How To Check Spark On Trimmer Candle

An element in the device of a gasoline engine is a spark plug. In simple words, she is engaged in the ignition of the fuel-air mixture in the cylinder combustion chamber.

Spark plugs. What is it?

Spark plugs. A device that performs the function of providing ignition of the fuel mixture. Depending on the design of the engine, different candles are used: spark, glow, arc, catalytic, semiconductor, plasma.

Spark plugs are used in gasoline-powered automobile engines. In diesel engines, glow plugs are used. The rest are used in different thermal motors.

How to check spark plugs yourself

There are several ways to check for a spark and, in general, performance:

  1. Start the engine and alternately pull out the high-wire wires from the candles. If the candle does not work, then the sound and vibration of the internal combustion engine will not change. And, if you disconnect the wire from the working spark plug, then you will immediately feel changes in the operation of the motor.
  2. Stop engine. Unscrew the candle, put the thread on the body, for example, on the valve cover, and, the second person turns the ignition key. The one who holds the candle, it is better to keep it in rubber gloves or even let go. His task is to see if there is a spark, and what it is.
  3. Special device for checking candles. A gun. A candle is inserted into the gun and it is determined whether or not there is a spark.
  4. A homemade device for checking candles. A piezo lighter with a wire. Connect the wire from the piezo-lighter module to the removed candle and put the piezo-lighter block on the “mass”, then press the button on the block.
  5. There is another way to check the pressure. But, why use all sorts of complicated methods when the first two methods for checking spark plugs are the most effective.

How to check a spark

From time to time it is necessary to check the performance of the candles in order to find out some reasons for the unstable operation. There are 3 ways to test spark plug sparks:

  1. Check for weight.
  2. We check with an electronic measuring tool (multimeter).
  3. Manual mechanical army spark test method. The essence of the method is to make a clearance of 4 mm. If the spark hits exactly in the middle, then this is a perfectly working candle. If with such a gap the spark hits in the side, then this is already a poorly working candle.

Signs that you need to check the candles for sparks:

  • Interruptions at idle;
  • Ice tripling;
  • Twitching while moving;
  • Increased fuel consumption.

Why there is no spark, reasons:

  • Filled the candles;
  • Broken high-voltage wires;
  • Broken contact;
  • The crankshaft sensor is out of order;
  • The ignition module is out of order;
  • The ignition coil (bobbin) is out of order;
  • The switch is out of order;
  • Faulty distributor;
  • The service life has ended (usually a resource of up to 50 thousand kilometers);
  • Large layers of soot on the electrodes of candles (due to low-quality fuel and excess)
  • The presence of oil on the electrodes (excess oil and worn rings);
  • Varnish and slag deposits on the electrodes (due to various additives in oils and fuels);
  • Molten candles;
  • Mechanical damage to a compound candle;
  • The “mass” contact is bad;
  • The electronic control unit (ECU) is working with errors.


It is possible to simplify the work with candles by observing a simple recommendation. To change the spark plugs according to the schedule, the service life. This is usually for gasoline ICEs about 30 thousand km.

One of the methods for checking candles on.

General recommendations for the operation of candles.

Spark Test on Injector Motor

Among the common malfunctions of an injection engine or carburetor engine is one where a spark has disappeared from the spark plugs. In this case, the engine may not start or, after starting, function intermittently (troit), since one of the candles does not have a spark and the cylinder actually does not work.

In such a situation, diagnosis should begin with a check on the ignition system. In parallel with this, it is worth considering certain features and nuances, depending on the type of engine installed. Next, we will talk about the available methods for checking spark ignition for engines with a carburetor, and also consider what to do if the spark on the injection engine has disappeared.

Why the spark disappears: the main reasons

On different types of engines there is a fairly wide list of reasons why there is no spark on the spark plugs. Among the main experts distinguish:

  1. Problems with spark plugs (destruction of the spark plug body, electrode defects, etc.). It is also worth noting that the candles can be filled with fuel or oil, which indicates a breakdown of the engine itself.
  2. Malfunctions of high-voltage wires associated with breakdown of insulation or lack of contact.
  3. Failure or errors in the operation of the crankshaft position sensor.
  4. Problems with the ignition module, ignition coil, switch;
  5. Failures or malfunctions of the distributor.
  6. Deterioration or lack of contact of the “mass”.
  7. Errors associated with the operation of the electronic engine control unit (ECU);

There is no spark on the injection engine or carburetor engine: how to check

Spark testing is possible using several methods: to “mass”, by using a multimeter, a special tester on a piezoelectric element. The first method is the easiest. The body of the twisted out candle is brought to the metal (usually this is the engine block of the engine), after which the motor is scrolled by the starter and the presence of a spark is analyzed.

Please note that the specified verification method cannot be used during the diagnosis of injection vehicles. The fact is that on a car with an injector there is an ECU and other electrical equipment that is quite sensitive and can be disabled.

The second method allows to evaluate the condition of the spark plug to a greater extent, to identify breakdown, etc. The use of a special tester is a method of checking sparks on an injector car, reminding by its principle a test by analyzing the breakdown of a spark for “mass” (the first method). In this case, the risk of burning the control unit is minimized. Now let’s talk about how to test a spark on an injection engine.

The complete absence of sparking indicates possible malfunctions of the controller, ignition module, malfunction of the coil or central wire. Diagnostics should be started by checking the fuses. Then you should evaluate the state of the “mass” contact, and also check the high-voltage wires.

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If there is no spark on the ignition coil, then the performance of the high voltage wire should be diagnosed. The specified wire should be checked for insulation integrity, not have breakdowns, charred areas, etc. The detection of any defects is the basis for its replacement.

Also, in the process of diagnosing the ignition system, inspect the spark plugs. This should be done if electricity reaches the candles. On carburetor cars, it is enough to remove the spark plug wire, and then bring it closer to the metal surface (for example, the car body) by half a centimeter. Then you need to twist the starter and make sure the presence or absence of a passing spark between the wire and the metal surface. The spark itself should also have a certain intensity, be white with a slight bluish tint. If deviations are not noticed, then the candles are working. The reason that there is no spark on the candle may be the ignition coil.

If problems with candles are noticed, then you need to pay attention to the contacts of the candles. These contacts must not be contaminated. We add that, if there are deviations from the norm, it is optimal to immediately replace the spark plugs. The lack of such an opportunity will indicate the need to clean the contacts.

Spark ignition coil test

To diagnose the coil performance, remove the wire from the distributor-breaker. Further, the check is carried out similarly to testing high-voltage wires, that is, the wire is brought to a metal surface and twisted with a starter. The presence of a spark in this case will indicate a malfunction of the ignition distributor, if there is no spark, then the problem is in the coil.

First, check the distributor contacts. These contacts may oxidize, insulation damage may also occur, and the rotor itself may also be faulty. Detecting problems with the rotor can resolve the problem by replacing it. During the test of the ignition coil, possible defects in the integrity of the winding, burnout and other signs that a short circuit is occurring inside should be identified. If such signs are detected, the coil should be replaced or the ignition coil should be repaired.

Now let’s take a closer look at ways to test the main elements of the ignition system. To do this, back to the coil. As already mentioned, the most common cause of a malfunction is a damaged winding. Then there is a breakdown of insulation and a short circuit occurs. It is also important to understand that the coil may fail due to overloads. Such increased loads result from problem candles or candle wires. For diagnosis should:

  • Put the car in a dry parking, repair or other box. You can also use the garage. The main thing is that the humidity should not be too high;
  • Then you need to clean the cover of the distributor from dirt, after which the specified cover must be removed;
  • Then you need to rotate the engine crankshaft so that the distributor contacts are closed;
  • Now you can turn on the ignition and bring the high-voltage wire of the distributor to the “mass” by 3-7 mm;

After evaluating the spark, you can decide whether to change the ignition coil. Please note that repairing this item is often not practical. Also, when installing a new spare part, you must strictly adhere to the required polarity. If this is not done, then the new part will quickly become worthless after an unqualified installation. Note that in service stations, a special stand is used to check the coils. Such equipment allows you to check the coil taking into account various operating modes.

To check the spark on the spark plugs in the event that the distributor is working and there are no problems with the state of the high voltage wires, it is necessary to unscrew the spark plugs from the engine. In addition to contacts, you should look at carbon deposits, the degree of oiling of the electrodes, etc. For normal sparking, contamination must be cleaned. You should also check the gap between the electrodes, which is usually normally between 0.7 and 0.9 mm. If the gap is broken, then you can gently bend the side electrode. This method is a temporary measure, but allows in some cases to travel from several tens to hundreds of kilometers without “tripling” the engine in the event of a malfunction with the spark plugs.

If there is no spark: ignition module

The following symptoms indicate possible problems associated with the operation of the ignition module:

  • At idle, the engine troit;
  • Power decreases, the car accelerates poorly;

Engine friction is most pronounced in two nearby cylinders, and thrust drop is felt more strongly during attempts to sharply accelerate the vehicle, that is, with a strong and sharp pressure on the accelerator. On the dashboard of most cars in a similar situation, “check” usually lights up.

If the test of spark plugs and high-voltage wires did not reveal any problems, then the ignition module should be checked by a tester. The test consists in connecting one output of the tester to the module connector and feeding the other to ground. Then the motor can be started. A tester reading of 12 V indicates that the module is in order. Deviation in the readings of the device from the norm can indicate both the need to replace the module itself, and check / replace the corresponding fuses.

Useful Tips

Experienced motorists are well aware that spark plugs can fail at the most inopportune moment. For this reason, it is recommended that you bring a spare kit with you. The same can be said about the candle wires.

During work with the ignition system, extreme caution should be exercised, since it is possible to receive a strong electric shock. It is necessary to use insulated tools.

Since candles fail most often in comparison with other elements of the ignition system, the “spark” test always starts with them. Diagnostics can be done alternately. The procedure is carried out by unscrewing the candle from the cylinder head, then a cap and wire from the coil are put on the candle, after which grounding to ground is made. The main indicator during testing during rotation by the starter is the spark itself and its quality.

When removing the spark plug wires from the ignition module, it is advisable to mark each wire. This will allow verification and subsequent connection in a strictly defined order without the risk of confusing wires.

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How to check engine operation by spark plugs. The main signs of engine malfunctions: the appearance of black, gray, red and white soot on candles.

Signs of malfunction or breakdown of the high-voltage spark plug wire of the ignition system. How to check do-it-yourself car armored vehicles.

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Engine friction: symptoms. Why tripling occurs and how to find the reason why the motor starts to troit. Checking power, ignition, compression, etc.

What is indicated by the color of soot on the spark plug, why a soot of one color or another is formed. How to clean the spark plugs from soot with your own hands, tips.

How to check spark plugs with a tester

The serviceability of all components of the car guarantees its full performance. The slightest malfunctions can lead to the fact that the car simply does not start and does not drive. The most common are: fuel supply system, power supply system, cooling system, no spark on candles. Particular attention should be paid to the last failure, due to its frequency of occurrence. To check the malfunction, a spark plug tester is required.


Visually determine that problems with the supply of current in the car, it is almost impossible. For diagnostics, you should start the engine or drive the equipment at high-speed modes.

Before checking the ignition module, one should clearly know the symptoms of the “disease”. So, the first signals about problems with spark plugs:

  • The vehicle’s crankshaft rotates at the desired frequency, but the engine does not start. Due to the absence of a spark, there is no ignition of the combustible mixture;
  • In one or several cylinders, alternating flashes, fires occur, and as a result, the engine runs unstably, randomly;
  • The power unit works at the moment of rotation of the car starter. When the “trigger” stops rotating, the unit stalls;
  • A sharp loss in the power potential of the machine and, as a result, increased fuel consumption;
  • Catalyst failure due to a large amount of unburned fuel inside the segment;
  • Long process of starting the engine during medium and low temperatures on the street. At this time, an abundant amount of moisture is collected on the outer walls, which does not pass the spark of the candle;
  • All kinds of mechanical damage on the candle body, which leads to an unstable supply of current to the combustion chamber for ignition.

If there are pronounced deposits of black deposits on the body of the spark plugs, this indicates a malfunction in the power and fuel supply system. The cause of problems with the ignition cross-sections can also be the deterioration of the wires of the power system.

Diagnostic Methods

In many vehicles, access to the ignition system components is free and not cluttered with third-party parts. Therefore, the driver can easily check the candles at the initial stage for their performance. The main thing is to keep the sequence and not to confuse them when unscrewing from the cylinders. Checking the ignition module is always carried out with mandatory observance of order in relation to a group of cylinders. Mixing will lead to incorrect final conclusions.

How To Check Spark On Trimmer Candle

Initially, you should muffle the power unit, disconnect the wires from the conductors and the distributor themselves in turn. If the sound does not change during engine start, then the malfunction is on the face. Otherwise, continue your search further.

Spark test

The ignition tester is the easiest and most affordable way to quickly check the ignition system for performance. We twist each candle one by one, if necessary, wipe or clean it from soot. Using a special tester probe, we check the gaps between the electrode and the conductor body.

Tip. Each vehicle has its own standard for clearances, which can be found in the operating instructions. If there is no such book, consult a minder of the nearest service center or look for information on the Internet.

Next, we apply the conductor to the motor housing, most often it is the cylinder head cover. Thus, we provide constant contact in the power supply network. We start the starter for 3-5 seconds, look at the presence or absence of a spark. We also remember the color with which it skips, as it is important for further diagnosis. A blue color indicates the full performance of the conductor, red or another indicates a breakdown.

Multimeter check

A universal tester or multimeter helps you quickly check the performance of candles. Such a device is familiar to many car owners who have encountered repairing their vehicle. The main purpose of using a multimeter is to detect the presence or absence of a short circuit inside the candle.

The multimeter is very easy to use, its use does not require special experience or skills. For diagnostics, we unscrew the conductor, we alternately connect one terminal to the thread of the spark plug, the second to the central output. When voltage is applied, a spark should appear, which indicates the operability of the part, otherwise it must be replaced. Checking the spark plugs with a multimeter is the most common diagnostic option at home. If in the dialing mode the multimeter shows infinite resistance or very large, then the candle is considered non-working.

To check the resistance of the built-in candle resistor, the multimeter switch is set to 20 kOhm. One probe of the multimeter touch the central electrode, the other to the contact output. The resistance of all candles should be approximately the same with a small spread. In the spark plugs of injection engines, the resistance of the resistor is about 4 kOhm.

Check “gun”

In addition to checking with a multimeter and a special tester, there is also an original method called “checking with a gun.” Its essence is to investigate working capacity under pressure on a special stand. The algorithm is as follows: insert the conductor into the groove, put on the tip, after fixing, pull the trigger of the gun. The green indicator will indicate 100% performance, yellow. Insufficient conductivity, red. A malfunction of the spark plug. Despite the invention of such a device, it does not give 100% confidence in the diagnosis, since the pressure in the gun is slightly different from the pressure inside the cylinder.

Candle cleaning

Many novice car owners are faced with such a problem as cleaning candles. Rough handling can damage the product or damage it. When cleaning spark plugs with your own hands, use the following generally accepted methods:

As you can see, it takes very little time, effort and money to check the spark plugs. Enough 10 minutes, and your car will be in full combat readiness. Follow the recommendations of the article, check the color of the spark, then everything will be fine.

Spark test on spark plugs

We check the presence of sparks on the spark plugs of a carburetor engine with a contactless or contact ignition system. A stable strong spark between the electrodes of the spark plugs is the key to the normal operation of the engine in all modes from idle to power. Visually consider how spark plugs work and what kind of spark between their electrodes can be done by a simple test.

Before checking, make sure that the ignition of the car is turned off, and the battery terminals are stripped and have a reliable connection.

The procedure for checking sparks on spark plugs of a carburetor engine

  1. Turn out all the spark plugs.
  2. We connect high-voltage wires to them.
  3. We connect the threaded parts of the candles with wire.
  4. We connect the wire to the “mass”.
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The connection must be reliable with unpainted metal parts of the car body.

  1. The assistant cranks the engine with a starter.

When scrolling, observe the spark plugs. If an uninterrupted sparking is observed between the electrodes of the candles, the spark is strong. The ignition system, including the candles, is working. Otherwise (the spark plugs work once, the spark is weak), a faulty element in the ignition system should be identified. See “Checking the ignition system”.

Notes and Additions

Articles on the ignition system

How to check spark on spark plugs.Outboard engine ignition system

“The spark disappeared,” one can probably hear from every second person who, having tinkered with the boat motor for half an hour, was never able to start it.

On a hot sunny day, and even under pain of getting hit by a high-voltage current, it is not at all easy to consider whether a blue discharge light jumps between the electrode electrodes.

But back to the starting point: the outboard engine will not start. First of all, of course, check the power system, make sure that there is gasoline in the tank, not kerosene (and this happens), that the fuel supply hose is not transferred, that the float chamber is full.

Only having established that all this is in perfect order, let’s take a look to the ignition system. We begin the inspection with candles. Turn them out of the nests. Wet candles are a sign that fuel is entering the system but is not burning. Oiled candles must be replaced.

Check the spark. But first, a few words about the ignition systems that are used on outboard engines. High-voltage current is generated in induction ignition coils installed directly below the engine flywheel or brought out (the latter are usually called “reels”).

The principle of operation of these two systems is the same, but the system with remote coils works more reliably, gives a more stable spark. This can be explained by the fact that the bobbin is large (there is simply no place for a coil of such dimensions under the flywheel), therefore, it is possible to place a larger number of turns on it (and, therefore, increase the output voltage) with a larger insulation thickness between the rows of the winding (due to which reduces the possibility of closure. Breakdown).

So, check the spark. To do this, turn out the candles and close their bodies to the motor. We crank the motor by the starting cord, but with a force of about half that of a normal one. At the same time, a clear bright blue spark should slip through the candles. If the spark is pale, appears intermittently or only with sudden jerks, the ignition system is faulty and requires adjustment or repair. In such a case, it is desirable to have a set of ignition parts in stock (capacitor, chopper, reel), since it is very difficult to repair them, and sometimes it is simply impossible.

Inspection of the ignition system should begin with a high-voltage wire: check its connection to the spark plug, the insulation is working, then remove the starter disk that covers the flywheel window and check the condition of the breaker contacts. If they are oily, rinse them with a brush dipped in clean gasoline, clean with a file and set the gap on the dipstick. Along the way, it is necessary to check the conductors connecting the breaker, capacitor and coil. After that, check the spark again in the above manner.

If after such adjustment the spark is still weak, it means that a more serious check or even repair and replacement of some parts of the ignition system is required. It is necessary to remove the flywheel, wash the magneto with clean gasoline and carefully inspect. Remote bobbins should be interchanged. If the spark disappears on a working candle and appears on one that previously refused to work, then one of the bobbins is to blame and it must be replaced.

The most probable cause of magneto failure is the burning of the breaker contacts after prolonged use or due to poor operation of the capacitor; in order to eliminate this malfunction, it is necessary to remove the breaker, disassemble it and file the contacts with a file so that there are no traces of burning on them, give the contact surface a slightly convex (spherical) shape and polish these surfaces with fine sandpaper. Then clean the metal sawdust and emery dust of the hammer and the anvil and put them in place. If the quality of the capacitor is in doubt, then it is better to immediately replace it.

Some owners of engines, adjusting the ignition system, pay special attention to the fact that the contacts are absolutely flat and are located strictly parallel to each other. In my opinion, this is not true, and that is why. Such contacts will work reliably only when the probability of their contamination is excluded, which is impossible during operation of the outboard motor. A speck of dust that has fallen on any part of the contact surface may prevent it from closing. Even worse, if a drop of oil gets here, which can create an “oil gap”. A strong film that interferes with the normal operation of the contacts.

With the convex surfaces of the contacts I recommend, the plane of their contact decreases significantly, and a “point contact” is formed, which occurs at a much higher specific pressure. This pressure will “crush” almost any foreign particle trapped between the contacts. Sometimes I found that the convex contacts mounted on the magneto are very oily, only when I began to disassemble the motor. At the operation of the ignition system, the grease of such contacts was not at all reflected.

Magneto with high voltage coils under the flywheel often fail due to poor manufacturing of these coils. It is not always possible to determine whether they are serviceable, even in the laboratory, not to mention the traveling conditions. The state of the coil can only be judged indirectly. If there is no doubt the quality of the capacitor, chopper and high-voltage wire, but there is still no spark or it is very weak, then the whole thing is in the coil and it needs to be replaced.

When replacing the coil in Moscow or Veterka in traveling conditions, the primary conductor soldered to the core must be cut as close to the coil as possible. Then it will be more convenient to connect the wire of a new coil to the conductor.

The high voltage wire must be cut off from the removed coil and secured to a new one.

Another necessary condition for the smooth operation of the ignition system: all the screws of the magneto parts must be firmly tightened.

O. V. Gavrilov, “Boats and Yachts”, 1971

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