- These spark plug service and replacement procedures apply to Yamaha EF3000iSE and EF3000iSEB inverter generators.
A spark plug is an electrical device inserted in the cylinder head of an internal-combustion engine. It delivers electrical current from the generator’s ignition system to the combustion chamber. An electric spark emits between the electrode gap—from the centre electrode to the ground electrode. The electric energy transmitted through the spark plug gap ignites the explosive air and fuel mixture so as to convert energy into power.
Spark plug maintenance
Periodic spark plug maintenance is important. If a spark plug does not fire properly various generator issues will arise. If the spark plug is not replaced it will deteriorate over time and cause possible engine damage. Spark plug upkeep is key to good performance and fuel efficiency. The factory maintenance interval chart advise to check, adjust and clean the spark plug every 3 months or after 50 operating hours, whichever comes first. Replace a worn or damaged spark plug if necessary.
Spark plug service
Do not perform repair work or routine maintenance around the cylinder head until the engine has completely cooled down. Before the spark plug is removed, put on safety goggles and use compressed air to blow the cylinder head cover clean of dirt and debris that could potentially enter the spark plug hole while it is removed.
- Remove panel (12). See illustration.
- Detach spark plug cap and extract spark plug.
- Inspect spark plug electrode (1) for damage or wear. Check insulator color (2). The insulator should be brown or grayish-tan around the side electrode.
When replacing a spark plug be sure to gauge the opening between the ground electrode and centre electrode.
- Use a spark plug cleaner, wire brush or spray-on spark plug cleaner, if necessary.
- Use a feeler gauge or a coin-style spark plug gap gauge to measure gap thickness.
- Adjust gap if needed.
Before installing the generator’s spark plug, clean the plug surface and gasket surface. To prevent cylinder head damage, finger tighten (a) spark plug before using a torque wrench to tighten it to its specified torque (b).
- Install spark plug.
- Install spark plug cap.
- Reinstall panel (12).
Spark plug type
The manufacturer requires the spark plug to be replaced with a NGK BPR4ES standard spark plug. Do not install the wrong type of plug. A plug that is too long could result in serious engine damage.