0166-0835 | Genuine Cummins® Ignition Coil

•  Onan® CCK Series Engines: CCK, CCKA, CCKB, CCKM twin-cylinder engine models.

• Onan® Generator Sets: Commercial, RV, industrial, and standby mobile generator sets powered by Onan® CCK-series engines.

• Power & Industrial Machinery: Welders, lawn tractors, and industrial utility equipment utilizing Onan® cast-iron twin-cylinder engines.

1. What is it?

Part is an electromechanical 12V ignition coil. It functions as an induction transformer that steps up the low battery voltage (12 volts DC) into high voltage (thousands of volts) required to create an electric spark across the spark plug gaps, igniting the air-fuel mixture in the engine combustion chambers.

2. Core Functions & Technical Features

• Dual High-Voltage Outputs: Features twin high-voltage spark plug wire towers designed to feed both cylinders on Onan® oppose-twin engines simultaneously (waste-spark ignition system).

• 12V Primary Circuit: Standard 12-volt primary terminal connections designed to interface with mechanical breaker points or solid-state electronic ignition modules.

• Heavy-Duty Construction: Fully sealed and insulated against high engine vibration, heat cycling, and moisture exposure commonly found in compact generator enclosures.

1. Generator/Engine Cuts Out When Hot (Thermal Failure)

• Symptom: The engine or generator starts and runs fine cold, but abruptly dies after 10–30 minutes of operation. It refuses to restart until the coil cools down completely.

• Cause: Internal copper windings expand from engine heat, causing a temporary break (open circuit) in the primary or secondary circuit.

2. Misfiring Under Load or Engine Running on One Cylinder

• Symptom: The generator sputters, vibrates excessively, or cannot hold electrical load because one of the dual high-voltage output towers loses spark output.

• Cause: Insulation breakdown or severe corrosion inside one of the high-voltage plug wire towers.

3. No Spark / Engine Cranks But Will Not Start

• Symptom: The starter motor cranks the engine normally, but the engine fails to catch or fire at all. Testing both spark plug wires reveals no electrical arc.

• Cause: Complete open circuit or short-to-ground in the primary coil winding or burnt secondary winding.

4. Visible Physical Damage or Oil/Resin Leakage

• Symptom: The coil housing shows cracks, bulging, carbon tracking near the electrical terminals, or leaked insulation material around the body.

• Cause: Severe overheating, high internal resistance, or age-related breakdown of the internal potting compound.