Replacing Dogs on a Chainsaw Flywheel
A chainsaw is an indispensable tool not only for the summer resident, but also during construction work. If you need to stock up on firewood for the winter, then it does not make sense to go to the forest without a chainsaw. With proper use of the tool, it can last a long time, but in any case, sooner or later, various types of malfunctions will arise. One of these malfunctions is a breakdown of the starter, which makes it difficult to start the engine. In this situation, it is advisable to repair the starter of the chainsaw with your own hands. We learn how to do this in the material.
The device and principle of operation of the chainsaw starter
All types of chainsaws, both Chinese and European production, are equipped with starters of identical design and operating principle. The universal design of starters allows you to use these devices on both branded chainsaws and semi-official tools supplied from China. It is important to note only that some of the distinguishing features of the tools produced in Russia.
A chainsaw starter is a simple mechanism consisting of:
- The cable.
- Handles connecting to a cable.
- Spring return frame.
The principle of operation of such a device is also quite simple. When pulling the handle, which is connected via a cable to the drum of the ratchet mechanism, it moves. During movement, the drum meshes with the slots of another drum, which is located on the shaft. Thus, manually moving the saw crankshaft, which makes several revolutions. As soon as the handle returns to its original position, which is facilitated by the return spring, the spline connection is lost, which leads to a shaft stop. With each movement of the crankshaft in the cylinder, the amount of fuel-air mixture increases, which ultimately contributes to its ignition.
The greater the power of the tool, the more jerks should be made with a starter to start the engine. The return spring is responsible for accelerating the return of the drum to its original position, the manufacture of which is carried out using steel with a high degree of elasticity.
Over time, with constant use of the tool, problems are observed with the engine starting, or rather, with the functioning of the starter. If such problems arise, the starter can always be repaired. If the principle and device of the starter are known, then to do it yourself with your own hands will not be difficult at all.
Typical breaks and repair of a chainsaw starter
Before carrying out repairs, it is necessary to find out the causes of the breakdown. Since the product is constantly subjected to dynamic and other types of loads, its failure is not excluded. Common causes of starter breakdowns are: a broken cable, abrasion or chipping of several splines of the ratchet drum, spring damage, a pulley crack, and others. To determine why the saw does not start, you will need to conduct an appropriate audit of the starter mechanism. Consider the main types of malfunctions, and also find out how to properly repair the product.
The starter cord is a strong rope that is durable enough to wear, but even its technical properties do not save it from damage. Each time the tool is started, the rope rubs against the housing of the starter cover, which leads to its gradual grinding and wear.
If the cord was rubbed, then to replace it, you will need to disassemble the body of this node. After removing the cover, it is necessary to lift the drum, but only in such a way that it does not slip out of its seats. It is recommended that such work be carried out together with a partner who will fix the spring, and you will be engaged in replacing the cable. The remnants of the old cable should be removed, and then fix the new product in the handle and in the groove of the drum. After this, the cable should be wound on the roller, and at the end assemble the housing.
It’s important to know! Before fixing the cable in the handle, pass it through the corresponding hole in the starter cover.
How to replace the chainsaw starter spring
If spring damage is observed, which is often the case with Chinese tools, then the mechanism can only be repaired by replacing it. But if its damage occurred at the point of accession, that is, the ear burst, then it can be repaired.
Repairing a spring is heating the place of destruction to 600 degrees, and then slowly cooling it to 100 degrees, at which to complete the wrapping of the end in the form of a fragment. Thus, it will be possible to avoid loss of elasticity of the product, which will extend its service life. Although most experts simply replace the product with a new one.
The spring replacement process is carried out in the following sequence:
The detailed spring replacement process is discussed in the:
Replacing the flywheel dogs
If it is necessary to replace the dogs or flywheel replies, then this is also not difficult. To do this, you will need to dismantle the flywheel, and then remove the dogs. Install new dogs should be exclusively those that were originally (plastic or metal). This is very important, since replacing plastic dogs with metal ones will lead to accelerated wear on the flywheel. Details of replacing the chainsaw starter dogs are discussed in the below.
In conclusion, it is important to note that to repair the chainsaw starter, you do not need to have special skills or experience. All work can be done independently, if you take the repair process with all responsibility. Timely preventive maintenance of the chainsaw will avoid breakdowns when performing work in the field.
Today we will consider problems with malfunctioning chainsaw starter and we will eliminate them. This type of breakdown is not uncommon during heavy use of a gasoline-powered saw. And in our case. At logging, this happens systematically.
I had a chance to repair starters from the Ural chainsaw, with which we felled, working in the leshoz. I was still very young and understood the design for the first time, myself. The malfunction has arisen as a result of breaking the “tongue” of the spring, which is fixed in the drum (housing).
So, the chainsaw starter is designed to start the tool. On gearless saws, it is located in the side cover on the flywheel side (left side of the tool). This is a purely mechanical principle of action. But in order to correctly and properly repair the starter, it is necessary to understand the principle of its functionality (work). I propose a thorough consideration of this issue.
On top of the starter cover (housing), the handle is located in a special seat on the cover. The handle is connected to a cord, which in turn is wound on a pulley and the end of the cord is secured with a pulley. When the operator (the user of the chainsaw) jerks the handle up, the cord unwinds along the pulley (coil), bringing it into a “centrifugal” state.
But, as lumberjacks know, a pulley happens with a ratchet without characteristic teeth. Gears. These are classic professional chainsaws, the ratchet of which is either a steel “cup” of small diameter with side cutouts (protrusions), or plastic analogs (grips). For example, on Calm 361, the ratchet has grips in the form of “dogs”. It is with these “notches”, “grips” or “dogs” that the adhesion to the “dogs” on the shaft occurs. The principle of operation of the “doggies” splines, I think, is understandable. When the shaft accelerates in rotation, the “dogs” slip through the ratchet.
Let’s take a look at the general starter circuit.
In addition, the starter comes with a damper spring, the so-called “easy start” Smart start. On the model of a chainsaw with an “easy start”, the letter “e“(E.G. Husqvarna 340e) However, there are models of professional chainsaws without the letter “e”, since they have no analogues without the Smart Start system. The starter cover, with the presence of a damper spring, looks more convex. By the way, damper springs break quite often than the main spring.
So, you have “covered” the chainsaw starter. If the cord simply breaks, then the malfunction is “obvious” and should be replaced. Other characteristic symptoms of a starter malfunction are as follows:
- The shaft does not catch (the winding cord freely scrolls);
- After a jerk of the winding, the cord does not unwind;
- Starter jams
Chainsaw starter repair
First of all, it is necessary to twist and remove the cover, make a visual inspection. A breakdown of the chainsaw starter can be different. A bursting spring, a defect in the pulley (“coil”), a worn-out cord.
Next, we prepare repair tools. These are screwdrivers and pliers. In the event of a break, you will need a new cord. I think that lumberjacks have a cord for the starter in stock. If there is no possibility of acquiring a factory cord, then you can replace the “forced” with a clothesline, choosing the appropriate diameter.
In the event of a break in the cord
We turn out the starter mounting screw, remove the clamp and the damper spring, if any, on your brand of chainsaw. We dismantle the pulley with the cord, untie or cut off the cord assembly, and remove it. Since the cord is torn, the spring is discharged, and, in principle, you can not be afraid of falling out of the spring from the cover.
We take a new cord, select the appropriate length (focusing on the length of the old dangling cord), divide, melt the ends of the cord so that they do not “shake”. We insert a new cord into the coil, tie a fixing knot and “hide” it in a pulley for unhindered passage of the cord along the brook of the coil (on some chainsaw models the cord is tied around a ratchet. This is provided for in the design). Pass the free end of the cord through the hole in the starter cover and push it into the handle. We fix the cord in the handle with the help of a knot. We wind the cord onto the reel (pulley) in the corresponding direction. We place the pulley in the starter cover over the return spring (and over the damper if present) and make sure the spring is engaged with the coil. Slightly turn the coil in the corresponding direction. We fix the pulley with the fixing screw.
Next, you need to charge (cock) the spring. To do this, pry the free part of the cord with a screwdriver and pull it out. We grab the cord with your hand, put it in the technological half-hole, which is located from the edge of the coil. We make several turns by turning the coil (pulley) by the cord in the direction of tension.
How many turns do?
Too weak a tension will “break” the edge of the pulley housing, and too much tension will adversely affect the return spring. Pick up the tension yourself.
When the spring is charged, the starter is put in place. The cover is screwed to the chainsaw. During tightening, the mounting screws are slightly tightened, and the starter must be turned to fully fit and engage the pulley with the “flywheel” of the flywheel.
If the shaft does not catch
When trying to start a chainsaw, the jerk of the cord is “idle”, i.E. No gearing with the shaft. The operator inconclusively makes jerks of the starter, the cord is unwound on the pulley without resistance and rewound. What is the reason?
The malfunction is in a burst damper spring (“easy start”,”soft starter”). If you remove the starter cover, then the breakdown is detected without difficulty, since most often the spring bursts closer to the cover. However, not the damper spring itself, but its mounting location may break.
If the spring burst, then only a replacement with a new one will help to eliminate the malfunction. That is why, I am not a fan of chainsaws with a soft start system. Of course, I do not impose my tastes and opinions on any of my colleagues. Everyone has the right to decide his own preferences in this choice of chainsaw model.
Another reason for the lack of traction on the shaft may be a ratchet defect. We are talking about a ratchet model with a plastic gear, when the teeth for gearing have cracks and chips. In this case, it is also necessary to replace this unit. That is, the ratchet mechanism. And it is better to have a chainsaw model with steel ratchet.
By the way, the “dogs” on the flywheel shaft can also cover themselves. To burst the springs, which perform the return function and as a result, the clutch with the ratchet disappears. A similar malfunction has also occurred in my personal practice. The springs of the “dogs” were made from fragments of a cable (from cores). But it was worth an incredible patience, time and concentration. I am sure that you should not like to pervert and work out with another chainsaw.
Another reason when the shaft does not catch is the common mistake of collecting the starter again. Fixing it to the flywheel. This picture is observed in inexperienced lumberjacks. The reason is the lack of engagement of the coil with the “dogs”. The fact is that during the final fastening of the cover, the user of the chainsaw does not check the engagement by turning the starter and the ratchet lies on top of the “dogs”, and in this case there is no engagement. An inexperienced operator is perplexed and does not understand the cause of the malfunction. It disassembles and reassembles until it realizes (or until a more experienced colleague tells you) about the proper assembly of the starter.
If the starter sticks
The picture, when the starter is jammed, looks as follows: the operator jerks the cord by the handle, and the cord either does not move at all (the pulley does not turn), or with great difficulty “passes a short distance” and finally stops. Of course, no return movement of the cord to its original position occurs.
I am sure that most lumberjacks are familiar with this picture. The cause of the malfunction is the deterioration of the pulley, and more precisely in the support casing, which holds the cord in the “stream” of the pulley. The cord extends beyond the edges of the housing, creeps out, it is rubbed between the edge of the casing and the pulley, and the cord loses its ability to curl up to its original position.
To continue work, it is necessary to rewind the cord to the pulley, “charge” the spring. To start a chainsaw, it is necessary to “catch” the engagement, carefully pulling the cord by the handle up and only then pull it. The cord must be in a taut position when jerking to prevent it from falling out of the coil body. This method will help only for a short time using the tool, as the wear of the assembly is unremovable. It is necessary to quickly replace the starter coil with a new one.
Attention should be paid to one important nuance: during dismantling of the pulley it is important that the return spring (if it is intact) does not fly out of the seat. Otherwise, you get tired of collecting the spring in the bay and put it in place. In order to avoid the return spring falling out of the seat, it is necessary to discharge it first. This is done as follows: the cord (closer to the handle) is picked up with a screwdriver and placed in the technological half-hole of the pulley. Next, you need to pull the cord and make several turns in the opposite direction of winding, until the spring is loose. Another option is to unload the spring. Cutting the cord at the base of the handle, but by doing so you will sacrifice a small piece of the cord. When removing the pulley, you need to make sure that there is no clutch between the spring and the pulley.
If the return spring burst
The return spring is used to wind the cord onto the pulley and is located under the pulley. If it burst, and this depends on the resource (as a rule) of the tool operation, then there is only one way out in this situation. Replace the spring with a new one. It’s possible, of course, to distort and “blind” a fragment into a short analogue, but this is only when the “edge” is really necessary and the work on the cutting area needs to be completed. The end of the spring band will need to be annealed to take the form of a locking hook. Such forced absurdities occur, as a rule, on a shift and the “Russian peasant” has to “surprise the world” (or amuse) with his ingenuity. But in fact, to eradicate the need to feed the family.
If the spring burst, then for replacement we remove and discard its remains. In its place we install a cove of a new spring. We cover the spring with a protective cover.
The coil (pulley) is mounted on the spring (over it). After that, it is necessary to rotate the pulley, making sure that the coil engages with the return spring. Then we proceed in the sequence indicated in the chapter “In the event of a break in the cord”.
Write comments, supplement if I missed something, didn’t finish it, or made a mistake somewhere. I will be glad to our discussion.
How it works.
In order for the engine to start, it is necessary to give the crankshaft and flywheel initial rotation. This is achieved by transmitting torque from the starter pulley, driven by a person by pulling the cord.
The starter pulley has special fangs-hooks (one, two or four, depending on the design). When you start pulling the cord, the pulley turns and the fangs-hooks engage with the flywheel dogs. Next, together with the pulley, you rotate the flywheel and crankshaft. When the engine starts, the flywheel dogs will disengage from the pulley.
After you release the handle of the starter, the cord is wound back onto the pulley with a special return spring. It is located under the pulley between it and the starter housing.
How does a starter with a “smooth” or “easy” start.
To facilitate the start-up procedure, special modifications of the starter type such as “soft start” or in another way “erogostart”, “easy start” are produced. The purpose of this modification is to eliminate the need for a sharp force movement. “Smoothness” is achieved by installing an additional spring already inside the pulley itself.
Schematically, it works like this. The pulley is divided into two parts: one part contains fangs, hooks, a cord with a handle is wound around the second drum part, which you usually pull. Both parts are connected to each other by a spring.
When you start pulling the cord, the flywheel dogs engage with the fangs on the starter pulley. Then the additional internal spring is compressed: on the one hand, the spring is held by the engine compression force through the engagement of the dogs with fangs, and you pull the other end, pulling the starter cord. At the same time, the part of the pulley with fangs remains stationary, and the drum part rotates on the contrary. Due to this, the spring is compressed. As soon as the spring force of elasticity becomes greater than the compression force, it begins to expand and rotate the engine crankshaft.
Important findings right away: At first, in a starter with a soft start, it does not matter how much and sharply pull the cord. Until the spring is properly compressed, the saw will not start. It can be compressed slowly, but it can be quickly. The result will be the same. Secondly, For the spring to give its compression energy to the crankshaft, it is necessary that it unwinds from one end. Therefore, after you have pulled the cord, you must hold it at the top point for a few moments.
Rules for using starters.
Starter made of plastic. It’s easy to break it. To avoid this, you must follow simple rules and read the instruction manual.
For starters with an “easy” start.
Remember, the engine starts the spring. You just squeeze it.
- Do not use excessive force.
- For a moment, hold your hand at the top so that the spring unwinds from the crankshaft side.
- Do not often pull the starter. Often, “poking” for the starter, you do not unwind the crankshaft. You just break the spring. Read what is written above about the delay at the highest point.
In winter, Chinese grease may freeze in the springs. To prevent this from happening. Without PULLEY DISASSEMBLY, drip a couple drops of engine oil under the springs. It will slightly dissolve the Chinese solidol and freezing will not occur.
The damage shown in the photo is caused solely by improper operation. This has nothing to do with the quality of materials and the manufacture of starters. These are solely operational errors. These ARE NOT WARRANTY CASES.
Photo OF TYPICAL Failures of STARTERS.
The device and principle of operation of the chainsaw starter
Most well-known chainsaw manufacturers equip their products with starters that work on almost the same principle. Its essence is as follows: in the groove of the saw body there is a handle through which a cord is passed. With a sharp lifting of the handle, the cord is also pulled, which engages the drum, which is in the ratchet mechanism. By means of this, a drum with spitz, which is located on the shaft, is driven. During this, the crankshaft makes a couple of revolutions, which leads to compression of the fuel mixture, which at this moment is between the cylinder head and the piston. When lowering the handle, on the contrary, the ratchet and spitz lose their contact, which leads to a shaft stop.
With an increase in the power of the chainsaw, the amount of the fuel mixture increases, which must be ignited when the chainsaw is started. In this case, to start the engine, it is necessary to increase the number of jerks of the starter cord. To accelerate the return of the drum mechanism, manufacturers use a special steel recoil starter spring with excellent elasticity. To facilitate the launch of the chainsaw, leading brands use other methods:
- Pre-enrichment of the fuel mixture with a separate shutter;
- Installation of an automatic decompression valve, which provides a decrease in pressure inside the cylinder of the chainsaw;
- Installation of a primer designed for pumping fuel before starting the engine.
The use of one of these technologies greatly facilitates the launch and extends the life of the starter, which is especially noticeable at low temperatures.
Typical breaks and repair of a chainsaw starter
The appearance of various malfunctions of the starter leads to the inability to start a chainsaw. The most common starter breakdowns include:
- The starter pulley has completely burst, or cracks have appeared on it;
- The spring burst;
- The starter cable broke.
Do-it-yourself tools will be required to fix each of these malfunctions. You must have a set of screwdrivers and a spare cable with you. Remove and inspect the starter for the chainsaw in the following order:
- To find the cause of the breakdown, the starter from the chainsaw will need to be removed. To do this, unscrew the screws with which the protective cover is held with the starter attached to it;
- After removing the cover, you must carefully unscrew the screw through which the starter is attached to the protective cover;
- Then you need to try to smoothly start the starter. For this, remove the spring and clips from it;
- Further, a coil with a cable is removed from the starter for inspection.
As a result of inspection, you can find a number of typical malfunctions. These include:
- Various pulley damage in the form of tears or cracks mainly in the rear of the part. They interfere with the normal operation of the entire starter;
- Damage to the starter spring of a light start. In such cases, not only the spring itself can be faulty, but also the place of its fixation. This is the most vulnerable part of the spring;
- The starter flywheel dog is damaged.
In any case, any defective part must be completely replaced with a new spare part.
Chainsaw starter diagnostics
Due to the long-term operation of the chainsaw, the trigger mechanism becomes unusable. After one or several jerks, the crankshaft does not rotate when pulling the starter rope. This problem can be caused by the following reasons:
- Cracked or broken drive pulley;
- The chainsaw starter spring burst;
- A gust of rope launch.
Before starting work on the diagnosis and repair of the start-up mechanism, it is necessary to prepare the necessary tools and accessories that will significantly reduce the time for operations. These include:
- A set of bench screwdrivers and a specialized set of proprietary tools included in the scope of supply of the chainsaw.
- Strong cord to replace a worn starter rope.
At the first stage of repair of the chainsaw starter, it is necessary to identify the nature of the problem. To do this, remove the side cover from the side of the start mechanism, while unscrewing only a few screws. Depending on the manufacturer, this operation will require a specialized or conventional locksmith screwdriver.
Next, we inspect the inside of the protective casing. In the absence of cracks and chips of plastic, we proceed directly to the diagnosis of the launch site. We unscrew the central bolt of the starter and dismantle the spring. No cracks or gusts should be observed on its surface. It is problematic to choose a spring similar in strength and number of turns on your own, therefore the help of specialized centers will be required.
After removing the clamp and the starter spring of the chainsaw, a pulley with a wound cord is accessible for dismantling. The integrity of the rope indicates that it is necessary to carefully review each of the details of the trigger mechanism.
Repairs start mechanism
When inspecting a disassembled starter, it is necessary to inspect the following parts (nodes) for damage:
- Drive pulley. A pulley subjected to high axial and radial loads should not have cracks or damage on the back side. If any, it is necessary to replace it with a new part.
- Starter Spring The main load when starting a chainsaw is tested by a spring. Made of high-quality carbon steel and specially heat-treated, it loses its properties over time. If cracks or gusts are detected, a new spring will be required.
- Rope launch. Made from synthetic wear-resistant materials, the starter cord wears out over time. With his gusts, it is necessary to install a new rope on the pulley.
Spare parts purchased must comply with the regulations for the particular model of the chainsaw.
After the repair work is carried out, it is necessary to assemble the start mechanism in the reverse order. A ratchet pulley is mounted on top of the spring. Before the final fixation of the chainsaw starter cover, it is necessary to wrap the rope and make several trial jerks.
It must be remembered that the starter cord is previously threaded through the hole in the cover.
Tips from professionals
For the exact orientation of the holes in the body and the rope fixing channel, you may need to make 2-3 turns.
In order to prevent slipping of the cord from the pulley, it is necessary to tie a knot larger in diameter than the hole in the housing. In the absence of wear (damage) of the spring, it is installed first when assembling the starter of the chainsaw. A pulley and a starter clamp are mounted on top of it, preventing the skew of the mechanism during rotation.
As it turns out, do-it-yourself starter repair does not require special skills and tools. However, it is necessary to approach the restoration of the start-up mechanism responsibly and from time to time carry out preventive examinations.