Bob Beecham | Updated 12:07 PM, March 30, 2021

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The working principle of the spark plug is to take a small amount of electric charge from the ignition coil and pass it through two electrodes. The difference in charge at each electrode point generates sparks. In turn, this ignites the fuel and the engine runs.

In riding lawn mowers, such sparks occur thousands of times per minute, so it is not surprising that spark plugs will eventually wear out as the electrodes become gray or burnt. At first, the difference is so small that it will not be noticed, but in the end performance will deteriorate. The lawn mower becomes more difficult to start. Or worse, on the day you tidy up your yard for your first summer picnic, it won't even start at all. It coughs and sneezes, and may smoke more than usual, all of which indicate that it is time for a change.

To help you decide which spark plug is right for your lawn mower, read on to learn about many important features to consider. Also, check out the spark plugs below, they are some of the best spark plugs on the market and can be used as a substitute for riding lawn mowers.

Although it is possible to replace old spark plugs of the same type or use the user manual of the riding lawn mower to find the best spark plug, remember that the manual contains the best spark plug available at the time the manual was created. If the lawn mower has been in use for several years, improvements in spark plug technology may make other options feasible. The following information explains spark plug technology in detail so that you can make an informed decision to buy the best spark plug for your riding lawn mower.

The type of spark plug is usually defined by the material used in the electrode: copper, platinum or iridium.

The length of the part of the spark plug that appears on the outside of the engine is rarely important, but the diameter and length of the threads inside the engine are critical. If the diameter is wrong, it doesn't fit at all: it either won't screw in, or it's too loose. If the length (also called range) is wrong, it may still fit, but there may be other problems. If the time is too short, the spark will not be in the correct position in the combustion chamber, and the motor will not operate normally, or even at all. If the time is too long, the piston is likely to hit the spark plug, causing serious damage. Due to these facts, it is important to check all dimensions.

The electrode gap has an impact on performance. When making spark plugs, the manufacturer should set them accurately, but they will become larger with wear. Historically, this gap was checked during maintenance and the gap tool was used to adjust the outer electrode. Vehicle tuners may still do this, but most lawn mower owners only need to replace new spark plugs; some spark plugs cannot be adjusted anyway.

Recent innovations have also resulted in a new design of the shape of the outer electrode. The goal is to produce a more precise spark, so as to burn the fuel and air mixture more efficiently. The price is still competitive, and it is an increasingly popular choice for those looking for the best spark plug for riding lawn mowers.

Spark plugs can also be described by their heating range. They are hot swappable or cold swappable. Generally, engines with moderate performance use hot plugging to achieve better fuel ignition, while high-performance engines use cold plugging to improve heat dissipation.

This is another area where wrong choices can cause problems. There is a misunderstanding that a hotter plug can improve performance. However, if the plug runs too hot, the insulating layer around the center electrode may melt. At best, this can lead to irregular shooting. In the worst case, it will break away from the spark plug and damage the piston. Spark plug manufacturers usually have comparison charts of other manufacturers' products, so you can check the thermal range and the physical properties of the spark plug.

Ignition circuits that allow plugs to spark can also cause electromagnetic interference (EMI) and radio frequency interference (RFI). These will actually destroy spark performance. To prevent this, a suppressor is used; it is usually built into the insulating layer around the center electrode. The purpose is to make the lawn mower engine run more smoothly. Although it usually exists, it is a feature that is not often mentioned.

Manufacturing standards help support any quality claims that the company may make in spark plug packaging and advertising. Both SAE International (formerly Society of Automotive Engineers) and ISO (International Organization for Standardization) have established spark plug standards, which have a wide range and high technical content. Many spark plug manufacturers meet these requirements and may even declare that they meet these requirements. It is important to understand that these standards organizations cover manufacturing quality and accuracy, not any performance characteristics.

Now that you know more about durability and performance options, it's time to take a look at some of the best spark plugs currently available. These are not particularly expensive, but the designated categories provide a quick and easy reference for each type.

The American company Champion has more than 100 years of experience in spark plug manufacturing. The Copper Plus model provides reliable performance and value for money. The Copper Plus 71 spark plug has a special body corrosion-resistant coating, and patented RFI and EMI suppression help the engine run more smoothly. Compliance with SAE and ISO production standards emphasizes quality.

The range of spark plugs used in riding lawn mowers and lawn tractors is very wide. Although many spark plug companies produce a limited range of garden machinery, Champion usually has suitable alternatives, regardless of brand and model.

People may be reluctant to buy low-cost consumable engine products from overseas. Although the price seems to be a bargain, if the components do not have the required quality and durability, then any savings will become a false economy. Fortunately, this is not the case with the excellent Maxpower spark plugs. Although it is always important to check the specifications, these specifications are designed for popular riding lawn mowers from brands such as John Deere and Husqvarna, and are also suitable for many Kohler motors.

It is a basic and simple copper spark plug, so it will not compete with platinum or iridium models in terms of life expectancy. However, it does produce a reliable spark, and its price is only about half of similar "big-brand" copper substitutes.

The core of the E3 lawn and garden spark plug is a copper model, but it has a unique outer electrode shape that surrounds the center electrode. This aims to provide a more precise spark, thereby increasing fuel consumption while significantly reducing emissions. It also reduces the accumulation of carbon deposits, thereby extending durability. DiamondFIRE technology is very unusual and has been patented.

E3 spark plugs are suitable for various four-stroke riding lawn mowers and lawn tractor motors, and two-stroke models are also available. Although more expensive than many competitors, the performance and fuel efficiency improvements of this spark plug will far exceed the service life of the spark plug.

Briggs & Stratton motors are suitable for many of the best riding lawn mowers. Although multiple brands of spark plugs can be used as substitutes, sometimes the original brand is just the spark plug best suited for the job. This highly durable platinum model can also be fitted with many other L-head (or flat-head) engines. This design is popular on riding lawn mowers due to its compact size.

Compared with ordinary copper spark plugs, the increased cost should be balanced with consistent performance throughout the extended service life. This usually leads to better fuel economy and, depending on the model, to ensure compliance with EPA emission regulations.

Fram's Autolite Xtreme Performance brand uses electrodes made from a combination of iridium and platinum. The benefits are precise spark generation and excellent durability. The tip of the center electrode is only 0.6 mm (0.02 inch) wide, which helps to place the spark in the best position in the combustion chamber. It is supported by highly wear-resistant patented platinum side wires.

There is some debate about whether relatively low-performance engines (such as those installed on riding lawn mowers) really make full use of iridium technology. However, the competitive price of Autolite XP spark plugs makes them an affordable option.

Spark plugs, like oil changes, are part of the regular maintenance of any engine. However, this may go unnoticed, which can damage the vehicle. Choosing the best spark plugs for riding lawn mowers and replacing them regularly makes financial sense and provides many additional benefits:

This guide details the technical aspects of the best spark plugs for riding lawn mowers, combined with reviews of some of the top models currently available, which may help to better understand these devices. If you still have questions, the answers to some common questions below may be helpful.

There are two ways to look at this problem. Yes, the type of spark plug is important because the motor depends on a certain size and type to operate effectively. However, as long as the size and specifications are correct, spark plugs from manufacturers other than the original equipment manufacturer can be used. If compatible, platinum or iridium alternatives can also be used instead of copper spark plugs.

The manufacturer usually provides guidance in the user manual. For copper models, replacing the spark plugs every season is usually sufficient, but other models may last longer. It is difficult to give an accurate estimate, because it largely depends on the frequency and time of your mowing and the working intensity of the motor.

Difficulty or failure to start is a symptom of spark plug failure. Engine misfire or excessive exhaust fumes are common indicators.

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