How to Test the Stihl Chainsaw Ignition Coil

The chainsaw ignition system is a series of parts that form a spark when starting the tool engine. In most cases, the ignition system is a fairly reliable unit, but sometimes, for various reasons, some of its parts fail. Let’s study the features of repair and adjustment of the main elements of the chainsaw ignition system.

The device and principle of operation of the ignition system of a chainsaw

The ignition system of modern chainsaws consists of a list of important details. The main structural elements are:

  • Spark plug;
  • Flywheel magneto;
  • Wiring;
  • Power button.

The ignition system also includes an ignition coil, chopper and capacitor. The coil is responsible for turning on the core and the winding of the transformer. Candles in the design of the nodes consist of a side and central electrodes, an external housing and an insulator.

The circuit breaker and coil winding in the design are connected in series. The breaker is switched off due to the presence of a cam on the crankshaft of the chainsaw. The ignition system magneto is located to the left of the crankcase and is secured with a nut and two studs.

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How to Test the Stihl Chainsaw Ignition Coil

In the process of starting the chainsaw with the help of flywheel magnets, a magnetic field is formed that crosses the coil. Provided that the contacts of the primary winding are in a closed state, a weak current is generated in the ignition system. If the contacts are in the open state, then the magnetic field is not formed, which leads to the appearance of high voltage in the secondary winding. Subsequently, the current is supplied to the candle, which sets fire to the fuel to start the chainsaw.

How to set the ignition on a chainsaw?

Quite often, chainsaw owners are faced with a problem in which the tool engine does not start. One of the main reasons for this failure is the malfunction of the ignition system, namely, a failure of the factory settings of the unit.

Видео: How to Test the Stihl Chainsaw Ignition Coil


First of all, the owner of the saw will need to unscrew the protective rubber cap and check the candle under it. It is possible that it is flooded with oil, which prevents the current from entering the candle. In such cases, the problem lies not in the ignition system, but in the fuel system, namely, in the depressurization of the channels.

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However, if the candle is completely dry, it means that you may need to install the ignition on a chainsaw. To do this, unscrew the candle and dismantle the protective cover. After this, the clearance between the flywheel and the ignition coil must be measured. The instructions for each of the chainsaw models indicate the optimal clearance between these elements. In most cases, it is from 0.2 to 0.4 mm. Since the flywheel of the tool has a round shape, it will not be possible to use a car probe to adjust the clearance. It is best to use a special template in the form of a gasket for this purpose. However, finding it is not so simple. Therefore, many experts advise using a cut strip from a plastic bottle as a template.

Adjusting the ignition of the chainsaw is quite simple;

  1. To begin, loosen the bolts securing the ignition system;
  2. Install the plate from the plastic bottle between the coil and the flywheel;
  3. Tighten the bolts to the end.

How to check the ignition coil of a chainsaw with a multimeter?

Accurately determine the breakdown of the ignition system of the chainsaw will help a special device. a multimeter. It will make it possible to determine if there are breakdowns of the coil and other elements of the assembly. The procedure is as follows:

  1. First you need to set the multimeter so that the arrow of the device is located at around 200 ohms;
  2. After that, you need to open the operating manual of the chainsaw and study the optimum resistance indicated there for the primary winding of the ignition coil. As a rule, this indicator ranges from 3 to 5 ohms;
  3. Next, you need to connect the primary ignition coil to the device. If the performance of this part of the coil is normal, we begin to check its secondary winding;
  4. We study the operating instructions again and look at the optimum resistance values ​​indicated for the secondary winding. It is worth noting that this part of the element has great indicators, so the multimeter should be set so that its arrow is located next to the 20K indicator;
  5. Next, we connect the device to the hole of the coil into which the wires are inserted. If the multimeter shows normal values, then the coil is fully operational. However, if the resistance on the display of the device is far from the parameters specified by the manufacturer, then the coil will have to be changed.