10.25
ELECTRICAL
10
DC / CDI IGNITION SYSTEM (NON-EFI MODELS)
DC / CDI Ignition System Overview
This engine uses a DC / CDI ignition system.
Some of the advantages of DC ignition are:
• Stronger, more consistent spark at low rpm for better
performance
•Easier starts
• Simpler component design for ease of trouble shooting
and maintenance
Operation Overview:
The DC / CDI system relies on battery power for ignition.
Instead of generating DC voltage via magnetic induction, a 12
volt DC current is supplied directly to the CDI unit from the
battery.
At the CDI, 12 volt DC current charges an internal capacitor to
build up the initial ignition charge. A small A/C signal from the
Trigger (Pulse) coil closes a thyristor (located in the CDI) at a
point pre-determined in the crankshaft rotation by magnets on
the flywheel’s outer diameter. This signal releases the electrical
charge which saturates the coil for ignition. DC/CDI systems
have the ability to ignite with as little as 6 volts of power.
NOTICE: Do not remove the wiring harness from the CDI box
while the key switch is on or while the engine is running.
Damage to the CDI box may occur!
Ignition System Troubleshooting
No Spark, Weak or Intermittent Spark
•Spark plug gap incorrect
• Fouled spark plug
• Faulty spark plug cap or poor connection to high
tension lead
•Related wiring loose, disconnected, shorted, or
corroded
• Engine Stop switch or ignition switch faulty
• ETC switch misadjusted or faulty
•Wire harness or connections wet, corroded.
• Poor ignition coil ground (e.g. coil mount loose or
corroded)
•Faulty stator (measure resistance of all ignition related
windings)
•Incorrect wiring (inspect color coding in connectors
etc)
•Faulty ignition coil winding (measure resistance of
primary and secondary)
• Worn magneto (RH) end Crankshaft bearings
•Sheared flywheel key
•Flywheel loose or damaged
•Trigger coil air gap too wide (where applicable) -
should be .016 - .030" (.4 - .75 mm)
• Excessive crankshaft runout on magneto (RH) end -
should not exceed .0024”
• Faulty CDI module
Maximum Timing
NOTE:
DC/CDI systems and
components are not
interchangeable with
any other system.
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