Chainsaw chain does not stop at idle

Chain lubrication problems

For proper operation, the chain must be constantly lubricated in order to reduce friction between the tire and the links, as well as to prevent premature wear of the links.

• If the chain is not lubricated on the chainsaw, then there is a problem with the oil pump. oil is not supplied due to a clogged channel. Lack of lubrication is the reason why the chain stretches or why the chain breaks. Clean the channels, the smallest particles of shavings constantly get there and clog them. May also cut off the oil hose. If you need to adjust the oil pump of the chainsaw or repair it, it is better to contact the service.
• Splashes oil from the chain. Incorrectly selected lubricant. it is too liquid, therefore it does not so much lubricate the links as splashes on the wood. Replaces grease with a thicker one.

Not gaining momentum

The problem manifests itself at startup. The chainsaw does not develop speed, it works in jerks or idle, stalls, starts from the pusher, when starting it beats back.

• If the device does not keep idling, the reasons may be a clogged filter, poor-quality combustible mixture, carburetor, ignition module, or deformation of engine elements under load.
• If the saw is not producing full power, check the carburetor. There is a possibility that the settings of the worker node are set incorrectly. Adjust the “H” jumper, which is responsible for cutting under load. To do this, adjust the fuel delivery at high speed.
• Does not slow down. The problem is that the device can quickly develop speed at high revs and not drop it. It is necessary to check the functioning of the throttle valve, switching the toggle switch, the presence of a corkscrew on the throttle shaft.
• Accelerates rotation speed uncontrollably. Causes may be in the carburetor, fuel delivery system, connectors leading to the carburetor.
• The technique works only on suction. The reason is improper preparation of the fuel mixture, a large amount of oil.

These are the main, most common causes of this type of malfunction.

The chain does not rotate

Why the chainsaw chain does not rotate when the engine is running even at full speed?

• Leading asterisk. Either it is jammed, or the crown is worn out so much that it does not engage and the chain does not spin on the chainsaw. In any case, it is necessary to disassemble the sprocket in order to find out the exact reason why the chain does not spin. If the crown is worn out, it is necessary to replace the sprocket (or the crown itself, if the sprocket has a prefabricated structure).
• The chain brake is jammed. As a result, the sprocket is blocked by the brake mechanism, while the motor runs. Stop the engine and release the brake. If this happened under load, the brake mechanism will have to be changed, as well as the sprocket, because due to the high temperature, many elements can melt and overheat.

Stalls at maximum speed and works only on suction

• Clogged air or fuel filter. Seals need to be cleaned and checked.
• The breather is clogged and because of this, fuel does not flow and the pumping of gasoline on the chainsaw does not work. Take the needle and gently clean the breather.
• Fuel pump malfunction. Remove the pump and check if gasoline is oozing out of it. If oozing. replace the gasket or the pump itself.

The main malfunctions of the chainsaw: causes

Every year, manufacturers are developing equipment that is more complex and more reliable in design, but simple to operate. Chainsaws are no exception. But whatever modern functions are included in the device, it is difficult to avoid a chainsaw malfunction. Diagnostics of breakdowns can be carried out independently, using the instruction manual. Consider the main types of faults encountered.

DIY chainsaw malfunctions

Even professional chainsaws from world famous manufacturers break down. no one is immune from this. The question is how often breakdowns occur and how serious they are. It is one thing when you need to sharpen the chain or replace the drive sprocket, and another thing if the chainsaw does not start or fires at the carburetor. In fact, most of the faults can be easily eliminated with your own hands, for example, when the chainsaw does not lubricate the chain or stalls.

How to diagnose faults and repair a chainsaw with your own hands

A chainsaw in the country, in a private house is not uncommon. She can be amateur, semi-professional and professional. The choice depends on the frequency and complexity of the activity. It greatly simplifies the work of harvesting firewood, helps to quickly put the log house. In the event of a breakdown, in most cases, it is possible to repair the chainsaw with your own hands. Equipment failure may be due to idle problems, the mechanism will not start or troit.

The principle of repair for all chainsaws is approximately the same. Before work, be sure to read the instructions. For this type of equipment, it is not the repair itself that is of great difficulty, but the search for the source of failure.

Why does the chain fly off?

Why does it break off, or why it gets stuck during prolonged work with a chainsaw. There may be several reasons why the chain breaks, but the most common of them is mechanical damage to the tire on which the saw element of the tool is held.

We deal with typical chainsaw breakdowns

Why clamps the chain on a chainsaw?

The reason for this also lies in the deformation of the tire. If, as a result of the impact, it was compressed, then, accordingly, the teeth of the chain will be locked inside the groove of the bar. Also, the reason that the chain does not spin is a breakdown of the adjusting bolt, which is used when installing a new saw element. In order to understand exactly why the chain does not rotate, it is necessary to dismantle the tire and carefully inspect the internal structure of the chainsaw for debris inside it. You will also need to inspect the instrument air filter for clogging.

Replacement of wearing parts

Some parts of the chainsaw that are subject to natural wear and tear must be replaced after a certain period of use. Their failure is not considered a malfunction. Wearing parts include a chain, a bar, a drive sprocket, elements of an anti-vibration system and some others.

If you do not replace wearing parts in time, their excessive wear will adversely affect the rest of the chainsaw. In particular, if the tire and drive sprocket are not changed in time, the increased vibration will adversely affect the crankshaft bearings. The maximum depth of the sprocket teeth must be 0.5 mm. In practice, sprockets are often operated to a wear depth of 1 mm or more, unaware that this leads to an increased load on the crankshaft bearings and their accelerated failure. When 3-4 chains are worn, it is necessary to change the tire itself, by which time its wear reaches its limit values.

Chainsaw bar wears especially in the area that is cut most frequently, usually the underside of the guide bar. For even wear, with each chain change, the bar must be turned 180 ° relative to the horizontal axis.

When installing a new chain, install a new drive sprocket. Since the life of the drive sprocket is twice the life of the chain under normal load, it is advisable to use one sprocket for alternating operation of the two chains. This allows the sprocket and chains to wear out almost at the same time. If a new chain is placed on a worn sprocket, the drive links of the chain wear out much faster. To operate your chainsaw economically, always use together: one guide bar, two chain sprockets, four saw chains.

Modern chainsaws delight us with their reliability, ease of operation and the presence of many special vibration suppression systems, automatic chain lubrication, and easy starting. But even such equipment fails over time, especially if it is not serviced on time and correctly. We offer to study the characteristic breakdowns of chainsaws and methods of eliminating them with your own hands.

Signs of breakdown and self-repair of the chainsaw motor

One of the most frequent breakdowns of every chainsaw is a malfunction of its motor. It is quite simple to determine that the reason lies precisely in this. Several signs may indicate this problem:

• The chainsaw does not start;
• The instrument motor is unstable and very noisy;
• The engine manages to start, but it constantly stalls;
• The motor overheats very quickly;
• The chainsaw only works on suction;
• The motor smokes a lot, but the power, at the same time, decreases.

If you do not know how to make the chainsaw work quietly, then, first of all, you will need to study its design. Only then can you begin to repair the tool yourself.

To avoid such errors, you should once again study the procedure for starting a chainsaw with a cold engine. The algorithm of actions is as follows:

• Lower the throttle switch to the “CLOSED” position;
• Press the carburetor fuel priming primer several times;
• Pull the starter handle until resistance appears;
• After the saw starts and immediately stalls, move the choke lever to the “Open” position;
• Start the chainsaw again and let it idle a little.

If this does not help, then you will need to inspect the spark plug. If you see a large amount of oil on it, then the part needs to be unscrewed and dried. After that, you will need to dry the combustion chamber, screw in the candle and try to start the saw again.

The serviceability of the candle itself can be checked as follows. First, you need to connect a high-voltage wire to it, put the spare part on the cylinder and pull out the starter cable. In this case, in no case grab the candle with your hands. If you notice a blue spark, then the candle is completely functional. Screw the part back into place in the chainsaw and start the engine again. If this did not help, then it’s time to check the ignition system and the wires connected to the candle.

Chainsaw Doesn’t Stop At Idle | How to Replace a Chainsaw Clutch

If there are large spots of fuel on the spark plug, you will need to check the carburetor of the tool. If a thick layer of black carbon has formed on the part, then the problem may lie in the use of low-quality engine oil. quite often this is the reason why it floods the chainsaw candle. The product must be replaced, and the candle must be thoroughly cleaned with a needle or awl.

When checking the candle, be sure to pay attention to the distance between the electrodes. it should be from 0.5 to 0.65 mm. Very often, too large a distance between the electrodes is the reason why there is no spark.

Chain lubrication system

A rare chainsaw repair manual dispenses with mentioning chain lubrication system malfunctions, which are quite common. They usually manifest themselves in the lack of or insufficient supply of lubricant to the chain and in oil leaks. If the chain turns out to be dry, the first step is to inspect and clean the channels through which the oil is supplied to the bar. Driving them is not uncommon.

In case of significant (small is considered normal) oil leakage, it is necessary to check the tightness of the connection of the pipes to the pump unions. They can subside or crack. Violation of the tightness of the oil line, in addition to drips, can lead to insufficient lubrication of the chain. The pump begins to suck in air, which affects its performance. Violation of tightness is eliminated by replacing the tubes or sealing them with a sealant.

The most serious failure of the lubrication system is cracks in the oil pump housing. In this case, it will have to be replaced.

Engine malfunctions

Chainsaw engine malfunctions occur quite often, it is their detection and correction that takes the most time for users. Basically, they boil down to the following manifestations:

• The engine will not start;
• starts up, but stalls;
• works unstable;
• does not develop power, i.e. works normally at idle, but stalls under load.

When repairing a chainsaw with your own hands, you need to act by the method of exclusion. to check in turn all possible causes of a malfunction, starting with those whose check and elimination takes less time (about the device and operation of a two-stroke engine, see here).

Ignition system. Almost all types of engine problems listed above can be caused by faulty ignition systems. Therefore, when they occur, it makes sense to start troubleshooting with a candle. This is all the more justified since the state of the latter can provide useful information about the operation of the fuel system. So, if a problem occurs, you need to unscrew the candle and inspect it.

The wire is disconnected and the candle is unscrewed with a special key.

If the spark plug is dry, this means that the problem is most likely not in the ignition system, but in the fuel mixture entering the cylinder. You can wrap the spark plug back and start working on the fuel system. If the spark plug is heavily splashed with a fuel mixture, then there is an excess of it. This can occur from a misalignment of the carburetor or a violation of the starting rules. The spark plug is wiped and dried, the cylinder is drained by shutting off the fuel supply and operating with the starter to ventilate the combustion chamber and remove excess fuel. Then put the candle in place and repeat the start.

The presence of a large amount of black carbon also indicates a malfunction in the fuel system.

The ratio between oil and gasoline in the mixture may be disturbed, the carburetor is not adjusted, or poor-quality oil may be used. The candle is washed in gasoline, cleaned with a needle or an awl from carbon deposits, the electrodes are cleaned with a fine sandpaper and installed in place.

In all these cases, it will not be superfluous to check the gap between the spark plug electrodes. Depending on its brand, it should be in the range of 0.5-0.65 mm. It is also necessary to check the spark plug gasket. If it is worn out or damaged, the tightness of the combustion chamber may not be ensured, which leads to a decrease in compression in the cylinder and problems in engine operation.

Even if, when checking the spark plug, there is good reason to believe that the problem is in the fuel system, you need to check the spark plug for the presence of a spark. If only to be sure that everything is in order with this. For this:

Chainsaw Chain Won’t Stop at idleFIX

• put the ignition cable on the spark plug;
• using pliers with insulated handles, apply the thread or nut of the candle to the cylinder;
• pull the starter handle and see if there is a spark or not.

If there is no spark, you just need to replace the spark plug. If the new spark plug does not have a spark either, you need to check the condition of the high-voltage wire for an open circuit and contact with the spark plug.

The reason for the absence of a spark may also lie in a faulty ignition module or a violation of the gap between it and the flywheel magnetic circuit. It should be 0.2 mm. A gap violation becomes especially likely if the saw was disassembled before the flywheel and ignition module were removed. The gap is set with a 0.2 mm spacer placed between the flywheel boss and the ignition module. Defective ignition module must be replaced.

Having checked the ignition system in this way and not finding a malfunction, you can go to the fuel mixture supply system.

Fuel supply system. If by inspection of the spark plug it was found that fuel does not enter the cylinder, all possible reasons for this need to be considered. This could be:

• no fuel flow from the tank due to a clogged hole in its lid (breather), while a vacuum is created in the tank, which prevents fuel from flowing out;
• contamination of the fuel filter installed in the tank;
• non-flow or insufficient flow of the fuel mixture from the carburetor to the cylinder.

To diagnose the first two reasons, it is enough to disconnect the fuel hose from the carburetor and see if fuel is leaking from it or not. If it flows with a full stream, the breather and filter need not be checked, if it does not flow or flows weakly, we can assume that the cause of the malfunction has been found. The breather is cleaned with a needle. The fuel filter is removed through the filler opening of the empty fuel tank, with a wire hook, together with a suction hose from which the filter is disconnected and cleaned or replaced with a new one. Chainsaw manufacturers recommend changing the fuel filter every 3 months.

Insufficient flow of the fuel mixture from the carburetor into the cylinder or a violation of the correct ratio between fuel and air mixed in the carburetor can occur for several reasons: due to clogging of the air filter, unregulated carburetor, clogging of its channels or filter mesh.

As a rule, the repair of chainsaws is not complete without cleaning the air filter, since it gets dirty quite quickly. When this happens, the intake of air into the carburetor is reduced, the fuel mixture at the exit from it is too rich, which disrupts the normal operation of the engine. Remove the dirty filter for cleaning carefully so that dirt from it does not get into the carburetor. The filter should be cleaned or washed in water with some kind of detergent, dried and reinstalled.

The misalignment of the carburetor is eliminated by adjusting it. This is usually done with three screws. the maximum and minimum speed and the idle screw. Adjustment must be carried out in strict accordance with the instructions, non-observance of which may lead to engine damage. Some saw manufacturers keep only one adjustment screw (idle) to prevent unwanted interference by inexperienced users with the carburetor. For an example of adjusting the carburetor of a chainsaw, see the article Working with a chainsaw.

If adjusting the carburetor does not help, you need to clean its channels and filter mesh, and at the same time check the integrity of the membrane. The carburetor is one of the most complex chainsaw devices, so you need to start disassembling and cleaning it with a full understanding of the responsibility of this operation. It consists of many small parts, which have the peculiarity of jumping out of their places imperceptibly and being irretrievably lost, so, having disassembled this capricious device, you may not need to assemble it.

Below is a diagram of another chainsaw carburetor.

If there is no experience and self-confidence, it is better to entrust the repair of the chainsaw carburetor to a specialist of the service center. Sometimes for high-quality cleaning of the carburetor it is necessary to use ultrasonic cleaning.

Muffler. Often, the cause of engine malfunction, especially in the case when the engine normally operates at low speeds and stalls under load, is clogging of the muffler’s spark arrester with combustion products, which prevents normal exhaust. Repair in this case consists in removing the muffler, disassembling (if it is collapsible) and wet cleaning it from carbon deposits using detergents. The non-dismountable muffler is dried with a hairdryer after washing. Remember that carbon deposits contain substances that are carcinogenic, and dry cleaning, due to which they can be inhaled, is not acceptable.. When removing the muffler, plug the engine outlet with a clean cloth.

One of the reasons why the muffler can clog is the use of a fuel mixture with an excessive amount of oil (the amount of oil is more than the manufacturer recommends), and the use of either oil that is not intended for two-stroke engines or low-quality oil.

Cylinder-piston group. Malfunctions of the cylinder-piston group are among the most serious. This is the worn out cylinder and piston, scratches and scuffs on their surfaces, wear or sinking in the grooves of the piston rings, wear on the crankshaft bearings. Most of these faults lead to a drop in cylinder pressure and, as a consequence, to the inability to start the engine, or its inability to deliver full power. There are several ways to assess the state of the cylinder-piston group (CPG).

You can remove the muffler and look through the opened window, in which part of the side surface of the cylinder is visible. Despite the limited review, a general idea of ​​the state of the CPG in this way can still be obtained.

It is useful to measure the compression in the engine, which is quite informative regarding the condition of the parts of the CPG. The operation is carried out using a compressometer installed in the candle hole.

The crankshaft is turned using an electric motor (drill) with a flexible shaft or manually with a starter, while controlling the pressure on a pressure gauge. The latter for a working chainsaw should be at least 8-9 atm (0.8-0.9 MPa). With its decrease, the engine power also decreases. At a pressure of 5 atm, the engine may work, but only at idle.

It is possible to accurately assess the state of the CPG only by completely disassembling the engine. by disconnecting the crankcase from the cylinder and removing the piston. If the latter has seizures, chips or deep scratches, it must be replaced. With regard to the cylinder, if the surface is worn out or damaged, it is possible to bore it to the repair size. The reason for the low compression may be wear or coking of the piston ring. A serviceable ring should be clean from carbon deposits, sit freely in the piston groove and press firmly against the inner surface of the cylinder.

Chainsaw does not cut under load

Even at the same time, it makes strange sounds, then, most likely, the chain tensioning screws are deformed. Defective parts should be replaced immediately for repair.