-
tor (91-89045).
Test Procedures
Direct Voltage Adapter (DVA) Tests
WARNING
DANGER - HIGH VOLTAGE/SHOCK HAZARD! Do
not touch ignition components and/or metal test
probes while engine is running and/or being
“cranked.” STAY CLEAR OF SPARK PLUG
LEADS. To assure personal safety, each
individual spark plug lead should be grounded to
engine.
To protect against meter and/or component
damage, observe the following precautions:
400 VDC* test position (or higher) MUST BE
used for all tests.
INSURE the Positive (+) lead/terminal of DVA is
connected to the Positive (+) receptacle of
meter.
DO NOT CHANGE meter selector switch
position while engine is running and/or being
“cranked.”
Switch box MUST BE GROUNDED during tests.
Running or “cranking” engine with switch box
ungrounded may damage switch box.
CAUTION
* If using a meter with a built-in DVA, the DVA/400 VDC test posi-
tion should be used.
NOTE: Test leads are not supplied with the DVA. Use
test leads supplied with meter.
Test procedures and specifications are provided for
checking primary ignition voltage while the engine
is running and/or being “cranked.”
TROUBLESHOOTING TIPS:
1. Intermittent, weak, or no spark output at two
spark plugs usually indicates a bad TRIGGER.
2. Intermittent, weak, or no spark output at all three
spark plugs usually indicates a bad STATOR or
SWITCH BOX.
3. Intermittent, weak, or no spark at any one spark
plug usually indicates a bad SPARK PLUG,
COIL, or SWITCH BOX.