Chainsaw chain does not stop when idle

Engine fires/sneezes

If you hear popping noises when you work, there is a problem with the muffler or carburetor. How to make a chain saw run quietly? It depends on which component has a defect.

The chainsaw shoots at the carburetor :

  • Too late ignition. the fuel-air mixture doesn’t have time to burn through the cylinder, so you get a sound like a small explosion.
  • Depleted fuel-air mix. There is too little gasoline entering the mixture. adjustment of the chainsaw, or rather the jets, is required to increase the fuel supply. Why the chain saw throttles on its own. for the same reason.

The chainsaw shoots into the muffler :

  • Excessive fuel/air mixture. Reasons why your chain saw fires? The mix contains too much gasoline and not enough air, and as a result the mix doesn’t combust completely in the chamber and partially escapes in the muffler. Fouling on the exhaust is a clear sign. Cleaning the air filter or adjusting the carburetor is necessary.

Chain lubrication system in the chain saw is defective

What are the faults in the chain lubrication system?

In the first case, first inspect the channels that carry oil to the bar, and clean them. Their blockage is quite common.

If there is a big oil leak (a small oil leak is normal in all gasoline-powered saws) you should check the oil pump tubing and fittings for leaks. Tubing can be loose or even cracked. Tubing leaks are repaired by replacing them or sealing material.

As for the oil pumps, then different models of chain saws can be different designs, and the drive is also carried out differently (as a rule, the drive is carried out by a drive sprocket or a special gear on the crankshaft). If the problem is with the oil pump, then most often it is not necessary to completely replace this entire unit, it will be enough to replace its moving part (plunger), it is she most often fails due to ingress of large amounts of dirt and sawdust.

The most serious damage is a crack in the oil pump housing. In this case you will have to replace it completely.

Why chainsaw does not pick up speed?

Almost all systems and components of a chainsaw start up. RPM problems may occur at start-up, the following causes may provoke them:

  • Engine malfunction due to wear and tear or deformation of piston rings and cylinder;
  • Problems with coil or spark plug. no spark igniting fuel mixtures;
  • The carburetor screws are out of balance.

To test the ignition module, proceed as follows

  • The spark plug is unscrewed;
  • Its condition is evaluated. It shouldn’t be flooded with petrol or black residue;
  • The distance between the coil and the magnets is checked (up to 0,2 millimeters);
  • In addition, the spark plug unit can be checked for sparking with a working mains drive.

If the chainsaw still fails to reach the rpm it is worth checking the carburettor. Low and high rpm are set by default and must be re-set after the running-in process and short instrument use.

The rpm are adjusted with the screws and screwed out as far as they will go. In this situation it is necessary to change the setting of the “H” slide valve, which is responsible for the application of the machine at full load. Adjust the fuel mixture while the motor is running at the highest chain speed. A tachometer and the manufacturer’s manual are here to help.

Correct chain adjustment

Your chainsaw depends a great deal on proper adjustment and tensioning of the chain. If the chain is of normal length, this process does not take much time or effort.

Important: Metal expands and becomes hot during operation, which causes the chain to lengthen. Periodically check and correct the tension.

The tightening process is quite simple and takes only a few minutes:

Adjusting the chain to the bar

Important: When tensioned correctly, the chain should run smoothly with light pressure from your hand without making any unusual noise or sticking. At the same time the links should not sag if they are tensioned correctly.

The tensioner design and operating principle

The chain tension is adjusted simply by moving the bar:

The bus is moved by a simple gear mechanism which transmits the force from the adjusting screw to the bus.

There is a spike on the adjustment shaft, which must necessarily fall into the hole on the bar when installing it. This is the meshing that makes the tire move when adjusting.

The screw is located under the hole in the cover that covers the drive sprocket at the side or front, depending on the chainsaw model.

Most models have a slot for a flat-blade screwdriver. Turning it clockwise or counterclockwise moves the tire slowly, millimeter by millimeter per revolution. It makes it possible to achieve the correct tension easily and accurately.

The tensioning mechanism is simple and therefore quite reliable. The only reason it fails is if the drive gear teeth are made of soft or brittle metal. Some unscrupulous manufacturers use parts made of powder metallurgy. The teeth on these gears slip quickly.

In such cases you have to change the whole assembly. You can tighten the chain by hand or with the help of a vise. The bar is clamped neatly in a vice without pressure on the grooves, and the chainsaw is pulled away from the vice until the chain is properly tightened. This is a temporary measure. The chain has to be tightened often, and it’s inconvenient to do without an adjustment mechanism.

Adjustment is carried out with the bar and chain fully in place and the mounting nuts loosened, of which there may be one or two, depending on the model.

Reasons why a chain saw cuts crooked?

There are several common factors that impair the balance of a saw’s cutting set and spoil the cutting line.

  • uneven self-sharpening of the cutting teeth. quite often the chainsaw will saw sideways due to improper sequencing when sharpening the saw organ. According to the instructions, the teeth should be pointed at the same distance. If this rule is violated, the teeth that have been worn down more than the others will wear out more quickly. As a result, the chain is noticeably off-center, leaving behind a crooked sloppy cutting line;

Chainsaw Chain Won’t Stop at idleFIX

  • Operating a chain that does not match the bar. each bar has its own characteristics, including the width of the groove. This is what determines whether the cutter bar can be installed on the guide bar. If you fit a chain with a 1.3 mm pitch to a bar with a 1.3 mm pitch, there is still a 0.2 mm gap. It will lead to uneven movement of the cutting headset on the saw blade, as a result of which the chainsaw will cut crookedly;
  • Increased wear on the chain teeth. if the chainsaw swings to the side. this could indicate excessive wear on the chain. To check the cutter bar, you must remove it from the bar and inspect the plane of its contact with the guide bar. If the cutting teeth are really worn, the chain must be replaced without trying to sharpen it.

The main reason of the chain’s accelerated wear can be irregular lubrication of the chainring. If it is working intermittently, the chain will lubricate in parts. As a result, teeth that are not supplied with oil will heat up more quickly and wear out.

Reasons for premature chain failure

The chain is subject to accelerated lengthening during the running-in phase and in the last quarter of its service life. During these time intervals the headset needs special attention and careful maintenance.

  • The cause of rapid chain stretching can be poor material quality of the budget model, inadequate crowning configuration and excessive wear on the drive sprocket, a faulty or ineffective lubrication system.
  • Complete chainsaw chain performance also depends largely on the condition of the bar and drive sprocket, the quality of the chain oil and the performance of the lubrication system, the timely and proper sharpening of the cutting link edges.

According to professional chain saw operators, it is the operator’s lifestyle and the level of use that influence the durability of the handset. Circuits of the budget group are exposed to a greater extent to tensioning, the more expensive brand-name assortment has no remarks on technical and functional properties.

What you need

To adjust your chainsaw chain tension, you’ll need

  • A socket wrench for the saw cover nuts.
  • Screwdriver or Phillips head screwdriver for the adjusting screw.
  • Tight gloves to check chain tension.

A suitable wrench and screwdriver are usually supplied with the chainsaw. Gloves are needed to protect your hands from sharp chains. You can also check tension with two screwdrivers on opposite sides of the bar for checking.

The chain spins when the chainsaw is started

Chainsaws are going down and that makes them more popular and accessible not only for experts, but also for ordinary, so to say, amateurs. But the all-prevalent dependence. the lower the cost, the less reliable the machine and more often malfunctions occur, for the chainsaw is also vital. But for chain saws of any price range, most of the defects can be really avoided by proper use, care and timely maintenance of machinery. But no one is insured from chainsaw malfunction, as well as any other equipment. Therefore it is suggested to consider the main types of chain saw faults, ways to diagnose, fix and repair them.

All the major faults of chain saws can be divided into two main categories:. the faults of the engine and its various nodes: the system of preparation and fuel supply, ignition, piston group with crankshaft, exhaust system. Faults and breakdowns of other nodes: lubrication system, clutch, chain brake, tire, and others.

Malfunctions of chain saw engine

Here are some of the most common chain saw engine troubles. The main such malfunctions can be summarized as follows:

engine does not start (rather generalized, and the causes may be quite different);

does not develop any power, t.е. it runs correctly at idle speed but stops or freezes under load.

chainsaw, chain, does, stop, idle

Problems with starting the engine

The problem is very important to get the cause of the problem right, because we won’t be able to fix it if it isn’t. There is a chainsaw, almost new, the engine runs fine, but the chain does not saw. Step on it. the engine responds but then tries to stall, t. К. I don’t know how to do it myself.and the chain is tight but the chain is not working. The chain on the bar is not. If there are no extraneous noises when trying to start the chainsaw (knocking, squealing, etc.д. ) very often it turns out that the breakage is not really there. For example if you don’t start your chainsaw correctly and pull the choke for a long time, the engine just floods and it’s very hard to start it.

In order to properly start a cold chainsaw engine, set the lever or switch to the choke closed position. Then you need to pump the mixture into the carburetor if you have a fuel pump. Pull the starter grip until you feel resistance from the engine and pull vigorously to the side. After two. After three of these steps, the engine should start and then stop. If it does not happen you should set the lever to the half throttle position or just to the work position and then go on starting the chainsaw in this mode. Many chain saws have an automatic “half throttle” lock when the choke is pulled. Some models have an ignition key switch, it is important to make sure that it is on.

If the engine won’t start, the first thing to do is to unscrew and inspect the spark plug. The chain should not move when idling; the chainsaw will lose power or it won’t. There are cases, when starting in cold weather, flood the combustion chamber with fuel. Then also unscrew the spark plug, dry the combustion chamber with idle power, clean the spark plug, unscrew it and restart. If the chainsaw does not pump does not work, the chain does not rotate as a result. It is a good idea to check for spark plugs right away. put the cap on the unscrewed spark plug with high-voltage wire, put it on the cylinder and yank the starter. Visually observe frequent blue spark. Good. Screw the spark plug back in and start the engine. If there is no spark, change the spark plug and try again. Not again. check the connection of the high-voltage wire to the spark plug, the coil and the ignition system.

READ Chain sharpening tool for chainsaws

Generally speaking, the condition of the spark plug is a good indicator of the type of fault.

  • Dry. Most likely, no fuel mixture enters the cylinder. It’s not the ignition system, so screw the spark plug back in and check the fuel system.
  • Wet, heavily spattered with fuel. The cause of excessive fuel mixture lies either in improper starting rules, as described above, or in improper adjustment of the carburetor.
  • The plug is covered with black soot. This could indicate the use of low-quality oil, an improperly adjusted carburetor, or an improperly calculated gasoline to oil ratio. The spark plug should be washed, cleaned of sludge with a sharp object (an awl or a needle), wiped with an abrasive cloth over the electrodes and replaced.

Checking the spark plug, pay attention to the gap between the electrodes: the normal value is between 0.5 and 0.65 mm. Damaged or worn gasket should be replaced.

Checking and Adjusting a Chainsaw Carburetor

A properly adjusted chainsaw carburetor ensures that the chainsaw operates efficiently at full power with the most economical fuel consumption.

The need to adjust the carburetor of a chainsaw does not arise often, as the adjustment is initially carried out by the manufacturer to achieve the optimal mode of operation. Adjustment screws are used to fine tune the carburetor on the chainsaw if necessary.

When and why does this need to happen??

Among the reasons for the failure to fix the adjusting screws, the most common are the following:

  • Severe vibration or damage to the safety cover. It is rare, but it does happen.
  • Severe engine (piston) wear and tear. Of course, in this case you should take more care of the repair of the chainsaw engine, but still adjusting the carburetor can improve its functionality for a while.
  • Clogging in the carburetor due to a damaged air filter, poor gasoline quality, or scale buildup. In this case, in addition to the adjustment of the carburetor, you cannot avoid its flushing.

The chain on the chainsaw/brake does not turn / consequences

Taking apart the consequences of using a chainsaw

with brake on. And general recommendations for taking care of a benzo.

The chain at the chain saw jammed chain, looking for the cause.1 part.

Remove the sprocket and check the condition of the oil pump.

What are the signs that a chainsaw carburetor needs adjustment?

  • First, the engine won’t start or will start but then shuts down. This is most often caused by a depletion of the fuel mixture.
  • Second, there is a significant increase in fuel consumption and emissions. Increased exhaust emission indicates that the fuel does not burn completely, which could be due to an oversaturation of the fuel mixture.

The scheme for adjusting the carburetor of a chainsaw can vary slightly depending on the manufacturer (the process of adjusting the carburetor of a specific make and model of a chainsaw is described in detail in the instruction manual), but the general principles remain the same for all brands. The purpose of adjusting the saw is to change the quantity and quality (enrichment) of the fuel mixture flowing into the engine cylinder.

READ How a Chainsaw Chain Brake Works

To learn how to adjust the carburetor on a chainsaw, you should learn to distinguish three screws (some models have only one).

Screws L and H are only similar in appearance; in fact, they are different

Each screw has its own letter designation:

  • “L” serves to set the low rpm;
  • “H” is needed to adjust the upper rpm;
  • “T” is needed to adjust the idle speed (models with only one screw have only it).

There are mandatory safety requirements that must be followed when adjusting the carburetor of any chainsaw:

  • Make sure the chain is pointing in the opposite direction from you.
  • The saw must be positioned firmly on level ground and the cutting head must not be in contact with any object.

Please note: the exact values for the angle of rotation of the adjusting screws can be found in your chain saw Instruction Manual. Following the manufacturer’s instructions precisely will help you avoid damaging the engine.

The carburetor adjustment process consists of two steps: basic (engine off) and final (running warm engine).

Basic chain saw carburetor adjustment

Slowly turn the maximum and minimum adjusting screws (H and L) clockwise as far as they will go and then turn them counterclockwise about 1.5 turns.

Idle speed adjustment

Before this stage of adjustment, it is necessary to warm the engine up for 5-10 minutes avoiding high RPM.

Turn the idle speed adjustment screw (T/LA/S) counterclockwise to obtain the minimum RPM at which stable engine operation is assured. Check that the chain is not moving. But not more than 1/8 of a turn. But on the package is not difficult to pick up a new chain is lubricated. The chain does not turn; and when your chainsaw is not running. That is, if the engine idles, turn the idle speed screw clockwise. If the chain is driven, turn the screw counterclockwise.

To complete the carburetor adjustment on your chainsaw, check the engine for acceleration and maximum rpm.

Checking acceleration

To check engine acceleration, smoothly press the gas pedal and make sure the engine is going from idle to maximum RPM (2,800 to 11,500 to 1,500 RPM, depending on make and model) quickly. But even such a technique with a chain saw only works on the chain saw does not. If the engine revs slowly, turn the L screw counterclockwise (not more than 1/8 turn).

Adjusting maximum RPM

To adjust the maximum rpm use the H. RPM increases when it is turned clockwise and decreases when it is turned counterclockwise.

The maximum rpm for chainsaw engines ranges from 11500 to 15000 rpm. Higher speeds can be dangerous to the engine and are simply not provided by the ignition. The maximum RPM can therefore be determined by the occurrence of an ignition interruption. In case they occur, turn the screw H slightly anticlockwise.

Re-check at idle speed

After you have adjusted acceleration and maximum engine speed, be sure to re-check the chain saw’s idle speed. If the carburetor is properly adjusted, the following conditions must be met:

  • The chain should not move when idling;
  • The engine has to be able to rev up quickly;
  • the operation of the engine should resemble a four-stroke engine.

If the work of the chainsaw does not meet at least one of these conditions, the adjustment procedure (with the exception of the basic step) will have to be repeated again.


You also need to check the muffler. If it is demountable, disassemble and examine it, remove all the soot. In some models of chainsaws muffler will have to twist, otherwise you can not check. Muffler that cannot be disassembled can be dried with a hair dryer after washing. Remember that soot contains substances that are carcinogens, and dry cleaning, which can lead to their inhalation, is unacceptable. When removing the muffler, the exhaust port of the engine is plugged with a clean rag. The chain spins when the chainsaw is running at idle speed, and at rpm. Do not underestimate this failure. If the muffler gets clogged, the chain saw will lose power or won’t start at all. One of the reasons the muffler can get clogged. is the use of fuel mixture with too much oil (more oil than the manufacturer recommends), and the use of either oil that is not intended for two-stroke engines or low-quality oil.

Chain lubrication system

Faults in the chain lubrication system are seldom in a chain saw repair manual and are quite common. They usually show up as a lack of or inadequate supply of lubricant to the chain and as oil leaks. If the chain is dry, the first thing to do is to inspect and clean the oil channels that feed oil into the bar. If they get blocked. are not uncommon.

If there is a significant (small is considered normal) leak of oil, you need to check the tightness of the connection pipes to the pump fittings. STIHL chain saw works, but chain won’t turn when you apply gas. These can be loose or cracked. A leaking oil system can result in underlubrication of the chain in addition to dripping. Pump begins to suck air, which affects its performance. A leak is eliminated by replacing the tubes or sealing them with sealant.

chainsaw, chain, does, stop, idle

The oil pumps are of different constructions and can be driven in different ways. If the chainsaw does not start, but the spark plug works if the engine idles. very often it is not necessary to change the whole oil pump, it is enough to change its moving part called plunger, often it fails due to large amounts of dirt and sawdust, it just clogs and its edges get stuck. The oil pump is usually driven by a sprocket or a special gear on the crankshaft.

The most serious breakdown of the lubrication system are cracks in the oil pump housing. In this case, it must be replaced.

Chain brake

The chain brake does not work if the cover and brake band are dirty with sawdust or grease. This is also caused by belt wear. In the first case, you need to clean the underbody, in the second. Replace the brake band.

If you have a lawn mower in your household. use, maintenance and repair. Useful for you. over, from a chainsaw you can make a lawn mower yourself, thus unifying the tool.

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