What Should Be The Gap Of The Magneto Trimmer

Ignition module

Inoperability of the SZ chainsaw is the most common reason why the engine of the tool will NOT start. It is recommended in most cases to start troubleshooting from here.

Here’s what to do:

  • First of all, carefully check the spark plug, carefully threw off the armored wires from the head and unscrew the plug from the socket using a special key;
  • The second is to check the spark supply with the help of the Dergan starter when you put the caps of the armored wire on the candle;
  • Checking the gap is the main topic of our article (more details below).

So, a spark plug malfunction will clearly indicate its phlegm. A wet spark device for igniting the fuel-air mixture indicates that there is an excess of fuel in the system, the carburetor is incorrectly tuned, or there are problems in the SZ.

The candle is checked only after drying. That is, it must be thoroughly cleaned with a napkin, it will dry the ICE fillings, block the feed, and then start the starter a couple of times so that the excess combustible mixture comes out.

Then the spark device is put in place and everything is checked again.

In general, a spark device can tell a lot about the entire ignition system. If black carbon is observed on the candle, then this indicates violations in the communications of the gasoline mixture supply. Here either the ratio of gasoline and oil is violated, or the carburetor needs to be readjusted. In some cases, this also happens due to low-quality oil.

A dirty candle is cleaned of black carbon with a needle or some other sharp object. Then the electrode is cleaned with sandpaper (zero), until a metallic sheen appears. The spark device is returned to its place, everything is checked again.

Next step: checking the spark supply. The skirt is brought to the cylinder by the spark device, the starter is started. If a bluish spark jumps at a distance of 2-3 mm, everything is fine. A spark distance of 0.5-1 mm is already considered a malfunction. There may be no spark at all, and this is also a big problem. Perhaps this is a wire break.

And now we come to the topic of our article. The chainsaw may NOT start due to the gap between the ignition and flywheel magneto. This very gap should be within 0.2 mm. It is very simple to check: a special gasket is placed between the flywheel and Babina. If it comes in normally, not too loose and tight, then the gap is normal.

The flywheel itself dust is round, and checking the clearance with a conventional feeler gauge is impossible. The clearance would be more qualified using a special template, but it is not always possible to acquire it. And not everyone can afford to buy a template that is not cheap for a single use.

However, instead of a foreign template, you can use a cut-out strip from a plastic container for 1-2 liters of juice.

A homemade template is put like this:

  • Ignition fixing bolts are loosened;
  • A plate is inserted between the flywheel and Babina;
  • Bolts are tightened.

About the chainsaw and its inoperability

Chainsaw. The installation itself is not that difficult. But to have the smallest initial knowledge is extremely important in order to find and eliminate any defect.

Modern electronics has progressed so much that it has revolutionized the world of instruments. Saws of our days are light and at the same time powerful, equipped with electronic ignition systems ESZ.

Not long ago, dust ignition systems were cam-type. This carried a lot of disadvantages: heaviness, complexity, high cost and much more. And the main drawback of the archaic ignition system is the difficulty of the plant. Some systems of models could not generate dust at all, enough spark to flash at crankshaft speed.

Modern systems are nearly fail-safe. Dust models are lightweight and durable, the reel is made more professionally and will serve its life almost flawlessly. However, there are also problems, but in most cases they can be corrected on their own.

Consider the main types of chainsaw malfunctions associated with the flywheel and ignition system.

As a rule, the most common ailment of modern chainsaws is the absence of a supply spark. This also directly depends on the shift in the clearance (gap) between Babina and the flywheel.

Common installation failures are always associated with internal combustion engines. Problems arise in the fuel ignition system, the fuel intake module, in the internal elements of the engine itself.

As for the second units of the chainsaw, malfunctions arise there, as a rule, due to failures of the brake mechanism, poor lubrication, etc.

If startup difficulties are associated with the engine, then the following symptoms are most often observed:

  • The motor does not develop the necessary power;
  • DOES NOT start at all;
  • It starts up, but quickly stalls;
  • Functioning unstable.

As always, experts recommend identifying fault factors in a way of elimination. In other words, you need to go through the chain, diagnosing each node, each link.

The gap between the ignition coil and the flywheel of the chainsaw

Internal combustion engines are installed not only on cars or motorcycles. They are widely used in various tools, such as a chainsaw or a trimmer. In the event of their malfunction, poor start-up, it is often enough to establish the correct clearance between the flywheel and the ignition coil.

How to check the magneto of a chainsaw

Magneto, woman, module is an ignition coil. It may have nothing to do with tool failures at all, and the reason is lurking only in the gap or in another. But in some cases, it is she who becomes a factor in violation.

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To check the woman herself, you should also, as in the above case, use the method of excluding components from the chain. Or in other words:

  • Visually assess the condition of the bobbin case for cracks and other visible defects;
  • Check the cleanliness of current communications of various nodes and elements;
  • Diagnose the insulation and serviceability of the armored wiring, the reliability of fixing the fasteners, the absence of rust, etc.
  • Visually assess the condition of the spark device cap;
  • Checking the condition of the candle;
  • Diagnostics of the circuit breaker, which is especially important for Chinese-made chainsaws.

Again, as in the case described above, certain points are excluded from this chain, thus the cause of the problem is found.

The woman herself is investigated as follows.

  • The magneto resistance is measured. However, this option is not always applicable, since you first need to know the resistance parameters. In addition, in order to generate the required HE pulse, it is necessary to separate the characteristics of the various semiconductor elements. A symptom of a malfunction, as a rule, is ringing through the BB wire and minus. Should show either “open circuit” or high resistance.
  • The check can be carried out as follows. use a device that checks for the presence of a spark. It is installed in the break of the chain between the BB guide and the candles. The disadvantage of this method is that the device is so very expensive, it is used mostly in serious repair services.
  • “Dedovsk” test method, which will allow you to save on expensive devices. It is used at your own peril and risk when there are no other options. The method of checking is that the cap is thrown off the candle, a carnation is inserted into it. The candle is re-inserted. The stud should be 6-7 mm from the cylinder. The chainsaw starts up. The spark is being investigated: it should be bright blue, if not, then this is a sign of a malfunction.

“Dedovsk” method of checking the bobbin has many disadvantages. First of all, this applies to electrical components in the system, which can easily deteriorate. The distance between the cylinder and the stud may vary depending on different tool models.

As for tuning the magneto, it boils down to examining the groove on the flywheel. POP in most of the current models does not need to be regulated dust. But it is possible to determine its exposure only by the angle between the mark after the groove on the flywheel and the magnets installed, again, on the flywheel.

Competently and accurately set the gap between the magneto and the flywheel. that’s what is more important.

You should know that the headstock on chainsaw systems is installed in the fan fuselage near the flywheel. The coil, in contact with the flywheel magnet, produces energy for a spark.

Replacing the coil itself will be much more difficult, since the installation site is too inconvenient. The installation of a new bobbin should be carried out so that the base of the coil is at a distance of 1-1.5 mm above the flywheel magnets.

In some cases it is recommended to check the crankshaft bearing for play as well.

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Chainsaw ignition device:

  • Magneto: a device that converts mechanical energy into electrical energy, provides a current pulse to the spark plug of the chainsaw;
  • Spark plug: designed to ignite the fuel-air mixture through a discharge that occurs between the electrodes;
  • Electric cable;
  • Engine shutdown button.

Candles are spark plugs, arc plugs, incandescent plugs and catalytic plugs. Chainsaw devices use spark plugs for 2-stroke engines. A schematic diagram of the ignition of a chainsaw is shown in the image.

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.

Ignition timing

The mechanical device and the factory setting of the magneto ensure that the discharge time of the spark plug matches the optimal position of the moving piston. For four-stroke gasoline engines, spark slip must occur even before the piston reaches top dead center. this is explained by the fact that the process of complete combustion of the air-fuel mixture takes a certain amount of time. The speed of movement of engine parts is comparable to the speed of fuel ignition, so the piston, from the moment of spark breakthrough to the moment the burning gases create extremely high pressure, has time to travel a certain distance.

There is an ignition timing for each engine. It is equal to the crank angle expressed in degrees of rotation from the moment of breakdown in the interelectrode space of the spark plug until the moment when the piston is at top dead center. This indicator depends on many parameters, including the design features of the engine and the properties of the fuel mixture.

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In practice, during the mass production of an engine at the factory, individual adjustment of the ignition of each product is not made, but the corresponding marks are set on the rotating parts, which must be aligned during installation.

In what cases is ignition adjustment required? There are the main symptoms of a system failure:

  • The engine will not start;
  • The motor works, but with noticeable interruptions;
  • There is a decrease in tool power.

In THESE cases, do not rush to contact the service center. Try to adjust the ignition yourself first.

The procedure for checking and adjusting the correct operation of the engine

The most vulnerable element of a carburetor engine is the spark plug. It also allows you to judge the probable causes of malfunction of SEPARATE gasoline engine units. The following procedure is recommended.

    Dismantle the spark plug and inspect it. A dry candle with a slight brown tint of the electrodes can be considered serviceable.

Spark plug carbon

Chainsaw ignition coil

When installing a new electrical module on the engine, the magneto gap must be adjusted. The optimal distance between the flywheel and the ignition coil is 0.2-0.4 mm for most chainsaws.

Clearance between magneto and flywheel

To be sure, it is recommended to carefully study the documentation for the purchased model and follow the manufacturer’s requirements.

With such a small gap, it will NOT be possible to use an available measuring tool for direct measurement. In practice, a Husqvarna saw uses a template in the form of a spacer cut from thin, flexible sheet material of the required thickness. It is clamped in the space between the flywheel and the coil when it is installed, and then pulled out.

To avoid the need for resorting to ignition adjustment, operate the tool carefully, avoiding impacts. In particular, this applies to chainsaws with electronic chips in the ignition system, since they are very sensitive to mechanical damage.

What Should Be The Gap Of The Magneto Trimmer

How to set the ignition on a chainsaw?

It is required to adjust the clearance between the flywheel and the ignition coil on the chainsaw when the tool does not start. Immediately before adjusting, you need to check the condition of the spark plug. To do this, you need to remove the wires from the head and carefully unscrew the part from the socket with a special key. If the candle is NOT wet, and small light spots of oil are visible on its ceramic walls, then you need to proceed to the next stage of checking.

To do this, you need to put a cap with standard wiring on the candle and pull the starter rope sharply several times. If, at the same time, a spark has not occurred, then you should proceed to adjusting the gap between the flywheel and the magneto.

Infringement of the clearance between these parts of the chainsaw may cause careless handling of the tool. In standard form, the distance between magneto and flywheel should not be more than 0.2 mm. It is quite easy to check this value. To do this, you will need to place a special gasket between the elements. If it freely enters the space between the elements, then the gap is set correctly.

Many craftsmen claim that it is possible to correctly adjust the ignition on a chainsaw only using a template. However, every tool owner can afford to buy a disposable product at a fairly high price. Many gardeners use homemade stripe templates cut from a flat plastic juice container.

Further adjustment of the ignition of the chainsaw is performed in the following order:

  • First you need to loosen the system fixing bolts;
  • After that, a template should be inserted between the standard ignition coil and the built-in flywheel;
  • At the end, the fixing adjustment bolts will need to be tightened.

After adjusting the gap, it remains to assemble the chainsaw and continue its operation.

Chainsaw ignition

For a gasoline saw to start running stably at idle, the fuel located in the factory cylinder of its power unit must ignite. For this, a standard ignition system is provided in the basic configuration of any branded chain tool. Its serviceability largely depends on the ability of the internal combustion engine to make the first cold start and steadily gain momentum when the operator presses the gas trigger. The ignition of a commercial saw is distinguished by a simple device and a constant operating principle. Having studied their features, it will be easier for the operator to perform maintenance and self-repair of the unit.

Ignition adjustment

As we have already noted, you can adjust the ignition system both in the workshop and at home. To do this, you need ordinary wrenches, a screwdriver and a 0.4 mm dipstick (you can make a dipstick with your own hands from scrap materials. plain copier paper, a plastic bottle, etc.).

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.

Yaroslav Stembitsky, 37 years old, Zhytomyr region

“After the winter the chainsaw didn’t start. For a long time as a starter Dergal. the hand is tired, but It does not start. Then he guessed the candle Vykrut and check for a spark. dull, there is nothing. He took off the protective cover, looked. the gap is normal. Collected everything, and she won’t start again. Day digging, Until I thought of checking the contact on the candle. It turned out that the spring popped out. Why and when. I don’t know. “

How the trimmer ignition system works

The ignition system of a two-stroke internal combustion engine consists of 2 parts: 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. Also on one side of the flywheel are permanent magnets, shown in the figure by an arrow.

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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 for trim tabs

On gasoline trimmers, both two-stroke internal combustion engines (ICE) and four-stroke are used. But the ignition system in them is NOT 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 will 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 reach the top dead center (TDC) just a little. 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 (this is mainly due to the displacement of the flywheel on the shaft until 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 trimmer: the piston, after compression of the fuel, which has not ignited, goes down, and at this moment a spark appears. In this case, the engine will either not start, or will significantly lose power and gain speed poorly.

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 to check the health of a magneto

Magneto is the main part of the engine ignition system and is a coil with primary and secondary windings located around the core. Often, due to a malfunction of the magneto, the spark on the spark plug disappears and the fuel does not ignite. To check the coil, you need to use a tester, and follow these steps.

  • On testers, go to the resistance measurement mode, you need to set 200 ohms. This method will check the primary winding.
  • Connect one electrode of the tester to “mass” coil, and the second to the contact coming out of the magneto. Normally, the resistance should be between 0.4 and 2 ohms.
  • To check the secondary winding, you need to set the device switch to 20 kOhm. Further, one probe of the device is inserted into the candle cap, and the second is connected to “mass”. Normally, resistance indicators should be in the range of 4-6 kΩ and above (depending on the model).

If you have a tester, then you can use the following method; it is very careful so that the electrode does NOT touch the cylinder, otherwise the coil will burn out.

  • Remove the cap from the candle. It is not necessary to unscrew the candle in order to maintain compression.
  • You must insert a nail into the cap without a cap. The nail should be of such a diameter that it holds well in the cap.
  • Tie the cap with the nail to the cylinder using a dielectric so that the gap between the electrode and the cylinder body is between 5.5 and 7 mm (but in no way touches “mass”).
  • Using the starter Let’s simulate the engine start several times. The ignition button must be on.
  • Observe if a spark appears and what color it has.

Normally, the spark should be strong, white or bluish in color. If the spark is weak, and its color is orange or yellow, this indicates a faulty magneto.

Also consider the fact that sometimes cold magneto can give a good spark. But after heating, due to internal faults, it ceases to produce current. As soon as the coil cools down, the trimmer starts again and runs for a while until the magneto does NOT heat up again. This coil needs to be replaced.

Ignition adjustment algorithm

Trimmer ignition is quite simple to adjust.

    Remove the engine cover from the engine by unscrewing all the bolts holding it. For example, on Patriot (Patriot) PT 2540 lawn mowers, to remove the cover, you will need to Unscrew the air filter housing, and remove it from the latches with a flat screwdriver. After that, the plastic case can be easily removed.

  • Using a screwdriver, unscrew the 2 bolts (completely unscrew it NOT required) holding the magneto.
  • Turn the handwheel so the magnets are at the top.
  • Further, in order to correctly set the best gap between the flywheel and the coil, you can use an ordinary business card or calendar. If you have neither one nor the other at hand, then, to set up the ignition, you can use a letter of A4 paper by folding it 2 times (in total, you will get a thickness of 4 sheets). This thickness will be enough to get the optimal clearance and adjust the ignition. Insert a business card or paper between the spool and the magnets.
  • The magnetic field will pull the coil towards the flywheel. While holding the magneto in this position with your fingers, tighten the bolts that hold it.
  • Remove the business card. After that, the trimmer ignition will be adjusted.