How To Install The Ignition On A Lawn Mower

Chainsaw ignition Chainsaw ignition system. This is a whole complex of elements with the help of which a spark appears when starting the engine. It is needed in order to ignite the fuel

Chainsaw ignition scheme Ural

The device of the ignition system of modern chainsaws

Magneto Stihl MS 180

Ignition systems used to be rather unreliable, but now they have improved. So, in their control system there are elements that regulate the momentum depending on what the saw speed is. This allows the motor to run more efficiently, which increases the overall efficiency of the tool. In addition, such elements are important because they make it easier to start the saw initially.

An equally important fact is the reliability of modern systems. If earlier the ignition failed very often, now all its components are so strong and of high quality that they rarely need to be repaired.

So, the modern chainsaw ignition system is a flywheel magneto, a spark plug, a wire and an ignition off button. Distinguish between contact and non-contact magneto. The device of the first is quite simple: permanent magnets (installed in the rim of the flywheel), an ignition coil, a capacitor and a breaker. The coil, in turn, includes a core, as well as the primary and secondary windings of the transformer. Another important element is the spark plug. Its design is as follows: central and side electrodes, insulator, outer casing.

The breaker and the primary winding of the coil are connected in series. The breaker is turned off due to the presence of a cam on the crankshaft. The primary winding is connected in series not only with the breaker, but also with the off button. Magneto is mounted in the crankcase on the left, secured by the base on two studs and nuts.

The flywheel magnets generate a magnetic field that crosses the coil. Due to this, if the contacts in the primary winding are closed, a weak current is generated. Accordingly, when the contacts are open, there is no magnetic field and an EMF is induced in the secondary winding. This generates a high voltage current, which is supplied to the spark plug and gives a spark to ignite the fuel. At this moment, the piston is almost at the top dead center (4 mm below it).

Chainsaw ignition module (coil) problems

Husqvarna chainsaw ignition coil

The switch and the ignition module that regulates its operation can often fail. The coil may also be faulty. If all elements of the ignition system are in good working order, but there is no spark, suspect the module and the coil. And the problem of a malfunction of these elements is that it is impossible to repair the module or fix part of the coil, they need to be replaced. Of course, if possible, it is better to put the module from some old saw and see if this is the case. After all, you can simply make a mistake at some stage and suspect what actually works.

Do not trust all kinds of testers, they often show false information about the health of the ignition system. Only diagnostics with a different module or coil will be valid.

If the electronic module is bad, there is such a symptom: as soon as the chainsaw heats up, a very weak spark is emitted. Also, after refueling, the unit may not start. This is due to the fact that the coil or module is very hot, their resistance increases, so the spark weakens.

If there are breakdowns in the ignition system, and there is no experience in repairing them, you should not try to repair everything yourself. Elementary things, such as checking the integrity of a candle or wires, can be carried out at home, but more complex diagnostics, and even more so, the replacement of units should be carried out by professionals. And then you can be sure of the quality of the work performed.

Read more:  Lawn Mowers: Gasoline Self-Propelled Viking Lawn Mowers


The main problem in this group is the engine.

Ignition is one of the main elements affecting the trouble-free operation of the tool. Therefore, we will first consider this particular block.

Gone are the days when the switch with cams and a moving contact, which supplied a spark to the spark plug, was engaged in ignition control.

It was not a very reliable system due to the many elements that affected the operation of the engine. The chainsaw, with no visible malfunctions, could simply stop starting. And we could observe a picture of constant tugging at the winding cord. Today, manufacturers have switched to non-contact ignition systems.

They have fewer moving parts and there are no contacts that need to be exposed periodically, often failing. The reel used on a modern chainsaw will work until the end of the service life of your tool. The chainsaw has become much more reliable and easier to maintain.

how to install the ignition on a lawn mower

Constructive components

All engines, whether automobile or other tools using an internal combustion engine, have similar operating principles.

Not an exception, there are such eminent chainsaws and are used with pleasure by consumers like Goodluck, Stihl or Husqvarna.

The drive in them is the familiar internal combustion engine, respectively, a fuel tank, an engine and a working body that directly performs work, as well as other attachments that help in control.

Sometimes during operation some problems may arise, in this rather reliable tool like a chainsaw.

The question arises, what to do then?

Here are some common cases:

  1. The chainsaw won’t start;
  2. If it starts, it works intermittently;
  3. Insufficient power for proper operation.

Possible malfunctions

If the saw does not start, the first thing to check is the spark plug that ignites the fuel in the cylinder. Start by removing the high voltage wire that the candle is connected to. Then unscrew the candle itself from the cylinder cover and inspect its condition. When working properly, the candle should be dry and small deposits on the light-colored ceramics:

  • If the plug is wet, there is a problem with the carburetor. It is necessary to adjust and set the fuel level in it;
  • Carbon deposits on the walls of the plug of a dark or black color means malfunctions in the piston group.

If you did not find any visible reasons for the malfunction here, the candle is dry, light carbon deposits continue to go from the opposite direction. Since this is the final point of ignition of the working mixture. Now check if the spark is coming to the spark plug. This is the ignition system block.

Checking if there is a spark will not pose any particular problems, for this it is enough to take the high-voltage cable to which the candle is connected, bring it to the cylinder block, setting a small gap between them, so that you can notice the spark slipping between them. Then we pull the starter starter cord, and watch, there is a spark and what color it is. A working spark plug should produce a spark similar to lightning. How it looks, look at the photo offered to your attention, everything is clearly visible on it.

Now let’s try to set the correct gap between the movable and fixed contact. Ideally, it should be 0.2 mm. You can check with a probe, since it is not a deficit.

This was a description of the malfunctions of the older generation of chainsaws. The new generation includes modern chainsaws from Goodluck, Stihl and Husqvarna.

Constructive components

All engines, whether automobile or other tools using an internal combustion engine, have similar operating principles.

Not an exception, there are such eminent chainsaws and are used with pleasure by consumers like Goodluck, Stihl or Husqvarna.

The drive in them is the familiar internal combustion engine, respectively, a fuel tank, an engine and a working body that directly performs work, as well as other attachments that help in control.

Sometimes during operation some problems may arise, in this rather reliable tool like a chainsaw.

Read more:  Mower For Tiller.

How to set the ignition on a chainsaw

In this review presented to your attention, we will try to reveal the question that arises among many owners of chainsaws. In the process of using such a tool, the consumer may be faced with a situation in which it is necessary to correct the ignition timing. Over time, the breaker may fail, the coil also does not last forever, although it serves much more and it is quite difficult to disable it. So let’s figure out how to set the ignition on a chainsaw.

Basic malfunctions and their elimination

If you cannot start the saw the first time, there may be several reasons. The most common problem is with the spark plug:

  • Electrode wear or damage to the ceramic insulator;
  • Loose fitting of the removable cap (if any);
  • Sparks running along the ceramic winding, a sign of which is a brown residue on the outer shell;
  • Cracks in the cap of the candle (a saw with this problem will continue to work, but it may hurt the user when touched).

If no problem was found with the spark plug, it is recommended to inspect the wires coming from the coil. They can be cut off or have other mechanical damage. There may be wire breaks inside the insulation, so sometimes these violations cannot be detected by visual inspection.

The cause of the breakdown may lie in the shutdown switches. It is not difficult to check them. To do this, disconnect the wires from the module, and then check the ignition. If a spark appears after shutdown, the switch must be replaced.

Check the ignition coil on the chainsaw

If the preliminary actions did not help in identifying the cause of the chainsaw malfunctions, then it is necessary to check the saw ignition coil. Diagnostics is performed in several stages:

  1. Measure the resistance of the coil using a multimeter. To do this, you should know the optimal parameters, which are indicated in the operating instructions. However, due to the use of semiconductor elements in the system, an attempt to “ring” the coil will result in an open circuit reading. This is normal. A positive test result is a sign of a malfunction. That is, if it was possible to determine the resistance of the coil using a special tool, then it is definitely faulty.
  2. Check for spark with a special device. This device should be installed in the open circuit located between the spark plug and the high voltage terminal of the saw ignition coil. The readings will be visible on the display. This method of verification is more commonly used in service centers, since the device required for this is expensive and the costs will not be comparable to the benefits rendered.
  3. Testing the coil with a spark plug, i.E. Making a homemade ignition. To do this, it must be turned out, and then the body must be attached to the cylinder. Now you need to pull the starter and observe the spark. But this method gives only an approximate result, since the flywheel turns faster due to the unnatural position of the candle.

If none of these methods work, or if you need to perform a check in the field, you can proceed as follows:

  1. Remove the cap from the candle, insert a nail without a cap into the core at a distance of 6-7 mm from the cylinder. This must be done as carefully as possible so as not to damage the part.
  2. Carry out the steps to be taken when the tool is manufactured. Now you need to look at the presence of a spark and its color. If there is no fault, then the spark will be strong and the color will be bright blue.

This method can be used as a last resort and only if there are no electronic components, while it is important to follow the rules:

  • You cannot completely unscrew the spark plug, as this can lead to faster rotation of the flywheel, which is not the correct mode of engine operation;
  • You need to place it at a distance that corresponds to the compression model and the dielectric properties of the fuel mixture, therefore this parameter can be viewed in the instructions (the value of 6-7 mm is average).
Read more:  Viking Oil Mower Change Frequency

How does the ignition of a chainsaw work and how does it work?

The carburetor engine design does not depend on the tool model. Therefore, we can talk about a standard chainsaw ignition system. It consists of the following elements:

  1. Magneto. It is an alternating current generator. Required to supply the spark plug with electrical current. Outwardly, this part looks like a stationary winding of an inductor and a permanent magnet, which is fixed on the flywheel. The latter rotates simultaneously with the engine crankshaft.
  2. Spark plug.
  3. An electrical cable that connects the 2 previous elements.
  4. Device shutdown buttons.

The chainsaw ignition scheme is simple. After starting the tool, a rotating magnetic field is generated due to the movement of the flywheel and crankshaft. It creates a moving force in the existing winding, which is transformed into voltage. This potential is enough for the formation of a spark.

Differences in different models of chainsaws may only be whether a contact or non-contact magneto is used. In the first case, one terminal of the winding goes to the candle, and the second first to the shutdown button, and then through it to the ground. In the second case, the device has a capacitor, which, when discharged, forms a current.

Trimmer ignition setting

Gasoline trimmers use both two-stroke internal combustion engines (ICEs) and four-stroke ones. But the ignition system in them is no different from each other, therefore, the repair and adjustment of this fuel ignition system will be the same for different types of internal combustion engines.

Why do I need ignition adjustment

In some cases, when the engine does not start, ignition adjustment will be required. Of course, first you need to check the condition of the plug and the high-voltage cable with a cap.

It is necessary to adjust the ignition on a two-stroke engine in order to ensure timely ignition of the fuel in the engine combustion chamber. Below is a diagram from which you can understand the principle of operation of the internal combustion engine.

The spark in the plug should appear at the moment the fuel is compressed by the piston, when it does not even reach the top dead center (TDC). When the piston passes TDC, the fuel mixture ignites, as a result of which the piston goes down under the action of the explosion energy.

Therefore, if for some reason (mainly due to the displacement of the flywheel on the shaft relative to its initial position), the fuel ignites before the piston passes TDC, then it goes back, and the crankshaft rotates in the opposite direction. This movement can damage the starter assembly, cut the starter cord, etc. In this case, early ignition of the fuel occurs.

There may also be a late ignition on the trim: the piston, after the compression of the fuel that has not ignited, goes down, and at this moment a spark appears. In this case, the engine will either not start, or it will significantly lose power and it will be difficult to gain speed.

But such problems with early or late ignition on two-stroke internal combustion engines are quite rare, since the flywheel with magnets is already installed in the correct position, which is perfectly synchronized with the movement of the piston. In addition, the flywheel is secured to the shaft with a key and nut. Therefore, incorrect installation of the part is excluded.

How the trimmer ignition system works

The ignition system of a two-stroke internal combustion engine consists of 2 elements: a flywheel and a coil (magneto). The figure below shows how they look.

The flywheel has an impeller that acts as a fan to cool the engine. Also on one side of the flywheel are permanent magnets, shown by an arrow in the figure.

When the flywheel rotates, an electric current is generated in the coil, which serves to produce a spark on the spark plug. A spark appears when the magnets are directly below the magneto.