Chainsaw spark plug gap: is it dangerous and how to put everything back in place - Setafi

Novice chainsaw users often ask the question: “How to check the ignition on a chainsaw?” Without much explanation. Why they do this and what they want to do with further information is not clear.

The ignition of a chainsaw is a complex system, and the wrong gap can lead to deformation of the entire device. If your saw does not start, then the ignition system is immediately checked. And our short article will tell you how to check the ignition coil on a chainsaw. Get comfortable, we're getting started!

The design of the chainsaw ignition circuit: what parts does it consist of

Before diagnosing, servicing or fully repairing the entire chainsaw mechanism, you need to know what to repair and look at. In our article, we will deal with only a small element - checking the ignition coil of a chainsaw. Consider what parts the system consists of:

• Magneto for a chainsaw (in simpler terms, a coil) is the main component of the system from which an electrical impulse comes.
• The flywheel is an aluminum part with magnetic soldering. Possibly sprayed. Generates the spark itself by acting on the ignition coil. Also, in addition to creating a spark for starting the engine, the flywheel cools the system and increases the strength of another part - the crankshaft.
• High voltage wire. It is also called an armor cable. This is a kind of wire with good insulating windings. Transmits impulse from coil to spark plug.
• The spark plug is the last element in the ignition system. It consists of two parts: the first half is located in the internal combustion engine, and the second is outside (the high-voltage wire is powered to it). The candle is tightly twisted into a special hole, completely isolated from the motor housing. With the help of a candle, the necessary spark is formed, which ignites the fuel in the combustion chamber.
• Starter (starting device) - an auxiliary element for working with the contacts of the ignition coil. Allows you to control the engine and stop it in time when the work is completed.

The chainsaw's ignition system acts like a conventional generator. A flywheel rotates with magnets tuned to different poles. They create an electromagnetic field, which is then converted into a current charge.

The coil "excites" the electric current, passing the impulse to the transformer. Then it is converted to high voltage and fed to the spark plug. And already there a spark appears, igniting the fuel in the engine chamber. The chainsaw starts up.

What affects the gap on the chainsaw candle

Gasoline internal combustion engines have an ignition that does not work if one of the structural elements fails. Whatever one may say, without the slightest detail, the engine will not start. It's not like with a TV: slammed on the lid, and everything worked.

Even a small misfire or breakdown in a well-established system can cause a unit to malfunction. The slightest soot on a candle as an example.

If the gap of the ignition coil is found to be within normal limits and there are strong electrodes in the chainsaw, nothing may happen. But sometimes this is not enough to break through the dense mixture of the atmosphere at a long uncharacteristic distance.

Also, a greater than necessary distance increases the energy output of the coil, reducing the ignition of the spark. The working mixture does not ignite when the starter is moving. The result - the engine either does not gain momentum, or does not start at all. Next, we will talk about what gap on the chainsaw spark plug is normal and how to fix the situation if you have them incorrectly set on the saw.

How to check the spark on a chainsaw and set it to the required value

Loads on a running engine constantly negatively affect the degree of fixation of all elements. There's nothing you can do about it. Therefore, from time to time diagnostics of the device is necessary.

One of the first problems of a rare chainsaw diagnostic is a misalignment of the ignition system, which requires the correct gap between the ignition coil and the chainsaw flywheel.

The average value that must be maintained between the coil and the flywheel is up to 0.4 mm. The exact parameters are always indicated in the instructions or data sheet of the tool. If there is no specific data, then put somewhere 0.3 mm - you can't go wrong.

To set the correct value, we need several tools:

• Screwdriver with a set of nozzles (bits).
• Paper spacer - with it we will adjust the working gap.
• Thread lock. If not, it's not critical. It will work without it for the first time, but then you will have to configure the system more often than usual.

First we need to remove the left side of the case. Under it are all the elements of the ignition.

Loosen the coil screws with a screwdriver. It is better if you unscrew them altogether and fill the threaded lock into the holes. Then not a single screw is accidentally unscrewed and lost.

Install a paper spacer between the flywheel and the module. It can even be cigarette paper or a piece of plastic bottle.

We unfold the flywheel with magnets so that they touch the coil contacts. There is already a spacer there. The effect of magnetizing the element should be created. Then we tighten the screws back, a little stronger than the average (do not twist, so as not to disrupt the threaded connections).

Remove the spacer and see how the flywheel moves. It should not come into contact with the coil, it should spin smoothly.

That's all. It remains only to find out how to check the coil on a chainsaw. If it is working, then the spark appears already at the first movement of the starter. Let's see how it works in practice.

How to check the magneto and spark plug on chainsaws

It happens that the problem itself does not come to light. Or you have already done all the work and want to experience the result before pouring fuel into the chainsaw and directly work. So, we check the ignition coil of the chainsaw. Here are some test steps:

Measuring resistance with a multimeter. To perform the procedure correctly, you need to know the standard parameter for your tool - it is in the instructions or in the data sheet.

Due to the use of semiconductor parts in the system, the circuit ringing system may indicate an open circuit. Don't worry, everything is fine. If the candle is faulty, the multitool will have a positive result (the coil did not give resistance).

You can also check the spark with a special device. Such a device is placed to break the circuit. It is located between the wire and the spark plug. Test indicators are displayed on the scoreboard. The device is situational, and you are unlikely to find it in the store. But in service centers and service stations there is a lot of such material. You can ask a friend to check the candle for serviceability.

Make your own ignition. To do this, the candle is turned out and the body is placed against the cylinder. Next, pull on the starter. If a spark appears, at least minimal, everything works. But if there is a drawback in the example, the flywheel spins faster and the results may be distorted. This is because the candle during the test is incorrect.

If the above options did not give any results, or there is no tool at hand at all, then try doing this:

• Remove the cap from the candle and insert a nail or wire up to 1 cm from the cylinder. Carry out the operation very carefully so as not to damage the parts.
• Start the tool and see if there is a spark while the starter is running. If everything works well, then the spark is strong and bright blue.

This method is the last resort. It is very dangerous, so you need to follow a few rules:

• You cannot completely remove the candle. So the flywheel will move faster, and this is an abnormal mode of operation of the motor - you will not get the correct result.
• A parameter of 1 cm is an average. It is necessary to place the metal element at the optimal compression distance and the characteristics of the fuel mixture. For more information about this, see the instructions for the device.

It happens that the chainsaw does not start due to a lack of spark on the electrodes themselves. Although less common, such an option exists.

How to check here? It's simple: we turn out the candle and put an armored wire on it. We try to ensure the most reliable contact of the ignition housing with the cylinder. After we pull the starter - we start the engine.

In this case, the spark should be clearly visible. If there is gasoline in the tank, but the spark has not arrived, somewhere in the system there is a break or a part malfunction. Check the magneto for continuity.

After all the procedures, the engine should work. If you have any questions or suggestions - ask in the comments under this article. And that's all for today! See you!