DIY chainsaw manual starter repair

Any chainsaw requires a starter to quickly start. With accelerated scrolling of the crankshaft of the tool, the fuel-air mixture supplied to the engine is compressed and subsequently ignited. Therefore, the normal operation of the starter for a chainsaw determines the performance of the entire mechanism.

Almost all leading manufacturers of chainsaws complete their products with starters of a similar principle of operation. It is no coincidence that specialized stores offer universal starter designs that are equally successful for both Shtil, Husqvarna, Makita chainsaws, and for Chinese semi-official fakes under the named trademarks. Only domestically produced chainsaw starters (Lesnik, Ural and a number of others) have some features.

The principle of operation of a starter for a chainsaw is as follows. A handle is installed in the groove of the body through which a cable is passed. If the handle is lifted sharply, the cable is pulled out and engages the drum of the ratchet mechanism, which transfers the movement to the drum with splines provided on the shaft. In this case, the crankshaft makes several revolutions, and the working mixture in the space between the piston and the cylinder head is compressed. Accordingly, when the handle is lowered, contact between the ratchet and the splines is lost and the shaft stops.

With an increase in engine volume, the required amount of the fuel-air mixture required for its subsequent ignition also increases, so the number of jerks for the starting cable for high-power saws increases. Therefore, in order to accelerate the return of the drum, unwanted return springs made of steels with high elastic properties are used.

Facilitation of starting the chainsaw is implemented in the following ways:

1. By preliminary enrichment of the working mixture, for which there is a special damper in the carburetor design.
2. Installation of an automatic decompression valve, which reduces the working pressure in the chainsaw cylinder.
3. Installing an additional spring, which, during the movement of the cable, facilitates the unwinding of the crankshaft.
4. The presence in the design of some chainsaws (for example, Partner S series, Maxcut, etc.) a primer - a pump that provides preliminary fuel pumping.

With frequent starts of the chainsaw, some parts of the starter are constantly subjected to dynamic loads. As a result, the cable may burst, several ratchet teeth crumble, and the shaft will turn at a much lower speed. Therefore, the revision and even repair of the starter are operations that are sometimes carried out several times per season.

When pulling it out, the rope is constantly rubbing against the starter housing. To replace, disassemble the body of the unit, and carefully raise the ratchet drum so as to prevent the return spring from jumping off its seats. It is better to do this work together: the assistant fixes the spring while the cable is being replaced. After fixing the cable in the handle and in the grooves of the drum, the cable is wound around the roller, and the body is assembled.

If the material of the starter spring is found to be of poor quality, the spring will burst (usually at the point where it joins the drum, where it forms a loop). In this case, it is not worth replacing the spring.Thoroughly clean its surface from dirt and traces of grease, carefully grind the place of destruction, and then release the spring at 600 ... 650 ° C (the steel of the spring should acquire a crimson color). It is necessary to cool the spring slowly, and at 100 ... 150 ° C it is already possible to carefully wrap its end in the shape of the restrictive protrusion on the inner surface of the drum (the steel will acquire the necessary plasticity) and insert it into place. The elastic properties of the spring will not change.

Fitting the starter spring into the correct groove is not easy, even for an experienced user. First, the spring should be twisted to the previous diameter and installed in the cavity of the drum hub. The outer end of the spring is fixed by the restrictive protrusion, and the outer end with a screwdriver should be positioned opposite the hole in the lock. The loop at the inner end of the spring is aligned with the hole with a screwdriver, after which the disc is lowered. Rotate the disc to check if the ratchet dog has come into place. Next, the ratchet itself is assembled.

After installing the spring, it is necessary to adjust its tension. To do this, a cable is inserted into the groove on the circumference, and a return spring is twisted around it. After removing the slack, it is best to wind the spring an additional few turns to ensure the required tension on the part.

Repairing the ratchet itself at home is not recommended, since many operations will require the use of a CNC machine. It is easier to purchase a new unit in specialized stores.

Today we will consider the problems with chainsaw starter malfunctions and we will eliminate them. This type of breakdown is not uncommon during intensive use of a gas-powered saw. And in our case - at logging, it happens systematically.

I had a chance to repair starters from the Ural chainsaw, which we used to cut wood while working in the forestry enterprise. I was still very young and I was dealing with the construction for the first time myself. The malfunction has arisen due to the breakage of the "tongue" of the spring, which is fixed in the drum (housing). I remember how I was all in graphite grease (hands and face) trying to tame the "snake" (metal tape), which "fell apart" into rings and did not want to gather in the bay))). I think who collected (twisted) the spring remembers , as the palms of the constant resistance of the spring convulse. The repair was aggravated by a metal cable. Nevertheless, I successfully coped with the task, although it took me a lot of time and nerves. On chainsaws of world brands, the design is not so complicated and capricious.

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 operation. But in order to correctly and efficiently repair a starter, it is necessary to understand the principle of its functionality (work). I propose to consider this issue in the most thorough way.

Above the cover (body) of the starter there is a handle in a special seat of the cover. The handle is connected to a cord, which in turn is wound around a pulley and the end of the cord is secured to the pulley. When the operator (the user of the chainsaw) jerks the handle up, the cord unwinds along the pulley (reel), bringing it to a “centrifugal” state. The pulley has a ratchet in its design (on the back side) - this is a gear with teeth rounded to one side. The teeth of the gear (ratchet) mesh with the "pawls", which are located on the drum (flywheel) of the crankshaft. The crankshaft rotates, the fuel is compressed under the pressure of the piston and the engine head. Meanwhile, the operator lowers the handle, the return spring, which is fastened to the reel (pulley), winds the cord back to its original state (onto the reel).The ratchet teeth, meanwhile, slide over the flywheel pawls, excluding contact with them, since they are already rotating in the opposite direction. Let me remind you that the ratchet teeth are rounded in one direction - this is the principle that allows engaging with the crankshaft pawls. By rotating in the opposite direction, engagement with the "dogs" is excluded.

But, as loggers know, a pulley comes 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 these “notches”, “grips” or “pawls” that engagement with the “pawns” splines on the shaft takes place. The principle of operation of the splines-"dogs", I think, is clear - when the shaft accelerates in rotation, the "dogs" slip along the ratchet.

Let's take a look at the general starter circuit.

In addition, the starter is available with a damper spring, the so-called "easy start» Smart Start... On the model of a chainsaw with "easy start", the letter "e"(Eg 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 more often than the main spring.

On a watch we faced a similar problem - on the Husqvarna 340 delimbere the spring has burst (there is no damper spring on the analogue of the Husqvarna 340). And on watch, every hour of road work, they worked according to a 10 × 4 scheme. It was not possible to replace and fix the breakdown. I had to use a "horned" chainsaw and a bumper to cut off branches from time to time so that there was no downtime at the tractor driver. The lopper had to take the ax. The next day we changed the starter - we put in a cover from a similar chainsaw (I don't remember the model, but not the Husqvarna 340), which had a design without a damper spring. Of course, the lid did not fit completely, there was a gap on top, but the seat did fit. However, this was the only solution to the problem, there were no specialized stores in that backwater, except for the grocery store ...

So, you have a chainsaw starter. If the cord just breaks, then the malfunction is "obvious" and it should be replaced. Other characteristic signs of a malfunctioning starter motor are as follows:

• the shaft does not seize (the winding cord turns freely);
• after a jerk of winding, the cord does not reel;
• starter jams

The first step is to twist and remove the lid, make a visual inspection. Chainsaw starter breakdown can be different - a broken spring, a defect in the pulley ("coil"), a worn winding cord.

Next, we prepare tools for repair - these are screwdrivers and round nose pliers. In the event of a break, you will need a new cord. I think the lumberjacks have a supply of starter string. If it is not possible to purchase a factory cord, then you can replace the "forced" with a clothesline, choosing the appropriate diameter.

We unscrew the starter mounting screw, remove the clamp and the damper spring, if there is one on your brand of chainsaw. We dismantle the pulley with the cord, untie or cut off the cord knot, remove it. Since the cord is torn, the spring is discharged, and, in principle, there is no need to be afraid of the spring falling out of the cover.

We unscrew the screws securing the starter

The cord is torn, the spring is discharged, there is no need to be afraid of the spring falling out of the cover during parsing.

Dismantle the torn pulley cord

Removing a fragment of the torn cord from the handle

We take a new cord, select the appropriate length (focusing on the length of the old broken cord), divide, melt the ends of the cord, so that they do not "shake". We push a new cord into the coil, tie a fixing knot and “hide” it in the pulley for the cord to run smoothly along the coil stream (on some models of chainsaws, the cord is tied around the ratchet - as provided by the design). We 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 using a knot. We wind the cord onto the reel (pulley) in the appropriate direction. We place the pulley in the starter cover over the return spring (and over the damper, if any) and make sure that the spring is engaged with the coil - slightly turn the coil in the appropriate direction. We fix the pulley with a mounting screw.

We measure the new cord by the length of the damaged cord

We melt the end of the cord, before threading it into the pulley so that they do not "shake".

We push the melted end of the cord into the technological hole through the pulley

We push a new cord into the spool.

Tie a knot at the end of the starter cord using round nose pliers

We “hide” the knotted fixing knot in the pulley for the smooth running of the cord along the reel stream

We pass the free end of the cord through the hole in the starter cover and push it into the handle.

We push the free end of the cord into the handle.

Tie a knot at the end of the cord in the handle for fixing

We melt the free knot of the starter cord in the handle

Next, you need to charge (charge) the spring. To do this, pry on the free part of the cord with a screwdriver and pull it out. We grab the cord with our hand, place it in the technological half-hole, which is located at the edge of the coil. We make several turns, turning the coil (pulley) by the cord in the direction of tension.

Pry on the starter cord with your fingers or a screwdriver, pull it back and wind it on the reel.

We wind the cord on the pulley in the direction of tension

We make several turns of the cord on the pulley for acceptable tension

Too little tension will "break" the edge of the pulley housing, and too much tension will negatively affect the return spring. Adjust the tension yourself.

We check the tension of the cord in the starter by pulling it up by the handle

Reinstall the starter cover and fasten with screws

When the spring is charged, the starter is installed in place - the cover is screwed onto the chainsaw. During screwing, the fastening screws are slightly tightened, and the starter must be turned to fully seat and engage the pulley with the flywheel pawls.

When you try to start the chainsaw, the pull of the cord is "idle", ie there is no engagement with the shaft. The operator jerks the starter to no avail, the cord unwinds along the pulley and unwinds without resistance. What is the reason?

The malfunction consists in a burst damper spring ("easy start», «soft start mechanism"). If you remove the starter cover, the breakage is easily detected, since most often the spring bursts closer to the cover. However, it is not the damper spring itself that can break, but its attachment point.

If the spring has burst, then only replacing it 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 their own preferences in this choice of the chainsaw model.

Another reason for the lack of reliable engagement with the shaft may be a defect in the ratchet. We are talking about a model of ratchets with a plastic gear, where the teeth for engagement are cracked and chipped. In this case, it is also necessary to replace this unit - that is, the ratchet mechanism. And it is better to have a model of a chainsaw with a steel ratchet.

By the way, the "pawls" on the flywheel shaft can also get covered - the springs, which perform the function of a return, burst, 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 rope fragments (from the veins). But it was worth incredible patience, time and concentration. I am sure that you should not be similarly perverted and work with another chainsaw.

Another reason when the shaft does not seize is the banal mistake of reassembling the starter - attaching it to the flywheel. This picture is observed among inexperienced lumberjacks. The reason - the lack of engagement of the coil with the "dogs". The fact is that during the final screwing of the lid, the user of the chainsaw does not check the engagement by turning the starter and the ratchet rests 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. Disassembles and assembles again until he guesses (or until a more experienced colleague prompts him) about the correct assembly of the starter.

The picture, when the starter jams, looks like this: 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, there are no return movements of the cord to its original position.

I am sure that this picture is familiar to most lumberjacks. The cause of the malfunction lies in the worn out pulley, or, to be more precise, in the support casing, which holds the cord in the pulley “stream”. The cord extends beyond the edges of the case, crawls out, it is rubbed between the edge of the casing and the pulley, and the cord loses its ability to roll back to its original position.

To continue working, you need to rewind the cord on the pulley, "charge" the spring. To start the chainsaw, you need to "catch" the engagement by carefully pulling the cord up by the handle and only then pull. The cord must be taut when pulling to prevent it from falling out of the reel body. This method will help only for a short time of using the tool, since the wear of the assembly is unavoidable - it is necessary to promptly replace the starter coil with a new one.

You should pay attention to one important nuance: during the dismantling of the pulley, it is important that the return spring (if it is intact) does not fly out of the seat. Otherwise, you will get tired of collecting the spring into a coil and putting it in place. In order to avoid the return spring from falling out of the seat, you must first discharge it. 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 out the cord and make several turns in the opposite direction of winding until the spring weakened. Another option to deflate the spring is to cut the cord at the base of the handle, but this will sacrifice a small piece of the cord. When removing the pulley, you must make sure that there is no spring engagement with the pulley.

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 operation of the tool, then there is only one way out in this situation - to replace the spring with a new one. You can, of course, be perverted, and "blind" from fragments of a short analogue, but this is only in the case when it is really "edge" and it is necessary to finish the work on the cutting area. The end of the spring band will need to be annealed to take the shape of the fixing hook. Such forced absurdities occur, as a rule, on watch and the "Russian peasant" has to "surprise the world" (or amuse) with his ingenuity. But in reality, eradicate want in order to feed the family.

If the spring has burst, then for replacement we remove and discard its remnants.In its place we install a new spring coil. We cover the spring with a protective casing.

The coil (pulley) is installed on the spring (on top of it). After that, it is necessary to turn the pulley, making sure that the coil is engaged with the return spring. Next, we proceed in the sequence indicated in the chapter "In the event of a break in the cord".

Write comments, add if I missed something, did not finish writing something or made a mistake somewhere. I would be glad to have our discussion.

A chainsaw is an indispensable tool when cutting firewood and felling trees. Following the manufacturer's recommendations and carrying out the necessary preventive measures will ensure a long "life" of the unit. But even the most reliable mechanism has problems over time, most of which can be eliminated by hand without the help of specialized centers. One of these malfunctions may lie in the chainsaw starter, which can be repaired independently, subject to a certain sequence of operations.

Due to the long-term operation of the chainsaw, the starting mechanism becomes unusable. After one or more jerks while pulling the starter rope, the crankshaft will not turn. This problem can be caused by the following reasons:

• cracked or broken drive pulley;
• the chain saw starter spring burst;
• burst rope launch.

Before starting work on diagnostics and repair of the launch mechanism, it is necessary to prepare the necessary tools and accessories, which will significantly reduce the time for operations. These include:

1. A set of locksmith's screwdrivers and a specialized set of branded tools included in the delivery of the chainsaw.
2. Durable lanyard for replacing a worn launch rope.

Chainsaw starter spring

At the first stage of repairing a chainsaw starter, it is necessary to identify the nature of the problem. To do this, remove the side cover from the side of the starting mechanism, while unscrewing only a few screws. Depending on the manufacturer, this operation will require a specialized or conventional plumbing screwdriver.

Next, we inspect the inside of the protective casing. In the absence of cracks and chips of plastic, we proceed directly to diagnostics of the launch unit. We unscrew the central bolt of the starter and dismantle the spring. There should be no cracks or gaps on its surface. It is problematic to choose a spring similar in force and number of turns on your own, therefore you will need the help of specialized centers.

After removing the clamp and the chainsaw starter spring, a pulley with a wound cord is available for dismantling. The integrity of the rope indicates that every detail of the launch mechanism needs to be carefully reviewed.

When inspecting the disassembled starter, it is necessary to inspect the following parts (assemblies) for damage:

Chainsaw starter cord replacement

1. Drive pulley. A pulley subject to high axial and radial loads should not be cracked or damaged on the rear side. If any, it is required to replace it with a new part.
2. Starter spring. It is the spring that experiences the main loads when starting the chainsaw. Made of high quality carbon steel and specially heat treated, it loses its properties over time. If cracks or tears are found, a new spring will need to be installed.
3. Launch rope. Made from durable synthetic materials, the starter cord will wear out over time. If it bursts, it is necessary to install a new rope on the pulley.

The spare parts purchased must comply with the regulations of a particular chainsaw model.

After the repair work has been carried out, it is necessary to assemble the starting mechanism in the reverse order.The ratchet pulley fits over the spring. Before the final fixation of the chainsaw starter cover, it is necessary to wrap the rope and make a few test jerks.

It must be remembered that the starter cord is first threaded through the hole in the cover.