Checking The Ignition Coil Of A Chainsaw With A Multimeter

Methods for checking ignition coils

The ability to determine the cause of a breakdown of the ignition coil will always be useful and relevant for every car owner, because this unit is one of the most important in the design of an internal combustion engine. A minor malfunction in this part can cause unstable engine operation, and complete failure can cause engine failure.

Checking The Ignition Coil Of A Chainsaw With A Multimeter

Even taking into account the fact that ignition coils are quite reliable and rarely break down, they still fail, and the following reasons may serve as the most common reasons for this:

  • Overheating, overvoltage or vibration can damage the insulation, which in turn leads to a short circuit in the coil winding;
  • Defective spark plugs or damaged high voltage wires cause overloads in the coil, which can lead to winding breakage.

There are two ways to check the bobbin at home: by creating a spark between the spark plugs and the car body, or by using a coil tester (multimeter). At the first sign of unstable operation of a gasoline internal combustion engine, the first thing to do is check the ignition coil.

Despite the equal effectiveness of THESE two methods of checking the coil, the first one has recently been, and not only undesirable, but also dangerous for both a person and a car. The spark created can cause serious injury or, in the worst case scenario, kill a person. Also, this method can completely disable the ignition coil itself and all the electronics of the car (especially important for modern cars). Therefore, it is worth abandoning the “popular” method and resorting to checking the ignition coil with a tester.

Signs of a faulty ignition:

  • The chainsaw starts, but it works unevenly (troit), sneezes and shoots often;
  • The power of the chainsaw has dropped noticeably;
  • With a sharp press on the throttle trigger, dips in the engine are observed;
  • The chainsaw does not start well on a cold, strongly troit, Until it warms up;
  • Fuel consumption has increased significantly;

If such flaws appear in the work of your chainsaw, then it’s time to diagnose, adjust, and possibly repair the ignition system.

Chainsaw ignition

A chainsaw, like any device powered by an internal combustion engine, has an ignition system. It is responsible for igniting the fuel-air mixture in the engine cylinder. This is due to the supply of an electrical discharge, which breaks through the space between the spark plug electrodes.

It is clear that without fuel ignition, no engine will start and will NOT work. However, the problem is not only this: the quality of the chainsaw depends on how accurately the ignition is set. In other words, fuel ignites on time or at the wrong time. Therefore, a chainsaw with knocked down settings needs repair. The troubleshooting can be entrusted to an experienced mechanic, but you can repair the ignition of the chainsaw with your own hands.

Important: new chainsaws are supplied with adjusted ignition, there is a need to disassemble and assemble the tool immediately after purchase.

Some Chinese chainsaws come with substandard spark plugs. it may make sense to have several spark plugs included. In our review, we will introduce you to the device and how the ignition system works, its main problems and how to fix them.

Overview of fault detection using a multimeter

How to check the ignition coil of a chainsaw?

Often, the cause of a malfunction of the tool used is not only an incorrect gap between the existing standard flywheel and the standard coil, but the breakdown of the latter. In this case, you will need to carefully check the coil.

For this you need:

  • Inspect the condition of the coil body and make sure there are cracks and other defects on it;
  • Check the cleanliness of the coil elements and the electrical wiring connected to it;
  • Inspect the condition of the insulation of the wires;
  • Assess the reliability of the mountings;
  • Inspect the condition of the cap, which forms a spark;
  • Check the condition of the spark plug;
  • Check the performance of the spark plug switch;
  • Use a multimeter to check the voltage inside the unit.

To accurately determine the breakdown of the coil, you will need to use additional devices. an ammeter and a voltmeter. In this case, it is necessary to remove all foreign objects from the source of spark formation.

Check the coil in this order:

  • First you need to measure the resistance that the magneto creates. This method is used if the owner of the chainsaw knows the optimal parameters. When forming the required pulse, it will be necessary to separate the indicators formed by different semiconductor elements. In this case, a sign of a malfunction is the ringing of the circuit through the minus and high-voltage wire. As a result, the measuring device shows an overestimated resistance or an open circuit;
  • Next, you need to use the device, which will make it possible to check the operation of the candle and the presence of a spark. It will need to be connected at the point where the circuit is broken between the candles and the high-voltage wire. The disadvantage of this method is that the device required for testing is quite expensive.
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Another way to check the coil does not require the use of expensive instruments. It is only used in cases where the owner of the chainsaw no longer has options for diagnosing the ignition system. When checking from a candle, you will need to throw off the cap and insert a small nail into it. After that, the cap must be put on the candle in such a way that the distance between the nail and the cylinder is about 6-7 cm. After that, the dust must be brought in and inspected by the Spark. If the coil is intact, the spark will be bright blue. Other shades of spark will indicate a malfunction of the magneto.

Coil repairs should be done in a clean, dry place. In this case, it is necessary to exclude the ingress of dust, oil or other liquids on the parts of the mechanisms. Otherwise, there is a risk of short circuiting, which will lead to complex breakdown of the tool assembly.

Starter device

Often, manufacturers of chainsaws equip their units with starters that work on almost the same principle, namely: in the groove of the saw body there is a handle through which the cord is passed. When the handle is suddenly lifted, the cord is pulled out, which engages the drum of the ratchet mechanism. Thus, the spoked drum is driven, which is located on the shaft. At this time, the crankshaft makes several revolutions, leading to compression of the fuel mixture, which at this moment is located between the cylinder head and the piston. When the handle is lowered, on the contrary, the ratchet and spitz loses their contact, which leads to a stop of the shaft.

With an increase in the power of the chainsaw, the amount of the fuel mixture increases, which should ignite when the chainsaw is started. In this case, increase the number of pulls on the cord to start the engine. To speed up the return of the drum mechanism, manufacturers use a special steel starter return spring, which has excellent elasticity.

If the spring breaks, it is necessary to: remove the mechanism holder, pull out the spring, fixing its upper part with a finger and slightly pulling the starter handle to the side. Then, wind a new part, while avoiding bends and twisting of the new spring element, then carefully fix the clip.

Diagnosis of malfunction with a multimeter

Determine the malfunction of the ignition coil using the so-called hardware method. However, for this you must have a multimeter with which diagnostics are carried out.

Constructive components

All gasoline two-stroke engines have a similar operating principle, and therefore the ignition system in them has a typical structure and device.

Thorough check

If a preliminary assessment of the condition of the coil did not give results, you need to carry out a thorough diagnosis.

  • Experts recommend taking a multimeter and checking the resistance level of the coil. Study the optimal performance of your model (this information is in the instructions for the chainsaw). Please note that sometimes the “ringing” ends with an indication of “open circuit”, you should not panic, since many saws use semiconductor parts. A positive test result indicates a malfunction.
  • Checking the health of the electrical circuit. Lean the cable against the gap between the cylinder and the coil. In the absence of a breakdown spark, it can be concluded that the high-voltage cable is faulty, internal insulation is damaged.
  • Spark check (a special device is also used). The test device is placed between the coil lead and the candle bulb (this is called an open circuit). Pay attention to the data displayed on the screen of the measuring device, compare them with the optimal ones for your chainsaw. Not everyone can afford this test method at home, since special equipment is expensive.
  • Performing homemade ignition. This test assumes the use of a candlestick. It is taken out and leaned against the cylinder body, at the same time starting the starter. Watch the spark. The methods are not the most reliable due to the non-standard speed of rotation of the flywheel (since the position of the candle is unnatural), but many craftsmen actively use it.

In the field, when the above ignition check methods are not available, resort to this method.

  • For the method, you will need a carnation without a hat, which is placed close to the cylinder. 7 millimeters from it. Be careful not to damage the part.
  • Pull the starter and watch the spark. If it appears and is bright, there is a problem.
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The method is useful in the absence of electronic components. In addition, you will have to adhere to such rules.

  • DO NOT unscrew the plug completely to avoid speeding up the rotation of the flywheel. This will negatively affect engine performance.
  • The candle is placed so that the distance between it and the cylinder is not less than that recommended taking into account the dust compression model and the dielectric properties of the fuel mixture used (on average, it is placed at a distance of 7 millimeters).

How to check the ignition coil

One of the most important elements of the ignition system of any gasoline engine is the coil. It is she who is considered the main node of contact, contactless, as well as electronic ignition systems, acting as a kind of energy storage device intended for further distribution of the charge throughout the cylinder.

Methods for checking the ignition coil

Checking the ignition coil “Dedovsk” by the method can damage the electrician of a modern car

For proper self-checking of this car part, it is recommended to perform certain actions in stages. First of all, after removing the coil, you need to visually inspect it and make sure that there are no external signs of a short circuit: black dots, indicating burnout, cracks, or other signs of breakdown.

In our country, for a long time, there were two equally popular ways of how to check the ignition coil for operability: by checking the spark between the car body and the spark plug or by measuring the resistance of the windings with a multimeter (tester). The use of the first method can be fatal Not only for the coil, but also for the electronics of most modern cars, therefore, its use is strongly discouraged by manufacturers. It is safer to check this car unit with a measuring device.

Causes of coil malfunction

Partial damage to the ignition coil leads to unstable engine operation, and its complete breakdown makes it completely impossible to start the engine. That is why, when the engine is tripled, its power is lost or other signs of fuzzy operation, one of the first actions should be to check the ignition coil. This element fails quite rarely, and the malfunction, as a rule, consists in the following:

  • Insulation damage due to strong heat, vibration or high voltage, which in turn leads to a short circuit in the coil windings;
  • Overloading caused by defective high voltage wires or spark plugs can cause the coil winding to break.

Using a multimeter when checking a coil

In order to independently get a complete picture of the health of an element of the ignition system, you need to figure out how to check the ignition coil of a multimeter. This procedure does not have to cause special difficulties.

First, the primary winding is checked, to the positive and negative contacts of which the device is connected in the resistance measurement mode. Factory standard specifications may vary slightly from manufacturer to manufacturer, but average resistance values ​​should be between 0.4 and 2.0 ohms. If the device shows zero resistance, then a short circuit has occurred in the coil, if infinity, you need to look for an open circuit.

Checking the ignition coil with a tester

To check the secondary winding, a multimeter is connected to the positive terminal of the coil and the terminal from the high voltage wire. The resistance value of this winding in coils with a lamellar core is 6-8 kΩ, in the second types. the parameter can exceed 15 kΩ.

It is possible to draw a conclusion about whether the obtained indicators are within the limits established for a particular model, it is possible only Having an idea of ​​its other technical characteristics: duration and energy of the spark discharge, spark discharge current and the value of the inductance of the primary winding.

Any malfunction of the ignition coil has a negative effect on the efficiency of the car engine, and this can lead to a decrease in its durability. That is why its timely diagnosis and repair (or replacement) is necessary, if necessary.

Verification recommendations

Many novice motorists are interested in learning how to remove the ignition coil, because it is necessary to carry out the procedure with the dismantled device. It is worth knowing about the main types of problems that arise during the operation of this module.

Checking the ignition coil of a chainsaw with a multimeter

The ignition coil is one of the most important modules in gasoline power plants. If it turns out to be faulty, then the engine simply does not start. At the same time, computer diagnostics does not always allow you to accurately determine the presence of a malfunction, and in such a situation it is worth checking the ignition coil of the multimeter. Today this method continues to be very effective.

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Purpose and principle of operation

The ignition coil allows you to convert a low-voltage electrical pulse coming from a current source into a high-voltage pulse, without which it is impossible to get a spark. It can have from 1 to 3 petals in the breakdown gate. Depending on the technical characteristics of the power plant, the breakdown gap can be in the range of 0.4-1.1 mm.

To ensure reliable ignition, the voltage of the electrical impulse must be at least 10 kV. In this case, one should remember about a possible voltage drop in the conductor and therefore the coil must generate a pulse of 12-20 kV.

Such stress can pose a serious danger to people, and this is especially true for those who suffer from various heart ailments. When checking a defective coil, you need to be very careful, because even standard rubber gloves cannot guarantee complete safety.

The principle of operation of this element resembles an autotransformer. To create the primary winding, a copper wire coated with insulating varnish is used. Most often, the number of turns is 100-200. The secondary winding consists of a thinner conductor, but has 2000-3000 turns.

During operation of the power plant, the cam mechanism rotates, located in the distributor. The main task of this element is to open contacts. When a short opening occurs, a high current flows through the primary winding. This leads to the appearance of induction in the secondary winding, and a high-voltage pulse is transmitted to the spark plug gap.

Today the situation has changed and manufacturers are actively using more reliable devices instead of breakers, for example, a Hall sensor. If the user needs to know how to check the ignition coil of a chainsaw with a multimeter, then this procedure is carried out in the same way as for testing car spark plugs.

Major malfunctions

It is quite easy to find the device in old cars, because it was installed in the field of visibility of the motorist. If you start searching from the center conductor of the ignition distributor, then there will be no problems. You can also quickly find individual coils, most often located above the candles.

Among the main signs of malfunction of this module should be noted:

  • There is no spark and the engine cannot start.
  • The power plant troit during operation and this is especially noticeable at high humidity.
  • During computer diagnostics, misfire was detected in some cylinders.
  • There is a drop in traction when you press the accelerator pedal.
  • The power plant hardly starts up “idle” and, first of all, at low air temperatures.
  • Serious overheating of the device is observed.
  • Leads matching the device have changed color.

Often, vehicle owners are partly to blame for problems with this element. Wanting to save money, many decide to use non-standard spare parts. If we talk about the most common malfunctions, then we can note:

  • Reverse battery polarity.
  • Frequent overheating of the coil.
  • Short circuit electrical wiring.
  • Mechanical damage to the device.
  • Sharp temperature fluctuations.


It is also necessary to familiarize yourself with the information on how to ring the ignition coil with a multimeter, because this information will be useful to all owners of devices equipped with gasoline power plants. This measuring device allows you to monitor voltage and resistance. The switch of the measuring device must be set to the “200 Ohm” position and, applying the probes to the contacts “” and “TO”, measure the resistance value of the first coil winding.

Most often, difficulties arise when diagnosing double coils, since the primary winding in them is the connections with the connector. To check it, you can use a multimeter only if the user is familiar with the coil circuit. Diagnostics of the secondary winding is carried out between two high-voltage conductors.

Without a certain set of knowledge in the field of radio electronics, it will be quite difficult to determine the malfunction of individual coils, since it is necessary to assemble an electrical circuit. However, there is one way that always works. If the power plant is troit, then you should start sequentially disconnecting the coil terminals while the engine is running.

If after that the motor began to double, then there is no spark in this cylinder. To solve this problem, it is possible to carry out computer diagnostics. But even if during the check the cylinder number without a spark is indicated, this does not allow us to unequivocally speak of a coil malfunction. Knowing how to check the resistance of the ignition coil with a multimeter, you can quickly determine the source of the problem and replace the failed element. Many motorists change branded coils on foreign cars for devices from VAZ, since they are much cheaper.

Originally posted 2018-07-04 8:07:29.