How to set the ignition on the trimmer

Ignition adjustment procedure

Setting up the ignition system is simple and identical on different trimmer models, be it 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 stage may differ on different brushcutter models (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.

ignition, 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 optimum 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 ignition is on on the brushcutter. You can learn more about the process of adjusting the trimmer ignition system on the Internet, where many videos on this topic are available.

How to set the ignition on the trim tab

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 arranged 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.

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 grass trimmer will not start. Later, after cooling down, the coil returns to the working level, the single-axle tractor turns on and runs idle or under load for some time until the magneto temperature 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.

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 nearly reaches dead center from above, 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 shifted 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.

Typically, the flywheel with magnets is set in an ideal position, precisely coordinated with the piston operation, 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.

The first way

You can check the performance of the magneto using a tester. To do this, you must 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 kohms, depending on the model of the grass trimmer, 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.

Features of adjustment on different models of trimmers

The ignition system works in a similar way on different brands of equipment, so the process of adjusting it 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 grass trimmer for a particular model are usually shown in the instruction manual of the tool.

So, you can do the ignition adjustment for a gasoline grass 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 starting of the brushcutter engine. 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.

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.

Trimmer ignition setting

On gasoline trimmers, both two-stroke internal combustion engines (ICE) and four-stroke engines are used. 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.

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. Also on one side of the flywheel are permanent magnets, 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.

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.

How to set ignition coil gap on your gas trimmer or blower!

  • 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 kOhm 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.

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 grass 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.

Why do I need ignition adjustment

In some cases, when the engine does not start, the ignition will need to be adjusted. 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 original position), the fuel ignites before the piston passes TDC, then it goes back, and the crankshaft rotates in the opposite direction. This movement can damage the starter assembly, cut the starter cord, etc. In this case, early ignition of the fuel occurs.

There may also be a late ignition on the trim: the piston, after 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.

Как выставить зажигание и зазор на триммере своими руками.How to set the ignition on the trimmer.

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.

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 petrol cutter, 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 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 adjust 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 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 ignition on the trimmer will be adjusted.
  • Recommendations for the use of gasoline-powered tools

    Before the first use Before the first use, it is recommended to un-preserve the gasoline-powered tool:

    • unscrew the candle
    • we collect a little oil into the syringe (about 4-5 drops)
    • dripping into the cylinder, trying to hit the cylinder walls.
    • without twisting the spark plug, pull the starter handle 2-3 times to lubricate the cylinder itself.
    • check the spark plug gap, which should correspond to about 0.7-1 mm
    • twirl the candle in place

    We recommend using such operations also in case of long-term storage of the gasoline-powered tool (2 or more months) Put oil under the spark plug and lubricate the cylinder before and after storage. As a result of this procedure, the engine will be slightly more difficult to start, however, this will significantly extend the life of the engine.

    To start a cold engine of a gasoline-powered tool, you must:

    • pump gasoline 3-5 times with a rubber button (located under the carburetor) so that the gasoline gets directly into the carburetor itself
    • check the grass trimmer power button on the grass trimmer handle, it must be in position “1” or “start”.
    • pump fuel with the gas button located on the right handle (about 2-4 times). Do not overdo it by pumping fuel, it can flood the candle.
    • set the handle (“suction”) to the suction position,
    • as soon as the grass trimmer starts up, the choke handle must be pushed back as the grass trimmer should not and will not work normally in the suction position

    It is forbidden to turn off petrol equipment at high speeds. This can damage the ignition coil.

    Oil Since the Ukrainian market is filled with counterfeit oil, we strongly recommend that you use certified oil under the Sturm brand! 2t, the quality of which is confirmed by certificates and it really has the necessary characteristics for the durable operation of gasoline equipment.

    A mixture of oil and gasoline. Adhere to the proportions indicated on the oil packaging. Don’t mix too much tool mix. The finished mixture should be stored for no more than 2 weeks. With prolonged storage, the mixture begins to oxidize, which negatively affects the operation of the engine.

    Line selection. All Sturm brushcutters! Energomash, SOYUZ, BauMaster are equipped with a line with a diameter of 2.4 mm, round. In practice, the ideal diameter is 2.7 mm, which we also stock. To install a fishing line with a diameter of 3 mm, we recommend slightly reaming the ears on the inside of the reel with a 3-3.3 mm drill.

    Line winding Pay attention to the correct winding of the line in the spool. The arrows on the coil body will point you in the right direction. The line should not cross and get tangled when winding. It is recommended to use about 3-4 meters of line per winding.

    Maintenance of the gas powered tool Perform regular maintenance of the gas powered tool. Service includes visual inspection, cleaning and replacing the air filter, spark plugs, and checking for grease in the grass trimmer lower gear.

    During work. Do not use the trimmer at high rpm for a long time. Gas powered tools, like any gasoline engine, do not like high revs, since this is critical for the engine. Ideal load should be slightly above average engine speed. Do not overheat the engine. Optimal work ratio. 20 minutes of work / 5 minutes of break.