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Guide to Generator Spark Plugs

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Without spark plugs, your generator will not be able to function properly. So, let's get into the nitty-gritty of spark plugs so you know everything you need to.

Generator maintenance

Keeping to a few basic guidelines will make maintenance scheduling for generators a breeze. The answer to this question will shed light on how frequently the generator is used, how often maintenance should be performed, and what else has to be done.

Generators that are used regularly will need maintenance more often than those that are only used occasionally. However, all generators, regardless of how often they are used, require some level of routine maintenance.

It is imperative that generators are serviced annually and checked for leakage.

Oil should be changed every 50 to 60 hours to ensure reliability.

It is recommended that oil filters be changed at each oil change to ensure that the new oil is being filtered properly.

As clogged air filters won't be able to draw in enough clean air, they need to be changed annually.

A thorough examination of the battery's power output and condition is not required. Make sure there is no rust or corrosion on the battery or any of the connections.

Spark plugs should be changed every 100 hours of operation. Spark plugs should be checked for cracks and corrosion during routine generator maintenance.

These tasks must be done on a regular basis, the frequency of which will vary based on the generator's usage and kind. The manual will have maintenance recommendations for your specific generator model.

Are all spark plugs the same?

NGK Spark Plug, NGK BKR5E-11, ea, 1, One Size

Because not all vehicles require the same specifications for their spark plugs, it's best to buy them in sets. Depending on the use, spark plugs can be found in a wide range of metals, diameters, and gap sizes. The right ones could be hard to find.

Standard spark plugs and performance spark plugs are the two broad categories into which spark plugs fall. Manufacturers aim for optimal combustion when designing performance spark plugs.

The spark plug's longevity is increased by the use of particularly hard metals for the tab that the electrode arcs to during combustion. What sets these apart from regular spark plugs is this. Single-tab, double-tab, and even four-tab designs are available for high-performance ignition systems.

A spark plug's "heat rating" indicates how quickly it dissipates heat after being ignited. Hot plugs, similar to high-performance spark plugs, increase the ignition temperature to their maximum to produce the most efficient combustion possible. Hot spark plugs are a popular upgrade for high-performance vehicles. 

When it comes to spark plug electrodes, every metal choice offers its own set of benefits. In contrast to platinum and iridium, copper has excellent conductivity but is not as hardy.

A significant advantage in conductivity is shown in spark plugs made of copper, which is why manufacturers produce them. The 2.5 mm center electrodes typically come from nickel alloy production.

Double platinum spark plugs have a third electrode that allows the spark to leap from the center electrode to the outside electrodes. The electrodes are designed such that sparks can travel in both directions without rapidly degrading the electrodes. This allows the spark plugs to retain their initial effectiveness over time.

Iridium spark plugs are commonly constructed with "fine wire" centers and 4 mm electrodes. Due to their thin wire centers, iridium spark plugs often have the highest firing efficiency.

Why do spark plugs sometimes not work?

4 PK TORCH F7TC Spark Plug Replace for NGK 3785 BP7ES Spark Plug, Compatible with GX120 160 200 240 270 340 390 Generator Lawnmower Tractor Go Kart Mini Bike Polishing Machine 168F 168FA 168FB, OEM

Because spark plug spacing and lengths vary, it's important to purchase the right ones when you need to replace them.

Overly lengthy spark plugs might damage the piston if they protrude too far into the cylinder. Meanwhile, an engine that has spark plugs that are too short may have problems starting and will regularly misfire.

Spark plugs can become less effective at their job when a generator ages, wears out, or experiences issues with the electrical or ignition system. The ability to ignite the air-fuel mixture and transmit heat out of the combustion chamber can be "fouled" if they overheat, burn, or get contaminated.

As the gap widens between the plug's electrodes over time if they aren't replaced, the spark has to "jump" farther to ignite the fuel. Over time, this chasm may expand, leading to erratic or inefficient combustion.

How to spot spark plug issues

Ignition Coil + Spark Plug Replacement for Champion Power 196cc 6.5HP 3500 4000 Watt Gas Engine Generator

Given the importance of spark plugs to your generator, it's not surprising that the signs of a failing set can be concerning. 

The following are some examples of common warning signs.

Noises that ping, rattle, or knock. Once spark plugs begin to misfire, the force of the pistons and the inefficient combustion can cause some really peculiar noises. The pistons allow for rapid acceleration. The spark plug could be firing at the wrong time, causing the engine to make a constant rattling, pinging, or knocking sound.

Generator starting problems. If your generator is difficult to start or looks jerky and uncoordinated, it may be because your spark plugs are not functioning properly, which can lead to misfires and erratic performance.

Decreased efficiency. If the spark produced by this little plug isn't working at full capacity, your generator won't operate as well as it could. Meaning you could see surges or power drop outs with your generator. 

Not very efficient with petrol. Spark plug malfunction is one of the numerous causes of low fuel economy because it prevents the engine from producing a spark at the optimal time.

If you see any of these symptoms, it's best to have an inspection done on your generator before the problem gets worse. Spark plugs are a vital component to the starting and continued operation of your generator.

Spark plug replacement

The following is a guide on how to replace the spark plugs in a generator:

Find the spark plug

The first and sometimes hardest step is locating the spark plug, which is especially true for first-time mechanics. It is usually covered by a spark plug boot and tucked away inside a removable housing.

We found that the quickest way to locate the engine's spark plug was to locate the black cable that was attached to the engine and ended in a boot.

If you can't seem to locate the spark plug, check the manual. It could provide us clues about its possible hiding places and how to best approach it. In addition, more powerful versions and some brands may have more than one spark plug.

The handbook for the generator should therefore be read thoroughly before usage.

Disconnect the plug wire

Once you've located the location of your old plug, you can remove the cord connecting it. To do this safely, you'll need to get your hands on a spark plug wire's boot.

To remove the boot quickly and easily once you've gained access, grab it firmly, twist it in any direction, and pull it off quickly.

Even if the wire has been slightly corroded, you should be able to tear it free using this method. By rotating the wire in a circle, you can release the clip that holds it to the spark plug with less effort, reducing wire tension.

Remember that if you tug on the wire part, you risk breaking it.

Be a clean freak

After disconnecting a wire, you should thoroughly clean the plug and the area around it. 

Cleaning the generator thoroughly is an important task that should not be skipped.

Once you pull the plug, you'll have unrestricted access to the engine. Dirt will inevitably do harm once inside.

Debris, grime, and oil slicks can accumulate, so it's important to remove them and clean the area thoroughly.

Remove the spark plug

Once you've made sure nothing can fall into your engine, you can begin removing the old plug. 

You'll need a ratchet and a spark plug socket of the right size.

Generally, we've found that sockets are either 3/8" (14 mm) or 5/8" (16 mm) in diameter. The owner's manual usually provides this information. 

After firmly positioning the ratchet on the spark plug, the spark plug can be loosened.Socket rotation accomplishes the remaining threading and unscrewing. Once sufficiently loosened make the final rotations by hand to remove it. 

If you try to remove the socket by tilting it, you can break the plug.

After removing the old one, you'll need to free up the socket so you can put in the new one.

Inspect the new spark plug

Before you put a new spark plug into your generator, double-check that it is the right make, size, and gap. It is recommended that you use a gap measuring instrument for this job. This is a cheap and useful tool to have in your tool box.

This tool is used to measure the arc of the spark plug's tip, where two electrodes (one straight and one curved) meet.

This too works by pushing the feeler gauge into the area until you can freely move it around but start to feel some resistance. It can't be too snug or too free. As soon as you have the reading, compare it to the value given in the instructions. If both numbers are the same, then you may proceed to the next section.

If you are still unsure whether or not you have the proper plug, you should consult the professionals at your local hardware store. They will be eager to be of service to you.

Change the plug

After checking the gap and making sure it is correct, you can proceed with plug installation. Take the new spark plug, then place the socket into the corresponding open socket on your engine.

Once it is properly placed in the hole, you can gently spin it with your hand to tighten it. There shouldn't be any major resistance or difficulty.

Now is not the time to risk cross-threading your plug. Take it out and try re-inserting it if there is any resistance. If you are able to manually spin it and meet no resistance, continue doing so until you are unable to.

After that, a ratchet can be used to tighten it fully. Be cautious about going too far, though.

Reconnect the wire

After the new spark plug has been securely placed, the wire must be reconnected. It's time to grab the spark plug wire boot again and slide it over the top of the plug. Continue pressing it in until it is completely seated.

It's common to hear or feel a click as the connector locks into place. You're good to go once you've replugged everything and replaced any removable covers.

It's important to give your gadget a "test run" to ensure it's working properly.

Final thoughts

If you need help with your generator, read the manual that came with it. Don't toss it out until you've read it since it contains vital details.

Spark plugs are usually covered in detail in the upkeep chapter. Usually, the make and model number of the item are specified. You'll find gap measurement details and other tips for picking the right spark plug in the maintenance section of your Owner's Manual.

If you're not confident in your ability to choose the right spark plug for your generator, it's best to get some expert advice. As opposed to causing irreparable damage to your engine, admitting you need help is the best option.

Spare spark plugs should be kept in stock at all times. Since these components are inexpensive and stable over time, you can afford to stock up on a few in advance.

Having lost power and having a damaged spark plug can make it difficult to locate the appropriate model in your area if the generator starts to fail.

Also, once hurricane season starts, it can be difficult to find spark plugs in general.

To get help, just contact a local dealer or distributor of your chosen generator brand.

About Tom Bell

Hey, I’m Tom, the owner of Generator Reviews! I built this website to help you get the very most out of your generator and select the correct one for your personal circumstances. This site contains reviews of virtually every generator, detailed buying guides, as well as maintenance advice to help you keep yours in tip-top shape!


Generator.Reviews is an independent review business. I am not affiliated with any manufacturers and do not accept paid reviews. When you buy through my links, I may earn a commission which helps me to maintain this website and keep the reviews coming your way!

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