Glossary of Terms
ADI – Alternator Driven Ignition, consists of a flywheel, stator, trigger and ignition module.
ADTC - After Top Dead Center Reference on ignition timing.
BTDC - Before Top Dead Center Reference on ignition timing.
CD Ignition – Capacitive Discharge Ignition. The capacitor stores the power developed by a stator or inverter and uses a SCR to deliver the power to the ignition coil.
CDM – Capacitive Discharge Module. The CDM is a combination of the switch box and ignition coil.
Crank - Refers to the engine being turned over with the starter, not running. Spark plug wires are usually connected to a spark gap tester.
DVA – Direct Voltage Adapter. Also known as Peak voltage. The term refers to the peak voltage as read by a specialized meter or a multimeter using a adapter to convert the peak voltage in the ignition system to a DC value. Regular meters cannot read the voltages due to the frequency and duration of the pulses in the system.
Power Pack – Term used by Johnson/Evinrude for the ignition module.
RPM – Revolutions per minute. The number of times the engine rotates in one minute.
S.L.O.W. – Speed Limiting Oil Warning system. Limits the RPM of the engine to approximately 2500 RPM in order to reduce the damage to the engine caused by a no oil or overheat condition.
Spark Tester - Device used to check for spark from the ignition coil to the spark plug. Testers are normally available in 1, 4, 6 and 8 cylinder configurations.
Switch Box – Term used for Force, Mariner and Mercury ignition modules.
W.O.T. – Wide Open Throttle.