The spark plug gap is the distance between the center electrode and the ground electrode. The gap is critical for proper ignition of the air/fuel mixture in the combustion chamber. If the gap is too small, the spark will not be able to jump the gap and the engine will not start. If the gap is too large, the spark will be weak and the engine will run poorly.
The correct spark plug gap for an Onan generator is typically between 0.030 and 0.045 inches. The exact gap will vary depending on the model of generator. Consult your generator's owner's manual for the correct spark plug gap.
How to Gap a Spark Plug
1. Remove the spark plug wire.
2. Use a feeler gauge to measure the gap between the center electrode and the ground electrode.
3. If the gap is too small, carefully bend the ground electrode away from the center electrode until the gap is correct.
4. If the gap is too large, carefully bend the ground electrode toward the center electrode until the gap is correct.
5. Reinstall the spark plug and reconnect the spark plug wire.
Spark Plug Gap Maintenance
The spark plug gap should be checked and adjusted if necessary at regular intervals. Consult your generator's owner's manual for the recommended maintenance schedule.
