Engine quits while running? This action induces a very high voltage in the secondary winding which causes a momentary spark to jump at the spark plug gap. STEP 1: Now the way we test this type of switch is to turn the switch in the off position once you have got your key switch inserted into the lawnmower switch and turn it into the off position. What Is the Function of Aircraft Magneto? interference. If its a misfire, just focus on the spark plug in question. The shorter the lead the higher the frequency, the longer the lead the lower the frequency. While holding the shim, turn the flywheel until the magnets are directly adjacent to the armature. CAPACITOR Working Principle Of Magneto Ignition System What is the Advantage of Magneto Ignition Your battery is the first link, and the spark plug is the final. STEP 2: Once you hear the clicking noise, proceed to the next step and you're going to put your digital multimeter. | Types of Boiler | Steam Boiler | How Boiler Work | Boiler Operation | Boilers Diagram | How Does a Steam Boiler Work, Governor Definition Engine | Definition Isochronous | Equation of Speed | Porter Governor Working | Porter Governor Construction, Cochran Boiler | Cochran Boiler Working | Working Principle of Cochran Boiler | Applications of Cochran Boiler | Advantages & Disadvantages of Cochran Boiler, Keyless Remote Battery Is Low | When Does Key Fob Battery Replacing Replacing? Radiated interference is that which is transmitted by electromagnetic fields and received by the antenna effect of other equipment. Conventional capacitors, because of their higher inductance, are less effective at attenuating interference than coaxial capacitors. Aflywheel with two strong magnets is used to create a magnetic field around the armature. Working of Magneto Ignition System : The armature is driven by the engine. Troubles with your motorcycles ignition? If the coil has been in service since the magneto was new there is a good chance the insulation has started to break down, allowing voltage to track. Pressure Vessels - Parts, Design, Application, Types, Material, Diagram. This expediential degradation may appear to be sudden when the fault occurs. The first thing to understand is that ignition problems come in a variety of shapes and sizes, and thats partly because different cars have different ignition systems and partly because there are various symptoms you may experience. It should be shielded to prevent low frequency (AM band) radio interference caused by voltage fluctuations within the coil's primary circuit. Dont start chucking wrenches yet, as no matter the type of vehicle you have, the basics of the troubleshooting system remain the same. Ignition harnesses Copyright 2023 Briggs & Stratton. Will you help me? Please refer to your operator's manual for more information, Old, damaged or fouled spark plugs can also require service or replacement, WARNING: Always read the engine and equipment manual(s) before starting, operating, or servicing your engine or equipment to avoid personal injury or property damage. Safety Warning: Stay clear of any rotating, moving parts, or other hazardous areas whenever attempting to start the engine or equipment. A helical conductor also reduces the level of RF radiation by returning more field energy to the conductor. All rights reserved. Dont worry, it happens to the best of us. If mounted on the firewall, the interference signals have to travel back through the firewall, engine mount, engine, and magneto. This is the Magneto that is used to produce energy but not for batteries. This article is an excerpt from the book "The Magneto Ignition System" by John Schwaner of Sacramento Sky Ranch. As with every how-to, that means there is some homework in order. A magneto is an engine driven device consisting of a rotating magnet and field poles. The condenser is used to eliminate the arching at the breaker points and intensifying the current in the secondary circuit. As the flywheel turns, the magnet spins around a transformer with exposed copper wire windings, inducing a current which fires the spark plug and ignites the gasoline. Difference Between Orthogonal and Oblique Cutting | Orthogonal Machining, What Is Cupola Furnace? Were here to be expert guides in everything How To related. However, typical signs of magneto problems are, among others: -- Bike hard to start. Step 3 - Check the Switch. Simply remove the coil wire from the distributor and leave it connected to the coil. At high Stress, a large amount of voltage is generated using a Step-up transformer that can be used for airplane engines and engines like the following Stress can manage this voltage so that it flows in the smallest part Wiring and also avoid leakage. In areas where these were not readily available engines used a so-called "low tension" magneto to feed the igniter points. For information regarding this, please visit our Inspecting the Flywheel and Key FAQ. If not, it needs to be replaced. On many Rolls Royce models there is a dual ignition system. The two magnetos on most GA aircraftthe left and the righteach fire one of two spark plugs on each cylinder. Over time the HT leads can degrade and reduce the potential difference at the spark plug. Inspect the harness for broken or frayed shielding wires. Without the grounding lead installed, you won't be able to turn it off. If you turn from Both to mag R, it will continue to run. Without the grounding lead installed, you won't be able to turn it off. 4. He majored in American history at Northwestern University. Youre going to have to figure it out ASAP. If you have points, youre checking the gap between the breaker points contacts. Testing & Replacing a Stop Switch The Magneto Ignition System is a unique kind of Ignition System which has its own source to generate the necessary amount of energy for an automobile or a vehicle to work. As the magnet spins (or the magnet rotor is turned), it generates a strong magnetic force that is "held back" by a primary coil. In spark-ignition engines, a device is required to ignite the compressed air-fuel mixture at the end of the compression stroke. The voltage generated across magneto coils is quite high, in the order of 20,000 volt if no spark plugs are in place. Your engine repair manual will provide the proper gap for your engine. It is better to connect the braid around the entire circumference so that the center conductor is surrounded. The central electrode is connected with the ignition coil supply. But you might find that youre 180 degrees out or that the distributor came off alignment due to a loose bolt on the hold-down clamp. This creates a spark. They also are common in antique motorcycles. Step 1: Clip one end of the spark tester (service part number 19368) to the ignition cable and the other grounded to the cylinder head as shown below. Remove the old ignition coil (armature) mounting screws, Disconnect the stop switch wire from the flywheel brake or other stop switch and remove the coil/armature, Attach a replacement ignition coil/armature loosely using mounting screws, Push the coil (armature) away from the flywheel and tighten one screw, Turn the flywheel so the magnets are on the opposite side from the ignition coil (armature), Place the appropriate shim between the rim of the flywheel and the ignition armature. A CDI ignition starts by generating a charge and storing it up before sending it out to the spark plug in order to ignite the engine. See TOOLS and MATERIALS LIST below.Subscribing to TheGarageEngineer YouTube channel is the best compliment you can give, http://bit.ly/2pvbuwvTOOLS and MATERIALS LIST:****Your purchases through the Amazon links below does not add to the items cost, but helps continue the making at The Garage Engineer. If the conductor is curved into a helical then some of the magnetic field returns to the conductor inducing a back current into the conductor. Armoto LtdRegistered & Trading Address:Unit 26, M1 Commerce Park, Markham Lane, Duckmanton, Chesterfield S44 5HSTelephone: 01246 826667 | sales@armoto.co.ukRegistered in England Company No. Copyright 2023 Briggs & Stratton. Locate the magneto. If you have an older car, youre likely going to be chasing wires. Because the fuel isnt burning, it will wash the cylinders and cause damage and eventually pollute the engine oil. Also, with the coil ignition unit, if the battery has gone down, the engine cannot be turned on until an additional battery is available. Just like with a chain, if any of the links fail, the entire system falls on its face. Check the connection of the high voltage, or HV, wire to the coil and to the spark plug clip if you obtain a reading higher than 15 k. After making sure the connections are clean and unobstructed, retest. The first one is known as the rotating armature type, and the other is known as the rotating magnet type. Look for approx. The ditto ridge is magnetized in the current main field direction, which is in contrast to the shallow tilt suggested by the study of the Deep Sea Drilling Project (DSDP) sediment core. At this point, weve checked everything, and we can almost conclude with absolute certainty that your ignition module, if present, is the issue. Today we will do a complete study about this system. Usually there are three bolts on the shroud, but some engines made in the mid-1970s have four bolts. You may have a similar issue if your battery isnt powerful enough to meet the demand of cranking the motor. The starter might be the reason you dont get spark during start-up. Readings are given in thousands of ohms, or "k" ohms. Locate the magneto. There are several design features used in ignition harnesses to lower How to Test the Ignition Coil in Your Small Engine. You can also test the flywheel magnets for any potential issues. For information regarding this, please visit our Inspecting the Flywheel and Key FAQ. If the spark jumps the tester gap, your ignition coil is working fine. For example, if youve just completed a project, likely, youve accidentally left something disconnected or bumped something along the way. Increased resistance or inductance lowers EMI. For more information, you can visit them online at www.sacskyranch.com. Verifying plug wires are in check is as simple as testing the resistance. While holding the shim, turn the flywheel until the magnets are directly adjacent to the armature, Loosen the tight screw so the magnets pull the ignition armature against the flywheel and shim. Remove the retaining nut from the end of the magneto and remove the gear. If you are experiencing ignition timing issues, this is most often due to a sheared flywheel key. When it does fail, it is usually due to heat caused from improper wiring of the ground wire to battery voltage. The capacitor is designed so that point wear compensates All Rights Reserved. Disconnectbattery ground first (if equipped). This is a low resistance value and emphasizes the importance of a good electrical connection to ground. Knuckle Joint Instantaneously, when the points open (separate) current flow stops through the primary windings of the ignition coil. | How Often Do Coolant Leaks Happen? Anaircraft magnetois an engine driven electrical generator that uses permanent magnets and coils to produce high voltage to fire theaircraftspark plugs. Like this post? Any signs of damage or decay are clear indicators that theyre your issue. On each rotation, an electromagnetic field is built in the coils on the armature. Note: if the gear has an odd number of teeth, the timing will change by 1/2 a tooth. But that doesnt mean you want to just spring for a new one. In other words, plenty of homework is necessary if you don't want to gamble on a replacement. Magneto Electrical A magneto is an electrical generator that uses permanent magnets to produce alternating current. It consists of a battery, switch, distributor ignition coil, spark plugs, and necessary wiring. Crank the Stihl equipment. Find The Magneto Coil Once the shroud has been taken off, you locate the magneto coil. Strong general magnetization is specified for high magnetic susceptibility and/or viscous remanent magnetization. Make sure that the ferrule used to install the lead into the magneto cap has pierced the plastic covering and makes contact with the steel braid. When you current the coil of an electromagnet (for example, with a battery), the coil creates a magnetic field in the armature. The distributor unit consists of a metals bowl with a central shaft, usually driven by a crankshaft or sometimes by a crankshaft. As the magnet spins (or the magnet rotor is turned), it generates a strong magnetic force that is held back by a primary coil. Engine oil can enter themagnetovia a damagedmagnetoengine oil seal. Make sure you do your homework to ensure you perform the proper test. Look for a crack in its enamel insulator, often lined with sooty deposits. Newer cars might need other tools and accessories. What Is the Difference Between a Magneto and a Distributor? It uses a magneto and a transformer to make pulses of high voltage for the spark plugs.The older term "high-tension" means "high-voltage".Used on many cars in the early 20th century, ignition magnetos were largely replaced by induction coil . Or that theres no power, but again, not why theres no power. For two-cylinder engines, you should test each cylinder to make sure you do not have a bad connection in the HV wires. The distributor is used in multi-cylinder engines to control the sparks in each spark plug in the correct order. If a four or six point EGT/CHT system is installed, note the cold cylinder. It will connect directly to the spark plug through a rubber casing. Alnico, the material most often used to fabricate early magnets has a tendency to lose its induced magnetic field over time due to various causes. It is a part of the electrical system which carries the electric current at the required voltage to the spark plug which generates spark at the correct time. This causes the magnetic field to collapse around the coil. If you do not have repair manual contact your local dealer for the correct specification. When positioned thusly, the dogs or slots on the mag should line up with the corresponding dogs or slots on the engine and slide right in. There is a possibility of misfire due to leakage because the variation of voltage in the wiring can occur. If all else in the system checks out, but you still dont have spark, the process of elimination tells us its the coil pack. | Cupola Furnace Design Cupola Construction | Purpose of Cupola | Working Principle of Cupola Furnace: | Advantages of Cupola Furnace | Disadvantages of Cupola Furnace | Applications of Cupola Furnace, Also, Read:What Is Sigma Comparator | Construction of Sigma Comparator | Applications of Sigma Comparator | Advantages of Sigma Comparator | Disadvantages of Sigma Comparator, Also, Read:What Is Forming | Types of Forming | Forming Process in Manufacturing | Metal Forming Processes | Forming Operations. )Items in videoAstro LED Mag work light https://amzn.to/32AeonjDielectric Grease https://amzn.to/2N4hImZSpark Plug tester https://amzn.to/2NSsrk7Spark Plug wire copper core https://amzn.to/2A1U4z5Multimeter https://amzn.to/34CMI2OKlein Self-adjusting wire stripper https://amzn.to/2TBVDQBWire terminal with heat shrink https://amzn.to/2u2HfRWSK socket set https://amzn.to/2u0RyGa3M Super 33+ electrical tape https://amzn.to/2ChayVwBottle LDPE varity fo sizes https://amzn.to/2M89fiTFuel line https://amzn.to/2YJ5fa4Marvel Mystery Oil https://amzn.to/2EuJT8BLong Reach Hose Grip Pliers https://amzn.to/30Eh4QRPermatex Ultra Grey RTV gasket maker https://amzn.to/2M5bXWvKnipex Diagonal/Side Cutters https://amzn.to/2ErIYG4RevMark variety pack markers https://amzn.to/2weAa1URev mark Black marker https://amzn.to/2M5XklO Shop toolsDelta Table Saw - https://amzn.to/2Cg3ZSVMakita Compound Miter Saw - https://amzn.to/2CiQuC0Weldbond Multipurpose Glue - https://amzn.to/2VSqJQjAstro 450 Lumen LED Light https://amzn.to/2TwMpovEVERYDAY CARRYLeatherman - Skeletool Multitool https://amzn.to/2Hwf1HdLUMINTOP ToolAAA flashlight - https://amzn.to/2tZUuCYKeychain Pocket Clip - https://amzn.to/2Ht9ZLFStanley 12' tape measure - https://amzn.to/2NWTtVxThe best advice I can to give is ABC Always be CuttingFOLLOW ME:Instagram: www.instagram.com/thegarageengineerFacebook: www.facebook.com/TheGarageEngineerYoutube: http://bit.ly/2pvbuwv (thegarageengineer)Website HQ: www.thegarageengineer.com A high-tension coil is a transformer the windings create a higher voltage through a secondary coil when the primary field coil circuit opens. The coils are the component that produces this high voltage. Find all Engine Safety Warnings. . Whether you start the engine with a pull rope or the turn of a key on an electric start motor, you're relying on the ignition system to produce a spark inside the combustion chamber. Armatures are often packaged with a thick piece of paper to assist in setting the gap. The ignitions system is the system that uses spark plugs as their source where electrical energy input is given to the spark plug. Dear Sachin, Thank you for the information. Be sure to unhook the coil from the equipment wiring harness as well as the engine's wiring harness and use the spark tester. The armature is driven by the engine. Amagnetois a combination of adistributorand generator built into one unit. Your engine, For information regarding this, please visit our. Whether you start the engine with a pull rope or the turn of a key on an electric start motor, you're relying on the ignition system to produce a spark inside the combustion chamber. Themagnetois a self-contained generator of high voltage that providesignitionto an engine through spark plugs. When you start your lawn mower or small engine, the rotation of the flywheel causes its magnets to pass the coil (or armature). affect ignition timing and hence engine performance. Sachin is a B-TECH graduate in Mechanical Engineering from a reputed Engineering college. Once you have confirmed that the stop switch is working, reconnect the spark plug lead. Let us start from the beginning. I would like to say thanks to you providing this article. Whether its a misfire or a no-run condition, you want to make sure that lack of spark is your issue. Batteries, having a definite shelf and usage life, often needed replacement. Make sure the coil grounding/kill wire is not rubbed through or pinched and shorting out against a piece of sheet metal, Attach coil wire to tester and tester to ground for this test, DO NOT attach to spark plug for this test as the engine may start. Because the ignition module is electronic and does not utilize moving components, it is normally one of the most reliable part of the engine. What Is the Main Disadvantages of the Magneto Ignition System? Check out our magneto armature winding service. Thats why its important to also be mindful of where you mount a canister coil under the hood of your car. The idea behind any ignition system is to generate an extremely high voltage at exactly the right time on the order of 20,000 volts. The main advantage of magneto ignition systems over other ignition systems is No external source is needed to generate this energy. Articles may contain affiliate links which enable us to share in the revenue of any purchases made. link to Pressure Vessels - Parts, Design, Application, Types, Material, Diagram, link to Knuckle Joint - Parts, Diagram, Design Calcuation, Applications, 3D Learn Mechanical Click here to Download From Play Store. (Current carrying conductors are low impedance and produce magnetic near-field radiation). | Cupola Furnace Design Cupola Construction | Purpose of Cupola | Working Principle of Cupola Furnace: | Advantages of Cupola Furnace | Disadvantages of Cupola Furnace | Applications of Cupola Furnace, What Is Sigma Comparator | Construction of Sigma Comparator | Applications of Sigma Comparator | Advantages of Sigma Comparator | Disadvantages of Sigma Comparator, What Is Forming | Types of Forming | Forming Process in Manufacturing | Metal Forming Processes | Forming Operations, What Is Boliler? Place the appropriate shim between the rim of the flywheel and the ignition armature. Both the systems work on the principle of mutual electromagnetic induction. Common armature gap ranges are .006 - .010" and .010 - .014". A capacitor discharge ignition works by passing an electrical current over a capacitor. 300 to 380 ohms across blue and black wires, .25 to 3.25 ohms across white and black wires. Troubles with your motorcycles ignition? To get your magneto to mesh to the engine, you must turn the magneto (in the direction it was designed to operate in) until the rotor is positioned over the number 1 plug wire terminal. A magnethencemagnetospins in close proximity to a coil of wire. In modern designs of the magneto, more recently, very light and compact units can be made using cobalt steel and nickel aluminum magnet metals that occupy very limited space. Your engine repair manual will provide the proper gap for your engine. Unlike a dynamo, amagneto does not contain a commutator to produce direct current. than on the firewall. Main Parts of Magneto Ignition System 1. Compression and fuel are necessary to get the engine running. No spark, poor spark or performance? Learn how to test them properly. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); At Mechanicaljungle, we clarify Mechanical engineering and publish all the happenings & news of Mechanical engineering. In the battery ignition system, the current in the primary winding is supplied by a battery whereas it is supplied by a magneto in the magneto ignition system. Shields also intercept radiated noise and return it to its source through a low impedance. To best determine the cause of failure, please consult an Authorized Dealer. Additional questions? Options for fixing this are to buy a new magnetoor to send themagneto to a business that specializes in restoration. You can also test the plugs resistance to verify that its capable of supplying a strong spark. Automatic time adjusting of ignition can be affected. Announces Executive Leadership Changes, Kansas City Area Business Illegally Supplied Russians With Aviation Tech: Prosecutors, Saudi Arabia To Establish 15 New Plants for Medicines, Aircraft Parts, and Metal Forming. Amagnetois an electrical generator that uses permanent magnets to produce periodic pulses of alternating current. So lets get started. It is an electromagnetic device that converts a low tension (LT) current from a battery to a high-tension (HT) current each time the distributors contact-breaker point is opened. To further complicate things, the root cause in either situation isnt always the same thing! SPARK PLUG 4. The cam then breaks contact with the armature and the electromagnetic field regenerates for a new pulse of electricity. These include using a conductive shield, increasing copper content of shield conductor, increasing lead inductance, and increasing lead resistance. The ignition system is intended to generate a much larger volt lifespan from the cars 12-volt battery and to send each sparkplug in turn, igniting the fuel-air mixture in the engines combustion chambers. Remember, the resistors job is to lower the voltage coming in. You are also working with a high-voltage system. Set the multimeter into the ohms function, or just use an ohmmeter. Thereforemagneto ignition is very popularly used in racing cars. Instead, if possible, youll want to test the ignition module to verify its the issue. Ignition filters 7. Back in 1897, Bosch probably could not have anticipated the success that the magneto would one day enjoy. If nothing is obvious, you can test the plug with your multimeter. Were going to do our best to help you figure out what your problem is so that you can get on to the proper repair. The shielding needs a low impedance path to ground at both ends with the ground at the magneto end being the most important. The working principle of the ignition system is similar to Except the working principle of the coil or battery ignition system. In this video, I show you how to replace the ignition switch in your MGB. Magnetos that are adapted to produce pulses of high voltage electricity are used in the ignition systems of some gasoline-powered internal combustion engines to provide energy to the spark plugs. This type of ignition builds up a charge quickly. The Ultimate Troubleshooting Guide for AIrcraft Magnetos 918-835-6948 TUL: 5746 E Apache St. Tulsa, OK 74115 FXE: 2199 NW 53rd Street Fort Lauderdale, FL 33309 sales@qaa.com Ultimate Magneto Troubleshooting Guide How to diagnose your magneto/ignition system issues Amagnethencemagnetospins in close proximity to acoil of wire. Step 1 Place the Stihl tool on a sturdy work surface. Rubberized gloves ready? Themagnetois a self-contained generator of high voltage that providesignition to an engine through spark plugs. The shield surface reflects interference energy because of the impedance discontinuity at the shield boundary. We help brands optimize their online presence & performance. Got a pro tip? How Does the Magneto Work with the Flywheel? A magnet consists of five parts: An armor. You can overheat your coil. Testing a coil pack is made simple with the spark plug tester. So youll want to keep these safety tips in mind to avoid any unpleasant experiences. Stay clear of any rotating, moving parts, or other hazardous areas whenever attempting to start the engine or equipment. Comment below, and lets talk! As you can guess, the values youre looking for depending on the manufacturers spec. Harnesses with plastic covering over the braided shielding may prevent the shielding from grounding to the magneto cap. Do not use auto ranging, as it is unreliable with a magneto. The sharp voltage pulse also creates more EMI since the noise component of the pulse is the rise-time. Thats exactly why troubleshooting is so important. There are two types of distributors. If not, it needs to be replaced. Safety Warnings: Shielding sets boundaries for radiated energy through reflection or absorption. The cap and rotor contain your contacts that are responsible for sending spark to the cylinders. Ignition filters are used to suppress radio interference from the "P" lead. Pull the rubber casing off the spark plug. The magneto is the white blocks in the following photo (this is the magneto for the series): The idea behind a magneto is simple. A compression ignition engine, i.e. Magnetos Under Pressure. Remove and inspect your spark plug. A series of rotating magnets break an electrical field, this causes an electrical current in the coils primary windings. It will connect directly to the spark plug through a rubber casing. With older coils, winding insulation break down or . If the air gap is too small, you need to replace the magneto or the engine. -- misfiring, particularly at higher revs and fully open throttle, or when opening the throttle. With an electronic setup, youll need to take the time to make sure the gap between the magnetic pickup and reluctor wheel is to spec. (a) Adjustment of spark timings adversely affects the voltage. Trace the ignition lead back to the magneto . Coaxial capacitors are more effective at radio frequencies. | How to Replace a Keyless Remote Battery. So let's get started. Youll also need to make sure themagneto is reinstalled properly. Magneto ignitionsystem is anignitionsystem in whichmagnetois used [produces high volatge] for the generation of electricity and further that electricity is used in several things like to run the vehicles. Oil seals are known to deteriorate with age, operating hours in service and exposure to heat, including hot engine oil. Required fields are marked *. If magneto coil is known good and still no spark then go to step # 6. As the speed increases, the voltage in the primary winding also increases rapidly and the Intensity of spark is also higher and provides better combustion, as compared to the battery ignition system. An example is the 440 in my project Charger were probing today uses an electronic system that features a magnetic pickup. Your process may be similar, but youll want to verify with the manufacturer of the distributor. 30,000 volts. Oil contaminationcausessuch magnetos tomalfunctionandfail. At medium and high speeds, it is more efficient. Pull out the ignition switch: Lift the hood and find the locking tabs located at the back of the ignition switch. Learn how to properly and safely use, troubleshoot, and maintain your lawn mower, tractor, snow blower, and other lawn and garden equipment. It produces pulses of high voltage for the spark plugs. Please Give more information about it. Ground the "P" lead shielding to the magneto to keep the ground path back to the magneto as short as possible. Ignition filters change the capacitance of the coil's primary circuit. With the T-118 inserted (Figure 5),. LOW TENSION MAGNETOS. A good RF-shield connection is below 3 milli-ohm resistance. You can also apply a conducting grease (Penetrox) to the contact surfaces. If the tip looks black, bent or broken in any way, replace the spark plug. iii. Release the tabs and push out the switch. How Does the Magneto Ignition System Works in Aircraft? Spark plugs typically have two electrodes that are separated from each other. A shielded lead, if it is not properly grounded, can resonate at radio frequencies and become a dipole antenna. Vacuum leaks can wreak havoc on your engine and even prevent the engine from firing off. A cam on the electric unit creates contact with the armature, disrupting the field and creating electrical voltage in the primary coil. You can also shout at us on Twitter or Instagram, here are our profiles. Solid-state systems: the more modern option, these systems use a tiny transistor in the coil or armature to close the electrical circuit that travels through the spark plug lead to the spark plug(s).