How To Assemble A Clutch On A Chainsaw

The design and principle of operation of the chainsaw clutch mechanism

Most Sawers DO NOT understand how a chainsaw clutch works. When working, it is not necessary to know the principle of operation, but when malfunctions occur, in order to eliminate them, you will need to find out the design and features of the chainsaw clutch.

Modern chainsaws are equipped with centrifugal clutch mechanisms. Centrifugal clutch. This means that its performance depends on the torque of the engine. The main purpose of the clutch on a chainsaw is to ensure the transfer of torque from the engine crankshaft to the watch headset (chain). The device works in automatic mode, and how it happens, Let’s find out in detail.

The clutch mechanism consists of the following structural elements:

  • Drum with removable or non-removable sprocket. is a transmission mechanism
  • Friction linings. move under the influence of centrifugal force, engaging with the drum
  • Spring. secures the pads against the crankshaft

Now, in principle, the operation of the chainsaw clutch. When the tool’s two-stroke engine starts up, the crankshaft starts rotating. A coupling is attached to the shaft, to which the chain is connected using an asterisk. When the chainsaw is idling (shaft rotation speed up to 2700 rpm), that is, the accelerator trigger is NOT pressed, the spring presses the friction pads, as a result of which torque is NOT transmitted to the drum.

As soon as the sawfly picks up the tool and begins to increase the speed (maximum up to 14000 rpm), the chain begins to move along the tire. This happens due to the fact that the speed of rotation of the crankshaft increases. Due to the inertia force, the friction pads (also called the counterweight) move and engage with the inner walls of the drum. As a result, the drum moves, which is connected to the sprocket. The rotating sprocket drives the chain.

The principle of operation of the mechanism is simple, due to its NOT complex design. If this part fails, then the chainsaw will work accordingly. A detailed description of the principle of operation of the chainsaw clutch mechanism is described in this material.

Design features and clutch operation scheme

Most of the quality chainsaws of famous brands are originally equipped with a centrifugal clutch. It stands out for its high reliability, increased working life and operates in automatic mode, that is, it triggers independently when the power unit reaches the required rotational speed.

The device of the factory centrifugal mechanism structurally includes durable friction linings, a clutch drum for a chainsaw and returnable steel springs. The friction linings of the mechanism can move radially. They are pulled to the crankshaft by springs when the internal combustion engine is operating at low speed.

This principle of operation of the centrifugal clutch has one important advantage. the mechanism automatically slips when the cutting chain is jammed. Thanks to this, the power unit does NOT stall, but continues to work further.

How to remove the clutch from a chainsaw and put it back in place?

Diagram of the process of removing the clutch from a chainsaw (for example, let’s take a situation when a drum needs to be replaced):

Vlad, Odessa:

“In the process of repairing the chainsaw, I had the following situation: the clutch did not give in in any way, and did not want to be removed. Jammed, in a word. This “Dedovsk method” helped: the location of the thread was slightly heated with a burner, very carefully so as not to damage the oil seal. And everything worked out. Maybe someone will use my advice “.

What tool do you need?

To make it easier to remove and disassemble the clutch, you will need the following tool:

  • Puller (included with some saws)
  • Key (also included);
  • Flat screwdriver;
  • A special piston stopper or anything suitable for THESE purposes;
  • Change parts.

How to change the clutch on a chainsaw?

Chainsaw owners have probably wondered more than once. how to change the clutch on a chainsaw? On most models of chainsaws, dismantling and replacement of the clutch can be easily done manually by the owner himself; on a small number of models, unscrewing the drum can only be done in a workshop (such chainsaws include, for example, Husqvarna 137 or Partner 351).

In this review, we will learn how to independently remove and change the clutch on a chainsaw, when to do it and what tools you may need.

The device and principle of operation of the clutch of chainsaws

Modern chainsaws are equipped with centrifugal clutches. This means that their work entirely depends on the engine torque, which at a particular time is given by the saw.

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Its main structural elements are:

  • Drum;
  • Star;
  • Springs.

The principle of operation is as follows. When starting the saw, the elements that move freely in the radial direction are pulled together by springs to the shaft axis. In this case, the torque is NOT supplied to the drum, and therefore to the sprocket and guide. At the moment when the centrifugal force prevails over the force potential of the springs, the clutch elements weaken and compress in the inner part of the drum, initiating its torsion. Together with it, the rotational cycle goes to the sprocket and the most shi-chain headset.

The main advantage of this type of clutch is its slippage when the cutting part is suddenly braked, which does NOT stop the engine. As a result, the “heart” is dust. the motors remain safe and sound.

Chainsaw clutch malfunction symptoms

The centrifugal clutch of the chainsaw works at that time until one of its standard elements fails. In a mechanism breakdown, the operator will be prompted by the following signs:

    The constant rotation of the chain with an unstable operation of the power unit. the main reason for this breakdown is a broken steel spring. To solve the problem, you will need to replace the chainsaw clutch spring. It is important to take into account the design features of the mechanism. For example, the Stihl brand chainsaws have 3 springs and the same number of cams, while Husqvarna models have only 1 spring and 2 cams. If the operator cannot find a new spring, then the entire mechanism will need to be replaced;

In each of THESE cases, it is necessary to disassemble the clutch and inspect all its internal parts. In addition to replacing defective elements, the operator will also need to thoroughly clean the mechanism from dust and small sawdust. this will extend the life of the remaining elements of the factory clutch.

Removing and replacing the coupling with your own hands according to the instructions

Not many sawflies know how to remove the clutch on a chainsaw. The design of devices on different models of chainsaws is different, but the principle of operation is the same everywhere. The dismantling procedure is also almost identical, so further we will consider how to Unscrew the coupling on a chainsaw with an internal sprocket.

Initially, you need to prepare the necessary tools:

  • A special key called a puller. It often comes with a chainsaw
  • Screwdriver for unscrewing the screws that secure the protective cover
  • Spark plug wrench. used to unscrew the casing and tire mount (included with the tool)
  • The rope is for locking the crankshaft. It is better to use asbestos, but any will work for this purpose. The rope is used in case the tool does NOT include a special locking wrench for the piston

If dismantling is carried out for the purpose of replacement, then accordingly it will be necessary to prepare a new mechanism in advance. When buying a new clutch, you only need to know the exact brand of the chainsaw, since the devices differ in the outer diameter, thread and design of the working mechanism. The instruction on how to remove the clutch on a chainsaw is as follows:

  • Initially necessary Unscrew the casing and rail fixing nuts
  • Remove the cover with hand brake, as well as the chain and bar
  • After that, move on to removing the plastic cover to get to the spark plug. To do this, unscrew the fasteners with a screwdriver, and dismantle the cover together with the air filter.
  • The spark plug of the chainsaw is unscrewed with a spark plug wrench
  • A rope must be advanced into the candle hole of the cylinder (install a special key, if available). This is done in order to lock the crankshaft. If the diameter of the rope is several times smaller than the size of the candle hole, you can make knots on it
  • Next, we proceed to unscrewing the coupling itself. To do this, we take a special key, which should be included. If you have a key, then you can use a tool from an angle grinder or make an independent puller, which is also not difficult.
  • The key slots must be installed in the holes of the coupling, after which it will begin to rotate the part. Rotate in a clockwise direction. Usually manufacturers indicate directions for unscrewing in the form of an arrow
  • When the clutch rotates, the piston will reach top dead center, and then lock the crankshaft. Then I applied a little effort, the clutch will break off, followed by unscrewing the mechanism
  • The unscrewed coupling is removed from the chainsaw. If necessary, the drum with an asterisk is also removed
How To Assemble A Clutch On A Chainsaw

The procedure is NOT difficult at all, and does not take much time. Assembly is carried out in the reverse order of removal. To avoid any malfunctions, it is recommended to install a completely identical clutch on the corresponding tool model.

The device and principle of operation of the clutch of chainsaws

Modern chainsaws are equipped with centrifugal clutches. This means that their work entirely depends on the engine torque, which at a particular time is given by the saw.

Its main structural elements are:

READ  How to Adjust Grip on a Chainsaw

The principle of operation is as follows. When starting the saw, the elements that move freely in the radial direction are pulled together by springs to the shaft axis. In this case, the torque is NOT supplied to the drum, and therefore to the sprocket and guide. At the moment when the centrifugal force prevails over the force potential of the springs, the clutch elements weaken and compress in the inner part of the drum, initiating its torsion. Together with it, the rotational cycle goes to the sprocket and the most shi-chain headset.

The main advantage of this type of clutch is its slippage when the cutting part is suddenly braked, which does NOT stop the engine. As a result, the “heart” is dust. the motors remain safe and sound.

When to remove the clutch

Dismantling the clutch for removal is carried out in the following cases:

  • When the spring bursts (the chain turns, the engine runs intermittently)
  • The spring has flown;
  • A piece of drum has broken off (in this case, noise will be heard, the chainsaw chain will also spin)
  • Temporary wear (it’s time to remove and change the clutch due to resource depletion).

Modern chainsaws operate on two-stroke engines, which are connected by a gearbox to the saw chain. The chain moves along the tire, and according to the centrifugal principle, idling must remain stationary, that is, it must be safe for the person who is holding the chainsaw.

If the load on the tool exceeds the recommended load, then the clutch will loosen or completely stop transmitting torque to the tire. This will stop the engine. If such situations arise, the clutch wears out, so it needs to be replaced over time. In the instruction manual for the chainsaw, some manufacturers have information that the clutch is a consumable part, that is, it must be periodically replaced.

how to remove the clutch on a chainsaw:

The design and principle of operation of the chainsaw clutch mechanism

Most Sawers DO NOT understand how a chainsaw clutch works. When working, it is not necessary to know the principle of operation, but when malfunctions occur, in order to eliminate them, you will need to find out the design and features of the chainsaw clutch.

Modern chainsaws are equipped with centrifugal clutch mechanisms. Centrifugal clutch. This means that its performance depends on the torque of the engine. The main purpose of the clutch on a chainsaw is to ensure the transfer of torque from the engine crankshaft to the watch headset (chain). The device works in automatic mode, and how it happens, Let’s find out in detail.

The clutch mechanism consists of the following structural elements:

  • Drum with removable or non-removable sprocket. is a transmission mechanism
  • Friction linings. move under the influence of centrifugal force, engaging with the drum
  • Spring. secures the pads against the crankshaft

Now, in principle, the operation of the chainsaw clutch. When the tool’s two-stroke engine starts up, the crankshaft starts rotating. A coupling is attached to the shaft, to which the chain is connected using an asterisk. When the chainsaw is idling (shaft rotation speed up to 2700 rpm), that is, the accelerator trigger is NOT pressed, the spring presses the friction pads, as a result of which torque is NOT transmitted to the drum.

As soon as the sawfly picks up the tool and begins to increase the speed (maximum up to 14000 rpm), the chain begins to move along the tire. This happens due to the fact that the speed of rotation of the crankshaft increases. Due to the inertia force, the friction pads (also called the counterweight) move and engage with the inner walls of the drum. As a result, the drum moves, which is connected to the sprocket. The rotating sprocket drives the chain.

The principle of operation of the mechanism is simple, due to its NOT complex design. If this part fails, then the chainsaw will work accordingly. A detailed description of the principle of operation of the chainsaw clutch mechanism is described in this material.

Disassembly and assembly of Stihl МС 180

Stihl MS 180 is a reliable and unpretentious tool, but sometimes it requires repair, like any technique. In this article, we will consider how the Stihl MS 180 chainsaw is disassembled, which is necessary in the event of an engine overhaul.

Removing the flywheel

The flywheel of the Stihl 180 chainsaw is twisted with great effort, therefore, to remove it, you will need a head with a metal knob. The nut holding the flywheel is unscrewed by the head by 13.

To block the crankshaft from turning, you need to Unscrew the spark plug and install the piston stopper through the spark plug hole, if it is not there, you can use the old starter cord, with knots imposed on it and immersed in the cylinder through the spark plug hole.

It is strictly forbidden to keep the flywheel from turning by installing a power screwdriver and other tools between its ribs and the body of a power screwdriver, with this method of blocking from turning, the flywheel blades are NOT able to withstand the load and break off.

After the piston is locked in the cylinder, you can unscrew the flywheel nut. The thread in the nuts is common, so you need to turn it to the left. I loosened the nut, it is not necessary to remove it to the end, it is enough to Unscrew it until its upper edge is equal to the tip of the shaft, after which a soft metal drift is installed on the nut and a sharp blow is made on it. Thus, the flywheel from a sharp impact jumps off the shaft and can be easily removed without the help of additional tools.

READ  How to Swap a Chain On a Stihl Chainsaw

How to remove the clutch from a chainsaw and put it back in place?

Diagram of the process of removing the clutch from a chainsaw (for example, let’s take a situation when a drum needs to be replaced):

  • We remove the monitor headset using a universal key;
  • We remove the chain, tire;
  • Unscrew the air filter cover;
  • Next, we twist the candle;
  • We fix the piston with a stopper or rope;
  • Remove the clutch with a punch (puller) or a universal wrench to remove the clutch;
  • Remove the clutch by unscrewing it clockwise;
  • Removing and replacing the drum.

After the steps described above, the entire assembly is carried out in the reverse order.

Vlad, Odessa:

“In the process of repairing the chainsaw, I had the following situation: the clutch did not give in in any way, and did not want to be removed. Jammed, in a word. This “Dedovsk method” helped: the location of the thread was slightly heated with a burner, very carefully so as not to damage the oil seal. And everything worked out. Maybe someone will use my advice “.

When the coupling needs to be replaced

Removal and replacement of the chainsaw clutch is performed in the event of a mechanism malfunction. Such malfunctions include:

  • Damaged spring. Depending on the tool model, the spring can be of two types. coil (tape or single) or steel plate. A spring is damaged by stretching, disconnection or mechanical defect. To determine the cause of the malfunction of the entire mechanism, you will need to remove the protective cover and drum
  • Drum damage and depletion. Breakage of this part is often associated with chipping off pieces. With such a malfunction, you will need to replace the drum. The inner part of the drum also wears out, so the part also needs to be replaced. If the drum is blue, it means that it has been overheated and should not be used further.
  • Development of the mechanism. It is primarily associated with the stretching of the spring, which can be replaced. The threaded connection will also wear out. With such a breakdown, you will need to replace the entire clutch.
  • Sprocket wear. Depending on the type of sprocket (collapsible or non-collapsible), it is replaced with a drum and, if necessary, a clutch

The service life of the clutch mechanism depends not only on the quality of the components, but also on the correct operation of the tool. To extend the life of the chainsaw clutch, you need to pay attention to the signs that reduce the resource. These features include:

  • Frequent seizing or biting of the chain in wood. In such situations, the clutch takes over the entire load, thus protecting the engine from seizure
  • It is forbidden to increase the speed when the handbrake is on, which also leads to wear of the mechanism due to overheating
  • The use of low-quality oil, the wrong choice of tires, chains, etc. All this also affects the adhesion, increasing the load, and thus reducing the service life

Determining the malfunction of the device is quite simple. This requires cutting the workpiece. If, during the sawing process, the chain speed decreases or stops when the load increases, then it is time to check the grip. How to remove and replace the clutch on a chainsaw, we will consider in detail in the next section.

Vladimir Khlestov, 44 years old, Armavir

“After six months of operation, the chain on the chainsaw began to spin constantly. I decided that there was a problem with idling. No carburetor adjustments helped. They took it apart in the workshop. it turned out that the spring on the clutch had burst. We changed everything in 10 minutes, and for two months I could not find a fault. The main thing is the correct diagnosis of the malfunction. “

Yaroslav Nedelko, 31 years old, Vinnytsia region

“I mainly cut hardwood. Quite often you have to sharpen the chain, and the drive sprocket wears out. The first time I removed the clutch. I had to sweat. The metal stuck tightly. it does not unscrew. Sprinkled with kerosene. did not help. Only after using it in Deshki was it possible to break it. And all because the oil was leaking somewhere, so the coupling was welded to the sprocket. I think so. “

Andrey Kosoglazov, 23 years old, Primorsky Territory

“After three months of using the chainsaw, a longitudinal groove appeared in the sprocket. everything works, but the chain does NOT rotate. They said the problem was in the clutch. It is not at all difficult to disassemble it, the main thing is to find a puller and DO NOT forget that the coupling nut has a left-hand thread. In short, I unscrewed and changed everything without any problems. It works perfectly, and there was nothing complicated there, only it was necessary to be careful. “