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5 Tips to Keep Spark Plugs Performing in Any Engine

Though the diesel engine is the main worker on the farm, there are numerous gas power plants toiling away that also need maintenance. One crucial component, the spark plug, is often ignored, which has a huge effect on engine operation.

A spark plug appears simple in design and operation, and it is often taken for granted and is the recipient of improper service. Residing in the combustion chamber, a plug endures severe temperature fluxes, extreme pressures, electrical degradation, and chemical attack from the components blended into the gasoline. Despite the environment, the spark plug can deliver a very long life, if installed properly.

Here are five simple tips to keep a plug performing in any engine.

1. Clean before removing the old spark plug.

Before removing the old spark plug, use a compressed air gun to blow away any dirt or debris that may have collected around the exterior. The dirt cannot be allowed to enter the cylinder bore because it will score the wall and wear the rings. If the spark plug does not have a tapered seat, then a washer-style gasket is required. The gasket is installed with the small side toward the cylinder head. The length of the threaded area is called the reach and positions the electrode properly in the cylinder bore.

Spark plug electrode
2. Always inspect a new plug for damage.

If dropped, check for cracks in the porcelain. Make sure the side electrode lines up with the center electrode and is straight. If not, gently reposition it with needlenose pliers. Next, employ a spark plug feeler gauge to obtain the proper gap between the electrodes.

When correct, the gauge will drag evenly on both the center and side electrodes. Make sure the gauge is straight and not cocked when checking. If the side electrode needs to be excessively angled up or down to create the proper gap, the spark plug is of the wrong design or the specification is incorrect.

Spark plug cleaner
3. Spray the cavity around the center electrode.

Using carburetor cleaner, spray the cavity around the center electrode while having the plug face downward so any material will fall out.

This will remove any porcelain dust or debris from manufacturing that can cause a misfire, especially under load.

Spark plug anti-seize compound
4. Coat the thread with antiseize compound.

This is especially important with an aluminum cylinder head or equipment that is not stored in a building. This will aid in removing the plug in the future without galling the threads in the cylinder head.

Keep the antiseize compound away from the electrodes. If it gets on the electrode, wipe it off with a clean rag that is moistened with carburetor cleaner.

Spark plug dielectric compound
5. Coat with dielectric compound.

Coat the secondary wire connection and the porcelain insulator where the boot sits with dielectric compound (available at most auto parts or farm supply stores).This compound deters corrosion and prevents the boots from sticking to the insulator, which can lead to wires breaking during future service.

Thread each plug in by hand and then tighten with the proper socket and wrench. The plug needs to be tight against the cylinder head to maintain heat transfer and to keep the bore sealed. Never use air tools to remove or to install a spark plug.

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