How to adjust the ignition on a lawn mower

Ignition adjustment procedure

Setting up the ignition system is simple and identical on different trimmer models, be it a Stihl FS55, AL-KO BC 4125 or another lawn mower. First you need to remove the casing from the engine, having previously unscrewed the fasteners that fix it. This disassembly step may differ from model to lawnmower (described below). Next, you need to partially unscrew the fasteners that fix the magneto with a screwdriver, and turn the flywheel so that the magnets are in the upper part.

adjust, ignition, lawn, mower

In order to create an optimal gap between the coil and the magneto, a special template must be used. It is impractical to buy it for a single use, therefore, as an alternative, you can use a business card or a small calendar, as well as an A4 paper sheet folded in four. A strip cut from a plastic bottle or other available materials that have the required thickness is also suitable. The optimal distance is usually indicated in the user manual. The selected item must be placed between the magnets and the coil.

The coil will then be attracted to the flywheel by the magnetic field. While holding the magneto in this position, you need to tighten the fasteners that fix it, and then pull out the business card. After that, you need to turn the flywheel several times to make sure that it does not touch the coil at all. The process is over. the lawnmower’s ignition is on. You can learn more about the process of adjusting the trimmer ignition system on the Internet, where many videos on this topic are available.

When adjustment is needed

It is necessary to adjust the ignition system so that the fuel ignites in the combustion chamber at the right time.

Important! When the piston compresses the fuel and almost reaches dead center at the top, a spark is generated in the spark plug. Further, when it passes the maximum high point, the fuel ignites, as a result of the explosion, energy is generated and directs the piston down.

If the flywheel is displaced on the shaft from its original position, the fuel ignites faster than the piston crosses top dead center. As a result, the piston moves backward and the crankshaft rotates in the opposite direction. An early ignition of fuel can be determined by a broken starter cord, a broken starter assembly or other breakdowns.

Sometimes ignition is late. The piston compresses the unignited fuel, and then goes down, and only then a spark is formed. As a result, the engine either does not work, or its power decreases, and the speed is gained much more slowly.

Usually, the flywheel with magnets is set in an ideal position, precisely coordinated with the operation of the piston, and is carefully locked to avoid misalignment. This allows us to assert that the incorrect installation of the part is impossible. But if the flywheel offset is a confirmed fact, then it is a malfunction or an accident. Thus, setting the ignition timing is not required, since problems with early or late ignition of the fuel are very rare.

Important! It is very easy to adjust the ignition system. There is no need to calculate the ignition timing. The most that needs to be done is to correctly set the clearance between the flywheel and the coil.

Second way

If you cannot use the tester, there is another way to test. In this case, it is important not to touch the cylinder with the electrode, otherwise the coil will be damaged.

  • Remove the spark plug cap. You should not unscrew the plug, as this will preserve the compression.
  • Then you need to pick up the nail with the removed cap and insert it tightly into the cap.
  • Next, the cap with the nail should be securely tied to the cylinder with a dielectric. In this case, the electrode should be at a distance of 5.5-7 mm from the cylinder body, but not touch the mass.
  • Then, using the starter, you need to simulate starting the engine with the ignition button turned on. In this case, you need to carefully monitor whether a spark appears, and try to determine its color.

Important! A strong spark of white or blue tinge indicates that the magneto is in good working order. If it is weak, or orange or yellow, the magneto is damaged.

There is one important point to consider when diagnosing: unheated magneto in any state can form a powerful spark. However, if it is faulty, then, after warming up, it stops generating current, and the trimmer will not start. Later, after cooling down, the coil returns to the operating level again, the tiller turns on and runs for some time at idle or under load, until the temperature of the magneto rises again. In this case, the part must be replaced with a new one.

On a note! In a number of situations, the problem with heating is not due to the fault of the coil, but due to the spark plug. This means that both parts must be checked.

Typical malfunctions

Before you start adjusting the ignition of the trimmer, you need to cut off other probable causes of breakdown and make sure that the problem is really in this unit. To do this, it is necessary to carry out a number of actions in the following sequence:

  • inspect the ignition coil housing for damage and defects;
  • make sure that there is no contamination on all nodes and elements that conduct current;
  • check the integrity and insulation of the wiring, contacts, fastening strength, the presence of rust at the joints;
  • inspect the candle cap, as it regularly comes off the high-voltage wire, and they try to restore it manually, and any unreliable connection reduces the power of the electric arc of the candle;
  • check the candle, since the quality of modern gasoline very quickly destroys this part, but there is another possible problem. the candle is wet;
  • make sure the circuit breaker is working.
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Having excluded all possible malfunctions, you can proceed to adjusting the ignition of the coil.

How to set the ignition on the trimmer

Often, owners of gasoline braids are faced with the fact that the ignition does not work on their equipment. In most cases, the problem is really with this node. To fix it, you need to adjust the ignition on the trimmer. But at the same time, it is not uncommon for the ignition coil to be in good working order, and the breakdown must be looked for elsewhere. The ignition system is designed in the same way on four-stroke and two-stroke internal combustion engines, therefore, troubleshooting of this unit is performed in a similar way. In addition, the technique of different brands has almost the same design of this most important component of the tool, which means that the adjustment process will be identical both for the Soyuz or Prorab trimmers, and for Huter or samples of other brands.

Trimmer ignition. principle of operation and possible malfunctions

If the owner of the lawn mower wants to adjust the ignition system on his own, he should understand the principle of operation of this unit. In an internal combustion engine, it consists of a flywheel and a magneto (coil). In turn, the flywheel includes an impeller that performs the function of cooling the motor and a number of permanent magnets.

Operating principle

As the flywheel spins, an electric current is generated in the magneto, creating a spark on the spark plug as the magnets pass under the coil.

Magneto diagnostics

Magneto is a key component in engine ignition systems. It is a core coil that is surrounded by a primary and then a secondary winding. If this part is defective, there is no spark on the spark plug and the fuel will not ignite.

How to adjust the ignition correctly: step by step instructions

Many novice owners of cars, motorcycles, trailers and other vehicles with internal combustion engines may have problems with the ignition system. Let’s take a look at how to properly adjust the ignition on cars, motorcycles and other equipment.

Adjust the ignition

The first step is to unscrew the spark plug on the first cylinder. After that, the hole must be closed with a rubber stopper. Next, using a special key, it is necessary to turn the crankshaft until the first cylinder switches to the compression stroke. This is easy to understand. the piston will begin to move upward. You can see this by the traffic jam. it will gradually squeeze out. Rotate the shaft until the mark on the pulley is completely aligned with the mark on the timing case cover. For 95th gasoline, the middle mark is suitable.

Now release the latches and remove the distributor cover. After you have rotated the crankshaft, the rotor of this mechanism should turn so that the outer contact turns towards the first cylinder on the distributor cover. After aligning the marks, look at the distributor and run the line through the latches. the correct imaginary line will be parallel to the engine axis. If your line is not parallel, then there is more information for you on how to adjust the ignition.

Unscrew the nut that secures the distributor and turn it up. Rotate the rotor and align it parallel to the motor axis. Install the distributor, tighten the nut, but not tightly. Then you can proceed to setting the moment.

Lead angle moment

This is one of the most important parameters. It determines the correct operation of the entire system.

It takes time for the mixture to burn effectively. The speed at which the flame spreads is 20 m / s. If ignition occurs at top dead center, then the fuel will burn at the expansion stroke and partially at the outlet. As a result, the pressure on the piston will not be sufficient. You need to choose the right moment. then the pressure from the expansion and combustion of gases will fall on the TDC.

Ignition systems on gasoline internal combustion engines: device

Without this system, the operation of any engine is simply impossible. It is responsible for igniting the fuel mixture in the combustion chambers at a specific time. There are several types of such systems. First. this is a contact, in which impulses are created at the break of contacts.

For two-stroke units, which are most often found on tillers, mopeds and scooters, magneto is used as a device to create a spark. The EMF principle works here. A permanent magnet rotates in a coil, and this is how an impulse is generated.

Any of the systems includes several basic elements. So, a battery is used as a power source, and if the engine is running, then a generator. The switch is a mechanical lock. It often serves several functions. Energy storage is either a coil or a capacitive storage. Candles are also used in the system. They have two electrodes at a short distance from each other. The candle is a porcelain insulator that is threaded. In the central part there is a conductor-electrode, and a thread is used as the second electrode. How to adjust the ignition? It is not difficult.

How contact ignition works

This equipment allows you to get a spark of a sufficiently high voltage at the contacts of the spark plugs. The voltage for the automotive system can be up to 30,000 V. In order for the spark to be generated, the contact of the spark plug is connected to the coil.

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Best way to set the gap on any ignition coil, magneto, armature, part 1

For the engine to work efficiently, it is necessary that the moment of spark formation fully corresponds to the position of the piston group in the combustion chambers. To achieve this, a well-designed mechanism is used. distributor transmitting rotational energy to the breaker.

Among the disadvantages of such a system, there is a high impact of mechanical wear on the formation process and the quality of the spark. It also significantly affects the quality of the internal combustion engine and requires adjustment. Therefore, it is so important to know how to adjust the ignition.

Electronic system

Here the mixture ignites without any mechanical devices or any moving parts. With the help of special sensors and control units, a spark is generated exactly at the right moment. With this equipment, the operation of the internal combustion engine is significantly improved, its power increases, and fuel consumption is reduced. over, electronic ignition is very reliable and requires virtually no adjustment.

Contactless ignition

This group of car electrical equipment does not depend on the distributor. The main device in the process of spark formation is considered to be a transistor switch, as well as a special sensor. In this system, there are no dependencies between the quality of sparks and the cleanliness of the surface of the contact groups. this is a guarantee that the spark will be of very high quality, regardless of various factors.

The main problems and malfunctions of the carburetor.

Mesh filter. With this element, there are often only two obstacles:

In order to find out the cause of the breakdown, the fuel filter cap is unscrewed to remove the strainer. If dirt just accumulated on it, then flushing in gasoline or purging will help.

If there is visible damage to the mesh filter, it is imperative to install a new one. There may also be damage to the fuel supply pipe (during repair, they practice checking this element).

How to set timing on a lawnmower.

The carburetor starter in most cases does not work due to blockages. Use acetone or the same gasoline for flushing.

Blowing out parts of a carburetor with a blockage with compressed air is an acceptable and comfortable repair practice.

The body of the throttle valves, the places of the bundles of the carburetor parts, the inlet or outlet pipeline. all of these parts are subject to depressurization. You can probably check it with a simple method. smear the problem area with soapy foam.

The first way

You can check the performance of the magneto using a tester. To do this, you need to perform the following sequence of actions.

  • Correctly configure the tester: use the resistance measurement function and set 200 Ohms to take measurements of the primary winding.
  • Direct the first electrode of the measuring device to the “mass” of the magneto, and the second to the output contact. If the primary winding is in good condition, the indicators should be from 0.4 to 2 ohms.
  • Set the tester switch to 20KΩ to diagnose the secondary winding. Then direct the first probe to the candle cap, and the second to ground. If everything is in order, the figures will vary from 4 to 6 Kom, depending on the trimmer model, whether it is a Patriot 547, a Husquarna 128 r or another brand of equipment. If the circuit is open, the tester will display an infinity value. And if there was a short circuit, the display will show zero.

Typical malfunctions

Before you start adjusting the ignition of the trimmer, you need to cut off other probable causes of breakdown and make sure that the problem is really in this unit. To do this, it is necessary to carry out a number of actions in the following sequence:

  • inspect the ignition coil housing for damage and defects;
  • make sure that there is no contamination on all nodes and elements that conduct current;
  • check the integrity and insulation of the wiring, contacts, fastening strength, the presence of rust at the joints;
  • inspect the candle cap, as it regularly comes off the high-voltage wire, and they try to restore it manually, and any unreliable connection reduces the power of the electric arc of the candle;
  • check the candle, since the quality of modern gasoline very quickly destroys this part, but there is another possible problem. the candle is wet;
  • make sure the circuit breaker is working.

Having excluded all possible malfunctions, you can proceed to adjusting the ignition of the coil.

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 candle 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 spark 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 could damage the starter assembly, cut the starter cord, etc. In this case, early ignition of the fuel occurs.

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There may also be a late ignition on the trim: the piston, after 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 bad to gain speed.

Basically, ignition adjustment is about setting the correct gap between the magneto and the flywheel.

When adjustment is needed

It is necessary to adjust the ignition system so that the fuel ignites in the combustion chamber at the right time.

Important! When the piston compresses the fuel and almost reaches dead center at the top, a spark is generated in the spark plug. Further, when it passes the maximum high point, the fuel ignites, as a result of the explosion, energy is generated and directs the piston down.

If the flywheel is displaced on the shaft from its original position, the fuel ignites faster than the piston crosses top dead center. As a result, the piston moves backward and the crankshaft rotates in the opposite direction. An early ignition of fuel can be determined by a broken starter cord, a broken starter assembly or other breakdowns.

Sometimes ignition is late. The piston compresses the unignited fuel, and then goes down, and only then a spark is formed. As a result, the engine either does not work, or its power decreases, and the speed is gained much more slowly.

Usually, the flywheel with magnets is set in an ideal position, precisely coordinated with the operation of the piston, and is carefully locked to avoid misalignment. This allows us to assert that the incorrect installation of the part is impossible. But if the flywheel offset is a confirmed fact, then it is a malfunction or an accident. Thus, setting the ignition timing is not required, since problems with early or late ignition of the fuel are very rare.

Important! It is very easy to adjust the ignition system. There is no need to calculate the ignition timing. The most that needs to be done is to correctly set the clearance between the flywheel and the coil.

Trimmer ignition. principle of operation and possible malfunctions

If the owner of the lawn mower wants to adjust the ignition system on his own, he should understand the principle of operation of this unit. In an internal combustion engine, it consists of a flywheel and a magneto (coil). In turn, the flywheel includes an impeller that performs the function of cooling the motor and a number of permanent magnets.

How to Set/Adjust the Air Gap on Small Engines Armature Magneto Coil

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 picture below shows how they look.

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

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.

Ignition adjustment procedure

Setting up the ignition system is simple and identical on different trimmer models, be it a Stihl FS55, AL-KO BC 4125 or another lawn mower. First you need to remove the casing from the engine, having previously unscrewed the fasteners that fix it. This disassembly step may differ from model to lawnmower (described below). Next, you need to partially unscrew the fasteners that fix the magneto with a screwdriver, and turn the flywheel so that the magnets are in the upper part.

In order to create an optimal gap between the coil and the magneto, a special template must be used. It is impractical to buy it for a single use, therefore, as an alternative, you can use a business card or a small calendar, as well as an A4 paper sheet folded in four. A strip cut from a plastic bottle or other available materials that have the required thickness is also suitable. The optimal distance is usually indicated in the user manual. The selected item must be placed between the magnets and the coil.

The coil will then be attracted to the flywheel by the magnetic field. While holding the magneto in this position, you need to tighten the fasteners that fix it, and then pull out the business card. After that, you need to turn the flywheel several times to make sure that it does not touch the coil at all. The process is over. the lawnmower’s ignition is on. You can learn more about the process of adjusting the trimmer ignition system on the Internet, where many videos on this topic are available.