If there is a spark from the coil but not from the spark plugs, what would this indicate?

If there is a spark from the coil but not from the spark plugs, this condition suggests that while the ignition coil is functioning and producing a spark, that spark is not reaching the spark plugs effectively. This points to a potential issue within the ignition system's delivery components, particularly the rotor brush.

The rotor brush is responsible for directing the electrical current from the coil to the appropriate spark plugs in the ignition system. If the rotor brush is faulty or worn, it can fail to transmit the high-voltage spark needed to ignite the air-fuel mixture in the combustion chamber, resulting in no spark at the plugs despite the coil's operational status.

By contrast, a defective spark plug would typically show no spark from the coil itself as it would likely fail to create a spark upon receiving the signal. A faulty ignition coil would not generate any spark at all, and a disconnected battery would completely disable the ignition system, preventing any spark from being produced or transmitted. Thus, the situation described is best explained by a problem with the rotor brush not properly passing the spark to the spark plugs.