How to install the ignition coil to the trimmer

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.

install, ignition, coil, trimmer

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.

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.

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.

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.

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.

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.

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.

Features of adjustment on different models of trimmers

The ignition system works in a similar way on different brands of technology, so the adjustment process will look the same. Differences, if any, are insignificant. They are mainly related to the disassembly of equipment. For example, removing the cover from the engine on different trimmers is done with some differences. So, on Patriot devices, you first need to unscrew the bolts and disconnect the air filter housing with a slotted screwdriver. After that, it will be very easy to remove the plastic cover. A detailed diagram and device of a trimmer of a particular model are usually shown in the instruction manual of the tool.

So, you can do the ignition adjustment for a gasoline trimmer with your own hands. This process is not difficult if you know the correct procedure. But first you need to exclude possible malfunctions of other components and parts, for example, spark plugs or magneto, which may be the reason for the lack of engine start of the lawn mowers. However, disassembling equipment of different brands, you need to take into account the likely differences in design, which are described in detail in the user manual.

  • What do you need?
  • Line replacement process
  • Video
  • Useful articles

What do you need?

How to wind the line onto the trimmer spool

The line in the trimmer head can run out at the most inopportune moment when the work is in full swing. So that the replacement of the fishing line does not take much time and does not have to go through the instructions for a long time, we recommend that you theoretically familiarize yourself with this process in advance. From our article you will learn all the subtleties, starting with the choice of consumables and ending with winding on spools of different types.

Line replacement process

Line selection

For each trimmer, the manufacturer recommends a fishing line or cord of a certain diameter. a reel is made for it. It can be from 1.2 to 4 mm: you need to look at the instructions for what line sizes are acceptable for your tool. For example, many trimmers have a maximum value of 3 mm (recommended for tough grass). a thicker cord cannot be fitted. For cutting young, soft vegetation, a thin line with a diameter of 1.2. 1.6 mm is suitable. Also, when choosing, pay attention to the structure of the cord: round is the most durable and suitable for coarse grass, curly. for soft, twisted or notched. for thin stems. Depending on what kind of grass grows on the site. lawn or weed, buy the appropriate consumable. The length of the winding can be from several tens to several hundred meters, and its price depends on this. You need to proceed from the amount of work to be done. If the trimmer is used in a private household, there is no need to buy a roll over 100 m.

It is important to know! Buy only branded line recommended by the trimmer manufacturer. It is made of high-quality materials and is durable. it will cut the grass perfectly and not wear out so quickly.

For one threading of the line into the bobbin, a length of 2 to 4 m is required. it all depends on its thickness and the manufacturer’s recommendations. If you wind more, the movement of the line will be difficult, and in the process of work, you may have problems pulling out new ends. Unwind the required amount and cut with a knife.

Helpful Hint: Place a piece of cord in water for 30 minutes, then it will become more elastic and stronger.

Removing the spool from the spit

To insert the line into the trimmer head, you must remove it from the tool. Depending on the design, this can be done by pressing the latches or unwinding the lamb. Pay attention to the direction of the thread. right or left. and rotate the wing depending on this. Usually the direction of rotation is indicated by an arrow on the trimmer head housing. It is recommended to carry out this operation with gloves. fingers will not slip, and hands will not get dirty.

Dismantling the mowing head

The line is wound on a spool, which is hidden in the trimmer head housing. To get to it, you need to disassemble the element. On the case there are latches-latches, when you press them, the case cover can be easily removed. Sometimes disassembly is carried out by untwisting the case.

Be careful! Remember in what order the elements are installed, how the spring and the fixing screw are located inside the head. Stack all the parts neatly in one place so that nothing gets lost and there are no problems during assembly.

Line winding

Trimmer heads differ in structure, reel type and line pulling principle. Having disassembled the case, you will see the spool and determine what type it belongs to. There are products with a middle edge that divides the reel into a top and bottom for each end of the line. In products without it, the line winding is solid. To make the process clearer, we suggest using the table.

READ  How To Put The Line On The Trimmer Spool

Winding line on reels of different types

With dividing edge

Without dividing board

We have described how to wind the line into the reel of a double-barbed trimmer. This is the most common option. But there are other ways as well. For example, if there is one antenna in the mowing head, then winding is carried out without folding the line. Rotate in the direction indicated on the bobbin body, and the free end of the cord is temporarily fixed in the slot on the body. For trimmers with four antennae, four short sections are consumable, which are inserted in turn into the holes of an already assembled head.

Helpful hint: when winding the line, be careful not to pull it tight, so that it does not sit very tightly in the reel. It is necessary to ensure its free movement for subsequent pulling.

Assembling the trimmer head

After the line is wound on the spool, it is necessary to assemble the body. Position the spool so that the ends of the line can be pulled into the trimmer head outlets. The slots in the spool where they were temporarily inserted will prevent them from slipping out. If there are no such slots, support the ends with your fingers as you insert the coil into the body. After pulling the free ends into the outlet openings, close the lid and secure it with latches or twist. Place the mowing head on the trimmer and pull out the ends of the line to the required length so that they do not touch the protective cover during operation. Done! You can get to work!

The device and operation of the bobbin

The modern bobbin is a simplified version of the Rumkorf induction coil. It was named after the inventor of German origin. Heinrich Rumkorf, who first patented in 1851 a device that converts constant low voltage into alternating high.

To understand the principle of operation, you need to know the structure of the ignition coil and the basics of electronics.

This is a traditional, common VAZ ignition coil, which has been used for a long time in many other cars. In fact, it is a pulse high-voltage transformer. A secondary winding is wound on a core designed to enhance the magnetic field with a thin wire, it can contain up to thirty thousand turns of wire.

On top of the secondary winding there is a primary of a thicker wire and with fewer turns (100-300).

The windings are connected to each other at one end, the second end of the primary is connected to the batteries, the secondary winding is connected to the voltage distributor with its free end. The common point of the winding coil is connected to a voltage switch. This whole structure is covered by a protective case.

In the initial state, a direct current flows through the “primary”. When a spark needs to be formed, the circuit is broken by a switch or distributor. This leads to the formation of a high voltage in the secondary winding. The voltage goes to the spark plug of the desired cylinder, where a spark is formed, causing the combustion of the fuel mixture. High-voltage wires were used to connect the spark plugs to the distributor.

Single-pin design is not the only one possible, there are other options.

  • Double spark. The tandem system is used for cylinders that operate in one phase. Suppose that compression occurs in the first cylinder and a spark is needed for ignition, and in the fourth phase of the purge and an idle spark is formed there.
  • Three-spark. The principle of operation is the same as that of a two-output, only similar ones are used on 6 cylinder engines.
  • Individual. Each spark plug has its own ignition coil. In this case, the windings are reversed. the primary is under the secondary.

How to check the ignition coil (bobbin) on a car

For a gasoline internal combustion engine, the ignition system is one of the defining ones, although it is difficult to single out any main unit in the car. You can’t go without a motor, but it’s also impossible without a wheel.

The ignition coil creates a high voltage, without which the formation of a spark and ignition of the fuel-air mixture in the cylinders of a gasoline engine is impossible.

  • Briefly about ignition
  • The device and operation of the bobbin
  • How to check the ignition coil
  • With a multimeter
  • other methods
  • Connecting the ignition coil
  • Output

other methods

Another way, especially relevant for old cars, including VAZs, is to check the spark. For this, the central high-voltage wire is placed at a distance of 5-7 mm from the motor housing. If, when trying to start the car, a blue or bright purple spark jumps, the reel is working normally. If the color of the spark is lighter, yellow, or it is absent altogether, this may serve as confirmation of its breakage, or a wire malfunction.

There is an easy way to test a system with individual coils. If the engine troit, you just need to disconnect the power to the coils one by one while the engine is running. They disconnected the connector and the sound changed (the machine doubled up). the coil is in order. The sound remains the same. the spark does not come to the candle in this cylinder.

True, the problem may be in the candle itself, therefore, for the purity of the experiment, you should swap the candle from this cylinder with any other.

Briefly about ignition

To understand why there is a bobbin in a car (this is a popular name), and what part it takes in ensuring movement, one must at least generally understand the structure of ignition systems.

A simplified diagram of the bobbin operation is shown below.

The positive terminal of the coil is connected to the positive terminal of the battery, and the other terminal is connected to the voltage distributor. This connection scheme is classic and is widely used on cars of the VAZ family. To complete the picture, a number of clarifications must be made:

Mechanical devices were used in old cars: on the VAZ 2106 and the like, but now they are almost completely replaced by electronic.

Connecting the ignition coil

If during dismantling you did not remember and did not note which wire went to which terminal, the ignition coil connection diagram is as follows. Power is supplied to the terminal with the sign or letter B (battery) from the battery, the switch is connected to the letter K. The colors of the wires in cars may differ, so the easiest way is to track which one is going where.

Correct connection is important, and in case of polarity violation, the reel itself, distributor, switch can be damaged.

With a multimeter

Using a multimeter, you can check the ignition coil in 3 parameters:

  • primary winding resistance;
  • secondary winding resistance;
  • short circuit (insulation breakdown).

It should be noted that in this way only an individual ignition coil can be checked. Doubles are arranged differently, and you need to know the layout of the “primary” and “secondary”.

We check the primary winding by connecting the probes to contacts B and K.

Coil type Resistance, Ohm
VAZ 2106 (contact system) 3.07-3.5
27.3705 (contactless, M, R) 0.45 ± 0.05
3122.3705 (C, Z) 0.43 ± 0.04
8352.12 (M, R) 0.42 ± 0.05
027.3705 (M, R) 0.43 ± 0.04
27.3707-01 (M, R) 0.42 ± 0.05
ATE1721 (M, R) 0.43 ± 0.05
M. oil-filled
C. dry
Р. open magnetic circuit
З. closed magnetic circuit

Measuring the “secondary”, we connect one probe to contact B, and the second to the high-voltage output.

Coil type Resistance, KOhm
VAZ 2106 (contact system) 5.4-9.2
27.3705 (contactless, M, R) 5 ± 1
3122.3705 (C, Z) 4.08 ± 0.4
8352.12 (M, R) 5 ± 1
027.3705 (M, R) 5 ± 1
27.3707-01 (M, R) 5 ± 1
ATE1721 (M, R) 5 ± 1

The insulation is measured through terminal B and the coil body. The readings of the device must be at least 50 Mohm.

It is far from always that a simple motorist has a multimeter at hand and experience in using it; on a long journey, checking the ignition coil in this way is also not available.

How to check the ignition coil

The main parameter by which the performance of the bobbin is determined is the resistance of the windings. There are averaged indicators that indicate its serviceability. Although deviations from the norm are not always an indicator of a malfunction.

How to install the ignition coil to the trimmer


Diagram of a contactless ignition system VAZ 2106:
1. ignition distributor sensor; 2. spark plugs; 3. screen; 4. contactless sensor; 5. ignition coil; 6. generator; 7. ignition switch; 8. storage battery; 9. switch

Ignition system malfunctions by reference.

How to expose

For work, you need a 12-volt control light, a 13-key and a crankshaft key:

You need to set the ignition on the idle engine, with the “negative” battery terminal disconnected.

Set the piston of the first cylinder of the internal combustion engine to the ignition position. To do this, you need to unscrew the spark plug from it. We plug the spark plug hole with a finger and at the same time turn the crankshaft clockwise with a wrench.

When there is a compression stroke, the air under pressure will begin to push the finger strongly. this is what you need.

Now it is important to clearly align the mark on the pulley with the second one, which you are looking for on the timing cover. The mark in the middle means that the ignition advance is set by 5 degrees.

Ryobi String Trimmer Ignition Coil Replacement #291337001

It happens that some people cannot find their tags. But in fact, there are always labels. Just wipe the surfaces well with a metal brush, add light.

After setting the marks, you can remove the key. Wrap the removed plug back and connect the armored wire.

The next stage of work will be to determine the ignition moment:

Before starting, connect the negative terminal of the battery.

Using a 13 key, slightly loosen the fastening nut of the ignition distributor.

Here you will need a prepared control light with two wires. We connect one terminal to the “mass”, the second. to the low-voltage ignition coil.

Turn on the ignition by turning the key to the “I” position.

It is necessary to carefully turn the ignition distributor housing clockwise until the control lamp goes out.

After that, it is necessary to smoothly turn the distributor rotor counterclockwise. until the contact is open and the light turns on again.

Now you need to tighten the mount and check the behavior of the machine on the go.


first of all, it is necessary to set the TDC. 4 cylinders (we look at the position of the slider), this must be done by turning the crankshaft ratchet to the mark on the pulley, we combine marks 4 and 3 in the figure);

dismantle the distributor, candles and the coil (remembering the color of the wires suitable for the ignition coil);

we lay new wiring;

install a new high-voltage ignition coil;

we put the distributor exactly as the old one was (the installation of electronic ignition of vaz 2106,2103, 2107 with engines of 1.5 and 1.6 liters is slightly different from other models. These engines have different cylinder block heights and, accordingly, different length of the distributor drive shaft);

we fix the switch (it is advisable to find a place on the shield of the engine compartment);

we screw in the candles and put on high voltage wires (operating procedure 1-3-4-2);

we connect the wiring as in the diagram:

Electronic ignition for vaz 2106

Each owner of the legendary classic model VAZ 2106 is well aware of all the problems associated with the operation of this car, since in most cases he eliminates them on his own. Such problems also include malfunctions of the contact (cam) ignition system of the VAZ 2106. Constantly burning contacts required cleaning and adjustment, because of the backlash of the bearing and the distributor sleeve, the engine operation resembled a “shake”, especially at idle. The electronic ignition system is designed to solve all these emerging problems.


Closed contact angle correction

Trimmer Repair. Replacing the Ignition Coil (Ryobi Part # 850080001)

The ignition adjustment of the VAZ 2106 begins with the simplest operation of removing the distributor cover, then the crankshaft turns until the maximum distance between it and the distributor is reached. Following this, they begin to unscrew the screws that fix the contact group on the bearing plate and between the contacts, a probe is introduced to determine and select the optimal position for the group. Ideally, everything is determined by the applied force to move the stylus, which should be minimal, after finding a section that meets this requirement, the position of the group is fixed by tightening the screws. The size of the gap is also important for its determination, the thickness of the stylus should be 0.44 millimeters. It is the adjustment of the gap that provides the required value of the angle of closed contacts, its optimal value is 55 ± 3 °.

READ  How to Replace a Bobbin on a Trimmer

If the parameters correspond to the norm, then you can proceed to the second stage, which consists in adjusting the advancing ignition angle. To begin with, let us determine that the distributor breaker in the type of engine under consideration needs to implement the opening moment simultaneously with the spark in the first cylinder. This provides for the advance of the top dead center of the piston stroke for the first cylinder by 0 ± 1 °.

Correction of the lead angle using a stroboscope

There are several ways to adjust this indicator, on which the correct ignition adjustment of the VAZ 2106 as a whole largely depends. The most efficient way to cope with this task is a method involving the use of a stroboscope. The device must be connected to the automotive electrical network, while it is necessary to dismantle and plug the vacuum correction hose from the distributor. Following this, the engine is warmed up, until it holds idle speed, followed by loosening the bolt responsible for fixing the distributor housing.

The light emitted by the stroboscope is directed to the crankshaft pulley, rotation of the distributor housing will allow to achieve a position that ensures that the visible position of the mark on the pulley is opposite the corresponding marks applied to the timing cover. In this position, the distributor body is fixed by tightening it with bolts. The presence of idle speed of the power unit during the adjustment process is of decisive importance. If the revolutions are higher, a centrifugal regulator will take part in the work, which will distort the adjustment results.

Problem prevention

Often, breakdowns of the ignition coils are associated with a short circuit or breakage of the windings and mechanical damage to the magneto case. This is due to strong shocks, liquid ingress and oxidation, and overheating. If such incidents are avoided, there is no need to worry about the integrity of the ignition coil.

Important! To prevent regular failure of the spark plugs. one of the most important components of the ignition system. you need to fill up with high-quality fuel. Bad fuel spoils these parts.

One of the magneto assemblies that regularly suffer from use are the high voltage wires through which the spark plugs receive current from the ignition module. They have a long service life, but they are damaged by the users themselves by careless handling when replacing candles, inadvertently pulling on the wire itself, and not on the tip. Another problem that can happen to them is moisture ingress and oxidation or damage to the insulation. By carefully pulling out the plug and avoiding liquid penetration into the instrument, these problems can be avoided.

So, the repair of the ignition coil is not very difficult and can be carried out by the user independently, but subject to the above procedure for disassembling and replacing the magneto or breaker contacts.

Disassembling magneto

Disassembling the magneto is very simple. First you need to remove this device from the engine and clean it, removing oil particles and dirt. Further, since the ignition timing machine is securely fastened, you need to unscrew the nut, and then remove the part and pull the key out of the groove. The cover is fixed with four screws; to remove it, you need to unscrew and remove the fasteners. Then you need to pull the magneto rotor out of the case, unscrew the pins holding the transformer, and get it out. And to collect the magneto, you need to follow the steps described above in reverse order.

Typical problems. causes

The faults that most often occur with magneto are typical for trimmers from different manufacturers. As a rule, this is a weak spark or its absence, as well as the presence of interruptions in this process.

Functional check

Before starting to diagnose magneto, you need to make sure that the problem is actually in this node. To do this, you need to check the entire chain and make sure that there are no other reasons for the breakage of the trimmer.

  • First, you should carefully inspect the coil for cracks and other external defects on the case. Next, you need to examine all the elements and nodes that conduct current, and make sure that they are clean.
  • The next step is to inspect the high voltage wires. They must be in good working order and securely attached to the contacts, free from rust and with intact insulation.
  • The next step is to check the plug cap. As a result of careless actions, the user often tears it off the high-voltage wire, and then improvises and creates a homemade mount. You need to understand that any poor-quality connection in this place significantly reduces the power of the electric arc of the candle.
  • Then you should make sure that the candle itself is in good order. Filling the mower with poor quality gasoline will significantly reduce the life of this part. In addition, it can be flooded or have a large carbon deposit that interferes with operation. Sometimes the candle even sticks and does not unscrew.
  • Next, you need to inspect the circuit breaker. On trimmers and chainsaws made in China, it often breaks down.

After completing all these steps and excluding the listed nodes from the list of possible causes of failure, you should proceed to checking the coil. This can be done in several ways.

Magneto. design and operating principle

The purpose of the ignition coil is to convert the rotational energy into a high-voltage discharge and form a spark that ignites the fuel mixture. In an internal combustion engine, this part is called a magneto, since in it an alternating current is generated from the rotation of a permanent magnetic rotor or an armature.

Magneto structurally consists of two windings: high and low voltage. A capacitor with breaker contacts is connected in parallel to the latter. Whereas the leads of the high voltage winding are connected to the candle and the body. Both of them are wound on a core, between the poles of which a rotating magnet is installed, magnetized longitudinally.

On a note! The whole structure looks like a large coil mounted on a U-shaped core.

Replacing breaker contacts

After disassembling the magneto, it is necessary to remove the old breaker contacts and install the new ones correctly. To do this, you must:

  • move the latch, remove the cover from the breaker;
  • unscrew the screw holding the connecting wire;
  • remove the screw securing the breaker plate to the magneto cover and remove it;
  • get the screw securing the breaker spring;
  • remove the lock washer from the axle, and then the lever with the cushion assembly, which it holds;
  • unscrew the screw securing the contact post, remove the part from the axle.

Assemble the assembly with new contacts in the reverse order.

On a note! Despite the ease of operation, most often trimmer owners prefer to simply replace the magneto with a new one.

Insufficient sparking

The weak spark on the magneto is caused by a damaged capacitor. To eliminate the breakdown, it is necessary to replace the failed part.

Trimmer ignition coil. faults and repairs

Lawn mowers are a popular seasonal tool designed to remove unwanted vegetation from your home. Like any other technique, these devices break down periodically. Repairing the trimmer ignition coil is one of the popular problems common to gasoline braids. The ignition system itself is designed in the same way on two- and four-stroke internal combustion engines, so the elimination of breakdowns is performed almost the same for tools from different manufacturers, be it Lux, Huter, Husqvarna or another brand. Ways to restore the performance of the ignition coil or replace it with a new one. in the material below.

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.

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.

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.

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.

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

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 the tester, after switching to the resistance measurement mode, you need to set 200 ohms. In this way, the primary winding will be checked.
  • Connect one electrode of the tester to coil ground and the other to the lead coming out of the magneto. Normally, the resistance should be between 0.4 and 2 ohms.
  • To check the secondary winding, you will need to set the device switch to 20 ohms. Further, one probe of the device is inserted into the candle cap, and the second is connected to the “mass”. Normally, resistance indicators should be in the range from 4-6 kΩ and above (depending on the model).

When the circuit is open, the device will show infinity, and when closed. 0 (zero).

If you do not have a tester, then you can use the following method, being very careful so that the electrode does not touch the cylinder, otherwise the coil will burn out.

  • Remove the cap from the candle. You do not need to unscrew the candle in order to maintain compression.
  • It is necessary to insert a nail without a cap into the cap. The nail should be of such a diameter that it adheres well to 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 case touches the “mass”).
  • Using the starter, simulate the engine start several times. The ignition button must be on.
  • Observe if a spark appears and what color it has.
READ  How to change line on a Stihl trimmer

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

You should also consider the fact that sometimes cold magneto can give a good spark. But after heating, due to internal malfunctions, it ceases to produce current. As soon as the coil cools down, the trimmer starts up again and runs for a while until the magneto warms up again. This coil needs to be replaced.

Sometimes a spark plug can cause a similar heating problem even if the coil is OK, so both parts need to be checked.

Trimmer ignition setting

Gasoline trimmers use both two-stroke internal combustion engines (ICE) and four-stroke. 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.

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 a Patriot (Patriot) PT 2540 lawn mower, to remove the cover, you will need to unscrew the air filter housing, and use a flat screwdriver to remove it from the latches. After that, the plastic case can be easily removed.

String Trimmer Ignition Coil Replacement #545046701

  • Using a screwdriver, unscrew the 2 screws (not completely unscrewed) holding the magneto.
  • Turn the handwheel so the magnets are at the top.
  • Further, in order to correctly set the best clearance between the flywheel and the coil, you can use a regular business card or calendar. If you do not have either one or the other at hand, then to set up the ignition, you can use a sheet of A4 paper by folding it 2 times (as a result, you will get a thickness of 4 sheets). This thickness will be sufficient to obtain an 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 ignition on the trimmer will be adjusted.
  • How to check the short circuit?

    How to check the short circuit yourself:

    • First you need to disconnect the power wire from the negative terminal of the battery and turn off the ignition.
    • Then open the hood and disconnect the two high voltage cables from the product. Unscrew the bolts, and also dismantle the bar together with the product. The dismantling of the second short circuit is carried out in the same way.
    • The diagnostic procedure itself is carried out using an ohmmeter, its probes are connected instead of disconnected wires. After connecting the probes, it is necessary to measure the resistance level. If the product is functional and serviceable, then the resistance level should be about 0.4-0.5 Ohm.
    • To obtain more accurate diagnostic data, you can also short-circuit the tester probes, and then again diagnose the resistance. In particular, you are now interested in the secondary winding of the device. If the device is operational, then the resulting value should be in the region of 5-7 kOhm. In the event that the diagnostics showed other values, this indicates that the short circuit needs to be replaced.

    Photogallery “Diagnostics of short circuit”

    Replacement intervals and symptoms of malfunction

    On average, the service life of modern SZ is about 20 thousand km of run. Of course, this indicator depends on many conditions. First of all, this is the quality of the part made, its operating conditions, as well as the quality of the fuel used. The last point is very important, since the use of low-quality fuel will lead to a significant reduction in the service life of the SZ.

    By what signs can you determine the malfunction of the candles:

    • If you remove the SZ from the seat, you will see its body. The presence of carbon deposits and deposits on the body of the device, in particular, on the electrode, may indicate a breakdown of the product. You can try to solve such a malfunction by cleaning, but this does not always help.
    • The presence of traces of oil in the NW. Due to oil exposure, the product cannot work effectively, therefore, malfunctions may appear in the operation of the SZ. Such devices need to be cleaned and dried, but before further use, it is necessary to determine the reason for the ingress of motor fluid on them.
    • Also, fuel traces on devices may indicate a malfunction of the SZ.
    • Another sign is that the starter has to be turned for a long time, while the motor may start after a long period of time, or it may not start at all. The same symptoms indicate a dead battery, a broken distributor, or an incorrectly working gas pump.
    • When the engine warms up, unpleasant and uncharacteristic sounds for its operation appear. They can also appear when idling.
    • Fuel consumption increased significantly during vehicle operation.
    • In addition, the amount of harmful substances in the exhaust gases has increased. Of course, this malfunction cannot be determined by eye; more thorough diagnostics is needed.
    • The traction of the vehicle has significantly weakened, its power has decreased, the engine is hardly gaining momentum.

    Candles used on cars with engines ZMZ-405, 406 and 409

    • first of all, these products have a different heat dissipation parameter;
    • in addition, their clearance is 1 mm, which is not suitable for these motors.

    Finding A14DVR devices today is not so easy, so many motorists have to look for analogues.

    So that you can choose a similar product, we suggest that you familiarize yourself with the decoding in more detail:

    • A. this beech determines the diameter, as well as the pitch of the thread D. In the original SZ, thread M141.25 is used.
    • 14 is the value of the glow number. It is considered one of the main parameters that determine the characteristics of the temperature regime of the operation of the product.
    • D is the value of the thread length. In our case, SZ are equipped with a 19 mm thread.
    • B. determines how much the thermal cone of the insulator protrudes into the very combustion chamber of the motor. Due to the protrusion of the cone, the warming up of the product is accelerated when the power unit is started, and this, in turn, provides its higher resistance to carbon formation.
    • The last symbol. P. determines the presence of a built-in resistor element in the SZ structure. Thanks to the presence of a resistor, the level of interference for radio equipment, as well as for the motor control module, is reduced. In general, the presence or absence of this element in the SZ design will in no way affect the functionality and quality of spark formation when starting the internal combustion engine.

    Features of the ignition coil device

    The ignition coil (KZ) is a small transformer. A primary winding is wound on its magnetic core, and on top of it, in sections, a secondary winding is installed. Both of them are installed in a plastic case, and the space between these components is filled with thermosetting polymer resin.

    Also on the case there are low and high voltage contacts for connecting the device. In accordance with the connection diagram of the coils, low voltage pulses are supplied to the device from the control unit. Once inside the device, these pulses are converted into high-voltage charges, which, in turn, are fed to the SZ. The discharge is carried out simultaneously on two SZ (video author. Alexander Terekhin).

    The main aspects of the ignition installation

    The main aspects to consider when installing ignition by tags:

    • First you need to dismantle the front cover of the cylinder head, for this you need to unscrew four screws 12. In some modifications of engines, dismantling also involves removing the fuel pump.
    • Then the upper hydraulic tensioner located in the head is dismantled; for this, two screws fixing the cover are unscrewed.
    • Next, the chain dampers are removed. the middle one, as well as the upper one; for this, two screws are unscrewed, which fix them.
    • After that, the camshaft sprockets are dismantled. The shafts themselves need to be fixed with a 27 key, while unscrewing the screws that fix them. In versions of motors 4063.10, the camshaft sprocket is dismantled together with the eccentric of the fuel pump drive.
    • In accordance with the jig installed on the sprocket, six holes should be drilled in each of them. Their angular displacements should be 2, 30, 5, 00, 7 and 30 degrees from the set position of the factory hole, which is located along the axis of symmetry.
    • In the event that, when adjusting the phases, it will be necessary to turn the camshaft clockwise, then the sprocket itself should be mounted on one of the additional holes with a positive offset. It is located to the right of the standard hole.

    Typical unit malfunctions and ways to eliminate them

    A malfunction in the operation of the short circuit can happen for the following reasons:

    • Short circuit inside the system, which could cause the device to overheat. If the operating temperature exceeds 150 degrees, the product will fail irrevocably.
    • The second reason is a power failure from the car’s electrical network. As you know, for the normal operation of electrical devices, the voltage level in the on-board network must be at least 11.5 volts. If the power supply is too low, this will lead to the fact that it will take much longer to charge the short circuit.
    • Also, the device may fail due to mechanical damage to the insulation. This problem is usually associated with the ingress of engine fluid through worn seals.
    • Poor contact of the product with the vehicle electrical system. In the event that the short circuit case is damaged, this can cause moisture to enter the primary or secondary windings, which in turn can lead to the appearance of a transition resistance.
    • Thermal problems. Some short circuit models are more susceptible to the formation of heat than others, which can also affect their service life.
    • As a result of exposure to engine vibrations, the short circuit performance can also be impaired.

    Checking candles with your own hands

    In accordance with the circuit diagram of motors 405, 406 and 409, spark plugs are used to transfer spark from the switchgear to the engine cylinders. If the operation of the SZ is disrupted, this can affect the quality of the motor as a whole.

    To check devices, you need an assistant:

    • You need to disconnect the high-voltage wire from the first SZ.
    • Using the key, the product is unscrewed from the seat.
    • One end of the device from the electrode side should be brought to the engine or metal on the car body, the distance between the electrode and the mass should be about 1-2 mm.
    • The assistant then turns the starter motor to try to start the engine. If, at the moment of scrolling, a spark has slipped between the electrode and the body, this indicates that the product is operational. Each SZ should be checked in the same way. Please note that problems with the spark supply can also be caused by improper operation of the valve, as well as damage to high-voltage wires.