A situation where after winter downtime or in the midst of grass mowing gas-pots won't start, and when scrolling with the starter there is no spark, familiar to many owners of garden equipment. This is a classic symptom indicating that the fuel-air mixture in the cylinder does not ignite due to a failure in the ignition system. Unlike fuel supply problems, the lack of an electric spark often baffles beginners who start to sin on the carburetor or gasoline quality, although the root of the problem lies in the electrician.
To successfully restore the tool, several key nodes must be consistently checked. Most often, the culprits are a spark plug, a polluted coil or a broken gap between the magnetic conductor and the ignition module. Understanding the principle of operation of the system allows you to quickly localize the malfunction and avoid buying unnecessary spare parts. Stihl, Husqvarna, Champion Chinese analogues have a similar design, so the diagnostic algorithm will be universal.
Before disassembling half of the engine, make sure you use a working candle and a quality fuel mixture. Often, the lack of a spark is just the tip of the iceberg, behind which lies a more serious problem, for example, a breakdown of a high-voltage wire or a failure of an electronic module. In this article, we will discuss each stage of the test in detail so that you can get your trimmer back into operation as quickly as possible and without unnecessary costs.
Primary diagnosis and check of spark plug
The first and most obvious step in finding the reason why gas-pots won't startIt is a visual inspection and check of the candle. To do this, you need to remove the high-voltage cap and twist the candle with a special key. Pay attention to the state of the electrode: if it is black, wet from gasoline or covered with carbon, this may indicate a violation of the combustion process or re-enriched mixture.
Check spark is best carried out by wearing the cap back on the twisted candle and pressing it with metal threads to the engine body (mass). With a sharp jig of the starter should skip a bright blue-white spark. If the spark is not at all or it is a weak, reddish hue, the problem lies in the current generation system. It is important not to hold a candle during the test to avoid electric shock, although the tension there is not fatal, but unpleasant.
- 🔌 Check the density of the high-voltage cap planting on the candle – oxidation of the contacts often breaks the chain.
- 💧 Inspect candle carvings: Having oil or a large amount of sodium requires replacing the part or cleaning thoroughly.
- ⚡ Test the spark only for the "mass" (metal part of the engine) to avoid damage to the electronic module.
If the candle is dry and there is no spark, try to replace it with a new one that is known to work. This is the quickest way to eliminate the problem with the candle itself.
In some cases, the problem may not be in the candle itself, but in the high-voltage wire. If the wire is cracked, rubbed or has traces of breakdown (black dots on the insulation), the current will go to the side, without reaching the electrode. Replace the wire or isolate the damaged area if possible. It is also worth checking the integrity of the spring inside the cap, which provides contact with the candle.
Failures of the ignition coil and module
If the candle is all right, the next candidate for the test is ignition (magneto) Modern benzokos use electronic ignition, where the coil and the breaker are combined into a single module. The failure of this node is a common reason for the absence of a spark. The coil may overheat, get mechanical damage or simply develop its life.
One of the most common problems is the violation of the gap between the flywheel magnetic conductor and the ignition coil. Over time, the fasteners may weaken and the gap will increase, causing the magnetic field to become too weak to generate a spark. The normal clearance is usually from 0.2 to 0.4 mm (approximately the thickness of a business card or piece of paper). To adjust, the screws of the coil attachment are weakened, a calibration pattern is applied and the module is attracted to the flywheel magnets.
⚠️ Warning: Never test for a spark to burst while holding the wire on weight. This creates too high a resistance and can break through the insulation inside the coil, permanently disabling it.
Check the serviceability of the coil can be using a multimeter, measuring the resistance of the primary and secondary windings. However, the exact values depend on the trimmer model, so it is easier to use the exclusion method. If the candle is new, the gap is set correctly, and the spark is not - most likely, the module needs to be replaced. When installing a new module, be sure to follow the technology of setting the gap.
| Symptoms. | Possible cause | Elimination method |
|---|---|---|
| There's a spark, but it's weak. | Candle contamination, small gap | Cleaning or replacing candles, adjustment |
| There is only a spark in the cold | Failure of the module during heating | Replacement of the ignition coil |
| No spark at all. | Chain break, module burnt | Chain vertebrae, module replacement |
| Spark unstable | Poor mass contact | Contact sweep, screw lift. |
Problems with grounding and stop button
Often, owners are looking for complex reasons why. gas-pots won't startAnd forgetting the simplest thing, the grounding circuit. In the ignition system of the gas pump, the spark disappears when the chain is closed to the mass through the Stop button. If the wire going from the coil to the button, rubbed and touches the engine body, the spark will constantly go to the "ground", bypassing the candle.
To diagnose this malfunction, it is enough to disconnect the wire going from the ignition module to the engine stop button. After disconnecting the wire, try to start the trimmer. If the spark appeared and the engine started (don’t forget to turn it off again, since the stop button will not work), then the problem is found. The wire may be clamped, rubbed or oxidized at the contact point.
- 🛑 Examine the wiring for mechanical damage and melting.
- 🔋 Check the Stop button for sticking or shorting inside the housing.
- 🔧 Make sure that the screws of the coil attachment do not close the contacts of the module to the body.
Another reason for the closure of the mass can be poor-quality repair or intervention in the design. For example, if during the replacement of the ossicles or cleaning of the carburetor, the insulating layer of the wires was accidentally damaged. In such cases, careful isolation of damaged areas or complete replacement of the wire harness helps.
How to temporarily get a braid if the stop button burns?
If the stop button fails and closes to the mass, you can disconnect the wire from the module and isolate it. Start and jam the tool will have to by blocking the piston through the candle hole (inserting the cord into the cylinder), but this is a temporary solution before buying a new button.
Effect of the state of the engine on spark formation
Do not forget that the ignition system is closely related to the mechanical state of the engine. If the crankshaft has a backlash or a swerved obular, this can cause the flywheel with magnets to shift. As a result, the moment of passage of the magnet past the coil changes, and the spark either becomes too weak or disappears altogether. Also, with strong wear of crankshaft bearings, compression may be broken, which indirectly affects the quality of spark formation.
Damage to the flywheel veneer is another hidden cause of problems. If the veneer is cut or deformed, the flywheel is shifted relative to the crankshaft. This leads to the fact that the spark skips not at the moment when the piston is at the upper dead point, but with a delay or advance. The engine in this case may not start at all or shoot at the muffler.
To check, you need to remove the flywheel (using a special remover so as not to damage the shaft) and inspect the veneer groove. If you see signs of twisting or deformation, the veneer must be replaced. It is also worth checking the condition of the crankshaft cone under the flywheel - it should be clean and without bullies.
⚠️ Note: When removing the flywheel, do not use a hammer to strike the shaft or the flywheel itself. This can lead to the destruction of crankshaft bearings and expensive repairs.
Specificity of diagnostics for different brands
Although the principle of operation of two-stroke engines is the same, different manufacturers bring their design features. For example, in trimmers. Stihl and Husqvarna Modular ignition is often used, where the coil is built into the housing or has a specific attachment. In Chinese models (in Chinese models)Champion, Patriot) individual coils are more common, which are easier to replace but are more sensitive to assembly quality and vibration.
In some professional-grade models, the ignition system may have additional overheating protection or electronic advance angle control. If this technique is not started, simply replacing a candle may not help. A deeper diagnosis is required using an oscilloscope or specialized testers, although in practice, banal dampness or contamination is most often to blame.
☑️ Diagnostics of lack of spark
It is also important to consider operating conditions. If you work in damp weather or mow dew, moisture can get into a candle well. Water is an excellent conductor and shortens the spark. In such cases, it is enough to dry the candle well with compressed air or simply let the tool stand in a warm place.
Prevention and care of the ignition system
To ask why gas-pots won't start"not caught you off guard in the high season, you need to regularly maintain the ignition system. Prevention takes a minimum of time, but significantly prolongs the life of the tool. First of all, this is the content of the tool in cleanliness: grass and dust stuffed under the skin of the starter can contain moisture and cause corrosion of contacts.
Once a season, it is recommended to remove the candle, clean it from soot and check the gap. It is also worth blowing the area around the cylinder and coil with compressed air. If you plan to store for a long time (for example, for the winter), it is better to twist the candle, drop a little engine oil into the cylinder, turn the starter several times and twist the candle back. This will protect the cylinder from corrosion and preserve the elasticity of the glands.
- 🧹 Regularly clean the cylinder ribs and coil area of dust and grass.
- 🛢️ Use quality oil for two-stroke engines in the right proportion.
- 🔦 Keep the tool in a dry room, protected from temperature changes.
Compliance with these simple rules will avoid most launch problems. Remember that a high-quality fuel mixture is the key not only to clean engine operation, but also to preserve the properties of the spark plug. Nagar from bad gasoline is one of the main reasons for the disappearance of the spark.
90% of problems with lack of spark are solved by replacing the candle, cleaning the contacts or adjusting the gap of the coil. Don’t be in a hurry to change an expensive module without carefully checking the simple elements.
Can I use a car candle in a gas tank?
It's not recommended. Candles for two-stroke engines (benzokos, saw) and four-stroke (cars) have different characteristics of the kalyl number and design. A car candle can not give a spark at low speeds or, conversely, overheat and cause a kalyl ignition, which will lead to the destruction of the piston group.
What to do if the new candle turns black?
If a new candle is quickly covered with black soda, it indicates a re-enriched fuel mixture (a lot of oil in gasoline) or problems with the carburetor. Also, the cause may be poor fuel quality or a violation of the engine thermal regime (clogged cooling ribs).
How often should I change the candle in the trimmer?
The candle’s resource depends on the quality of the fuel and the intensity of the work. On average, the candle is recommended to be changed once a season or after 100 hours. However, if you have problems with the start or loss of power, the check should be carried out earlier.
Why is there a spark, but the gas pump still doesn't start?
The presence of a spark does not guarantee a launch. The engine also needs proper compression and a high-quality fuel-air mixture. Check if the gasoline is coming into the cylinder (the candle should be wet after starting attempts), and if the muffler is not filled with soda.