How To Count The Links Of A Chainsaw

Required tools

Chainsaw manufacturers say that shortening the chain at home is unrealistic, because the very development of their production is very difficult and requires high-precision equipment. I will say right away that at least in the chainsaw chain and how to measure and choose the step, size, chain length. Practice shows that nothing is unrealizable. In order to shorten the chain, you will need:

Connecting links

If all the characteristics of the chain are mixed with the parts of your chainsaw, then you can start connecting the links. We connect the links to a rivet, pressing their side parts tightly. It will no longer be possible to rivet the protrusions, because they are grinded flush with the links. We’ll have to use electric welding. For this you need to take an electrode with a smaller diameter.

Determination of chain wear: a. wear of teeth, b. installation of an additional fixing plate on the key link.

It is not recommended to immediately start welding, because this is a very narrow job. how to sharpen a chain sharpening a saw chain from a chainsaw on a machine bought in. Practice doing this on other details first. So you will at least roughly understand at what current you need to cook and what welding time to choose. Well, the electrode will become shorter, which will allow you to weld more accurately. A very short period of time is enough to “grab” a rivet. After training, we weld the rivets to the lateral parts of the link. It remains only to grind off excess metal on both sides with a file and the chain can be considered ready for use.

How to Know Your Chainsaw Chain Size

Chain marking for chainsaws

In some situations, the owners of chainsaws may experience some confusion in their awareness of all the chain markings for these tools. This size is what you can tell about the chainsaw chain. how to find out what step the chain has. This will ultimately lead to bad purchases. The choice of chainsaws is often determined by only a few basic aspects, one of which is the chain pitch. This indicator helps to highlight the future capabilities of the tool, including its cutting speed, and, according to the norms, must correspond to the level of motor power. How are chains marked? Let’s figure it out!

How to Measure the Length of a Chainsaw Chain AURAMM.RU

Chainsaw bar length. How to measure and choose the pitch, size, length of the chain for. I will say right away that at least in the chainsaw chain and how to measure and choose the step, size, chain length. Is it necessary to consider?

A chainsaw is one of the most necessary and practically available tools for any conscientious owner: neither the summer resident nor the owner of a private house can do without it. Procurement of firewood, pruning of trees and shrubs, construction or repair of arbors, benches, verandas, etc. the chainsaw is always the first assistant in such household chores. Chainsaw chain sharpening the number of links determines the chain length, how to determine. Professional craftsmen on harsh construction sites and logging sites will not do without it.

Saw chain technical parameters

When choosing a chain for a chainsaw, you need to pay attention to several important characteristics:

• number of links;
• chain pitch;
• the thickness of the driving link;
• purpose of use.

In addition, on our website you can choose a chain according to the saw model through the chain saw guide.

Number of chain links. Determined by the internal teeth of the chain.

Chain pitch is the distance between three consecutive rivets divided by two. This is a defining parameter, and depending on its value, all existing chains are subdivided into five groups with a step of 1/4 ”, 0.325 ”, 3/8 ”, 0.404 ” and 3/4 ”.

1/4 ” (6.35 mm) pitch for small chains used on low-power single-handed saws.

Chains with 0.325 ” (8.25 mm) and 3/8 ” (9.3 mm) pitches are the most common options. than 80% of the saws produced worldwide are equipped with them.

Pitch 0.404 ” (10.26 mm) and 3/4 ” (19.05 mm) feature larger chain links and higher performance. For several decades, they were used to complete Russian-made saws, but now they are installed only on powerful felling saws and harvester equipment.

The larger the chain pitch, the larger the links that make it up and the higher its productivity, but the wider the cut. A more powerful saw is required to overcome the increasing cutting resistance. Chains with a small pitch have other advantages. more teeth per unit of length, smoother movement in the cut and, accordingly, less vibration, cleaner cut.

Drive link thickness. During operation, the chain slides in the groove of the tire, and this sliding should be smooth, without snagging and at the same time without unnecessary “bumpiness”. The thickness of the shank and the thickness of the groove must strictly correspond to each other, which increases the reliability of the chain fit and excludes the possibility of its “dismounting”. Everything is provided in five standard sizes:

• 1.1 mm (0.043 ”) for low power saws
• 1.3 mm (0.050 ”) household and semi-professional chains,
• 1.5 mm (0.058 ”) powerful and productive saws,
• 1.6 mm (0.063 ”) and 2.0 mm (0.080 ”) high performance saws.

The intended use imposes its own requirements on the circuits used. For example, when sawing hard and contaminated wood is required, or when demolishing and building structures. it is better to use special carbide chains Picco Duro or Rapid Duro, which have carbide teeth or pads that give them unmatched strength and durability. Some work simply cannot be done without their help.

It is also known that for longitudinal sawing of wood (along the grain) it is desirable to use special chains. The main difference between longitudinal and transverse type chains is the angles of attack of the cutting links. For crosscut chains, they are 25-35 degrees. Rip saw chains (e.g. Stihl Picco Micro X chains) have sharper angles. 5 to 15 degrees.

The use of chains inappropriate for their purpose leads either to reduced performance, or to increased “aggressiveness”, strong vibration and additional load on the chainsaw engine.

Additional chain characteristics include profile height and cutting depth.

Profile height. Chains come in high and low profile depending on the height of the cutting edge above the plane of the guide bar. High profile chains are generally used for professional purposes to get the best cutting performance. Low-profile chains are installed on household and amateur chainsaws, because Increased cutting link bearing area and reduced chip thickness are safer.

Depth of cut is the amount of clearance between the top of the tooth and the cut stop, which controls the thickness of the chips. Most often there are samples with gaps of 0.025 inches (or 0.635 mm) and 0.030 inches (or 0.762 mm), less often. with gaps up to 0.07 inches (or 1.778 mm), the latter are intended for machine felling units.

The depth of cut determines the cutting performance to a large extent. The larger the gap, the higher the performance. The downside to performance is vibration. So chains with a shallow depth of cut in the kerf move softer, less “twitch”. Therefore, to balance vibration and productivity, cutters with a shallow depth of cut are often installed on a chain with a large pitch, and vice versa.

How Many Links Are In A Chainsaw Chain AURAMM.RU

Chainsaw chain markers

In some situations, the owners of chainsaws may experience some confusion in the awareness of all the markings of the chains for these tools. The angle of sharpening of the chainsaw chain can be changed, depending on what kind of work will be done. This will ultimately lead to poor purchases. The choice of chainsaws is often determined by only a few basic aspects, one of which is the chain pitch. This indicator helps to highlight the future capabilities of the tool, including its cutting speed, and, according to the norms, must correspond to the level of motor power. How are chains marked? Let’s figure it out!

A step is an intermediate distance between 3 rivets that are placed side by side. For the correct calculation of the chain pitch, the distances between the axes of the three rivets placed close to each other should be frozen. In the form of a formula, it looks like this:

L = S / 2

Where, L is the step length, which in chainsaws characterizes the degree of remoteness of 2 teeth in relation to each other;

S. the value of the gap between the last 2 rivets of the three.

The step size can also be equal to the length of the distance between 2 adjacent shanks.

Regularity: the greater the distance between the cutting teeth, the deeper they will enter the material being cut

By increasing the size of the chain pitch, it becomes possible to increase the performance of the chainsaw. But, in a similar case, the degree of force applied to implement the rotation of the drive sprocket changes. And the higher the chain pitch, the greater the power of the engines should be and the more physical forces are expended to pull it when cutting materials.

How to choose a chain for a chainsaw

In this video I will tell you how to choose a chain for a chainsaw, what types of chains are there and which chain is right for you.

Tools that you need to shorten

You can properly shorten the chainsaw chain with your own hands using special tools.

Rivet Removing Machine

For disassembly, a specialized machine is used. a punch. The machine is designed as a small mechanical press. In its lower part, a removable anvil is installed, which has grooves of different sizes. The working rod of the device also has nozzles of different diameters. This makes it possible to use the machine for chains from different manufacturers. The rivet is removed by squeezing it out of the seat.

Caution: The diameter of the removable stem tip must not exceed the diameter of the hole in the side plates.

Rivet setting machine

After disassembling and removing the chain element, the working links must be reconnected. A riveting machine is used for this purpose. The assembly process takes place using a special work roller, which is driven by an electric motor.

The rivet is clamped between the stationary anvil and the work roll. The operator independently sets the pressure of the work roller using the adjusting screw. During the rotation of the roller, the edge of the rivet is gradually crushed, which makes it impossible to detach the links from each other.

Reference: using machines to shorten the chainsaw chain allows you to bring the build quality as close as possible to the factory sample. However, these devices are quite expensive, and their purchase for home use is unprofitable. In addition, it is not always possible to use specialized devices right at the workplace. In this regard, shortening can be performed with improvised tools.

How to shorten a chainsaw chain with your own hands. procedure

Often, during the operation of the chainsaw, the saw chain stretches, which makes it impossible to further use the tool. Today, there are specialized workshops that provide services for shortening chainsaw chains, but it is possible to shorten the chainsaw chain with your own hands at home or right at the workplace.

Reasons for chain stretching

The chain of a chainsaw, regardless of the manufacturer, can stretch for several reasons:

• Incorrect operation of the oil pump. Insufficient oil supply leads to overheating of the chain and its rapid stretching.
• Natural wear and tear. Occurs as a result of prolonged use of the tool.
• Use of poor quality lubricant.
• Violation of the rules for operating a chainsaw.

Important: If any irregularities in the operation of the oil pump are detected, it is necessary to eliminate the malfunctions, ensure the normal lubrication of the saw blade. Failure to do so may result in drive sprocket failure. You should also pay attention to the quality of the oil. The presence of various kinds of abrasive microparticles in the oil is not allowed.

Rivet removal methods without the use of specialized devices

There are several ways to remove rivets without using specialized tools:

• Grind off the protrusions on the emery. When using this method, it is necessary to control the degree of pressure on the rivet in order to avoid damage to the working parts.
• Cut with the cut-off wheel of an angle grinder. It should be borne in mind that in this case the metal heats up, which will affect its properties.
• Cut the heads with a file or file. With this method, the risk of link damage is minimized.
• Chop down using a chisel. Before starting work, you will need to securely fasten the chain in a vice.

After the outer protrusions are completely cut off, you will need to knock the rivet out of the seat. To do this, you need to select a punch, the diameter of which will correspond to the diameter of the hole. The punch must be put on the rivet and knocked out with a sharp blow of a hammer. After completing these steps, the chain will be disconnected.

Caution: To avoid damage to the links, secure them securely. In addition, the punch should be installed strictly perpendicular to the rivet cut.

How to rivet a chainsaw chain

To assemble the chain, you will need to install a repair link on it. It must be borne in mind that its dimensions must strictly correspond to the dimensions of the working links. Installing a spare part with a different pitch or profile can damage the drive sprocket, driven sprocket and saw blade of the chainsaw.

The repair link is sold with rivets that you just need to fasten. To do this, you need to lay the chainsaw chain on an anvil. After that, put the punch on the new rivet and flatten the head with a sharp hammer blow. Riveting is necessary until the resulting thickening covers the hole in the outer plate.

When flattening, control the degree of clamping of the side plates. After assembly, the installed link should move freely along the axis. Installing a chain with a jammed link on a chainsaw is not allowed. Failure to follow this rule can lead to more serious damage to the device.

Some people use electric arc welding machines for assembly. In this case, the rivet edges are welded to the outer link plates. The use of electric welding involves heating the metal to a high temperature. As a result of overheating, the properties of the metal change, it becomes less wear-resistant.

Recommendation: after assembling and installing the part on the chainsaw, you need to check its performance with a minimum load. Only in case of normal operation can the load be increased.

From the information described above, it follows that chain stretching on a chainsaw is a fairly common phenomenon. It is quite possible to shorten the chain at home, you just have to enlist the traditional tools that almost every owner has in stock.

Is it possible to shorten the chain yourself

In the case when the chainsaw chain has stretched so much that it is no longer tensioned, it becomes necessary to reduce its length.

This also has to be done if the available bar is shorter than the chain, and it is not possible to choose a suitable saw element.

Rules for replacing and tightening chains on a chainsaw

The chain tension on the chainsaw affects not only the normal operation of the machine, but also the safety of the operator working with it. A chainsaw is a highly traumatic tool, and a loose saw chain can have dire consequences. In turn, an over-tensioned chain increases the load on the tool. Therefore, before each start-up of the machine, you must make sure that this important element has the correct tension.

How to remove a rivet

To change the elements of the chain or shorten it, you will need to separate the links as follows. Fix the chain element in a vise and grind off the rivets, namely their protruding parts. You can use a file or file for this. Be careful not to grind the side of the link.

It is not recommended to use an angle grinder, since there is a risk of overheating the links, which will lead to a change in the physical properties of the metal.

Using a beard (as it looks like in the photo below), knock out a rivet.

There is another option for separating the links. To do this, you do not need to grind the heads of the rivets. Place the link, namely its rivet, over a hole in the metal or over the slightly parted jaws of the vise. Next, you should put a locksmith barb on the rivet head and hit it several times with a hammer.

Continue knocking out both rivets alternately as they are firmly secured by the opposite side of the link. Gradually, the rivets will begin to come out of the top of the link, and it will come loose.

The advantage of this method is that the rivets can be reused as they do not grind.

Tension Algorithm

Before tensioning the chain on the chainsaw, you must turn off the engine of the unit, or disconnect it from the mains if it is an electric saw. Do not adjust or replace the saw blade while it is hot. If this is done, the metal will shrink after cooling and the tension will be too great, which can lead to increased stress on the engine and deformation of the tire.

The chain tensioner is located on the right side of the machine, under the cover, in the place where the clutch brake is installed and the bar mount is located. On Husqwarna, Stihl, Poulan and Partner chainsaws, the external tensioner looks like an ordinary bolt.

So, in order to adjust the chain element of the apparatus, you need to perform the following steps.

• Loosen the nuts on the right side cover slightly so that the tire is not skewed.
• Insert a screwdriver into the tensioner adjusting bolt and turn it to the right (clockwise). From these actions, the tire will begin to move, and the chain will tension. If you turn the bolt to the left (counterclockwise), then the chain links will relax.
• Next, you should tighten the chain to a state so that it does not sag and dangle.
• Check the tension of the element: grasp the cutting link approximately in the center of the bar and pull it down with a slight force. The chain should be taut, have elasticity, and the shank of the cutting link should fit into the groove of the bar by about 1/3 of its height.

On a Makita electric saw, the tension adjuster is designed in such a way that it can be turned without the use of any tools. Turning it clockwise will tighten the chain, if you turn the adjuster in the opposite direction, the tension of the chain element will loosen.

Chainsaw saw element replacement

If you need to replace the chain on the chainsaw, then follow these steps.

• Remove the cover covering the sprocket. To do this, most often it is necessary to unscrew the fastening nuts.
• After unscrewing the fasteners, remove the cover covering the clutch with an asterisk.
• Grasp the bar with your hand and push it towards the sprocket to loosen the chain.
• Remove the chain element from the drive sprocket.
• Now you need to install the chain on the chainsaw. Take a new saw unit and slide it onto the drive sprocket first.
• Then you need to put the chain on the tire, placing the element in its groove around the entire perimeter. It is important that the links fit properly onto the driven sprocket on top of the tire. Pay attention to the direction of the cutting links when installing. They should be directed away from the unit, on the top of the tire.
• Run the bar in the opposite direction to the engine to tighten the chain a little.
• After laying the saw element, before putting the cover back in place, it is necessary to align the screw, through which the tension is adjusted, with the adjuster located behind the bar. Only then can you put on the cover and screw the nuts slightly. Next, insert a screwdriver into the adjusting screw and apply the final tension. How the correct chain tension is made was described above.
• Raise the bar slightly and tighten the nuts, thus securing it. It is important not to overdo it and not to rip the thread.

The main problems with the chainsaw chain

Chainsaw users are often faced with the problem of saw chain tension. It either weakens spontaneously, or stretches and flies off. As a rule, these troubles are caused by unit breakdowns. Therefore, before proceeding with the chain link tensioning procedure, you should check and eliminate possible causes that may lead to a misalignment.

Chainsaw chain stretching can be caused by heavy loads or insufficient lubricant supply to the tire. This causes the saw to overheat, expand the metal, enlarge the saw element, and fly it off the bar. Oil flow can be disrupted if the pump breaks down, channels clogged, oil hose breaks.

If you changed the chain on the chainsaw to a new one, then be prepared for the fact that during the running-in period it will stretch a little. It is only necessary to check the tension in time so that the element does not fly off the tire.

A chain made of low-quality steel also stretches quickly.

Making up chainsaw chain by hand. No spinner No breaker.

When the driven or drive sprocket is worn, the grip on the chain links decreases, causing the saw element to fly off. In this case, you will have to unscrew the chain drive and change the sprocket. Also, the saw blade of the unit can fly off due to its stretching or deformation of the tire.

If the chain on your chainsaw weakens, then a malfunctioning tension mechanism can cause this malfunction.

How to determine the degree of tension

A quick check of the chain tension is very simple: you need to grasp the prong and pull it up. If the chain is tensioned correctly, then the tail will be immersed in the groove of the bar by 1/3 of its height. An excess of this indicator indicates excessive tension, and a decrease in the indicator indicates weak.

Normally, the saw should move freely along the tire, without much effort. If the movement of the element is difficult, this is a sign of excessive tension.

With a strong tension on the cutting element of the chainsaw, the tire begins to heat up and grind, the load on the engine increases, and it wears out quickly. Do not start up the machine with a loose chain, as it may pinch and break when sawing, which poses a danger to the user of the machine. The chain can fly off the tire and injure limbs, and it often breaks itself and damages the tire. Also, work with a weakened chain element leads to one-sided tire wear, after which the device stops making even cuts, and the saw is taken to the side.

How to connect links

Do not be afraid to rivet, as the rivet has a thickening in the central part, which serves as a stop.

Some craftsmen advise joining the links by welding. This method will work if the rivets have been filed off. But first you need to experiment on some piece of iron in order to choose the appropriate welding mode.

Welding must be carried out with a short and thin electrode. The rivet is welded to the side of the link and the excess metal is removed with a file. The only drawback of this method is overheating of the metal from which the circuit elements are made. As mentioned above, due to overheating, the wear resistance of the links may decrease.

Chain tensioning mechanism

For added convenience, the chain tensioning screw can be located on the side.

Engine

The chainsaw engine has a maximum speed of about 13,500 rpm. This imposes strict requirements on the oil added to the fuel mixture.

Carburetor

Below is a diagram of another chainsaw carburetor.

Carburettors have a throttle valve that allows leaning or enriching the mixture depending on operating conditions. For fine tuning, there are several screws with which the low and high engine speed and idle speed are adjusted. An air filter is installed on top of the carburetor, which cleans the air entering it.

Clutch

At low speeds, elements with friction linings (1), having a degree of freedom in the radial direction, are attracted to the center of the shaft by springs (2) and do not transmit rotation to the drum (3) connected to the sprocket of the driving chain. When the engine speed of the chainsaw reaches values ​​at which the centrifugal force exceeds the force of the springs, the friction segments are pressed against the inner surface of the drum and begin to rotate it. As a result, the drive sprocket starts to rotate, driving the saw chain.

As seen in the photo, the sprocket is behind the clutch.

What is Pitch, Drive Links & Gauge in chainsaw?

On other chainsaws, the sprocket may be on the outside of the clutch.

The main advantage of clutches of this type is that when the chain is jammed, the chainsaw clutch slips without muffling the engine and without causing breakdown of the mechanisms that transfer movement from the engine to the chain.

Starter

The starter mechanism consists of a drum (1) with a cable (2) and a handle (3), and a frame (4) with a return spring. When the handle is pulled up sharply, the drum ratchet engages the teeth on the engine shaft and turns the crankshaft. When the handle is released, the return spring returns it to its original position.

It takes a certain amount of force to turn the crankshaft at the speed at which the engine starts. It is often not possible to start the chainsaw with one jerk, you have to pull it several times. Various methods are used to facilitate start-up. enrichment of the fuel mixture using the carburetor flap, or reducing the pressure in the cylinder using the decompression valve (to facilitate crankshaft cranking). The valve is made to automatically close when the pressure in the cylinder rises when the mixture is ignited. Sometimes an additional spring is used in the starter mechanism, which, when the cable is pulled out, is first compressed, and then abruptly unclenched, spinning the motor.

The main and most complex chain links are cutting links, which are subdivided into right-handed and left-handed. Top edge of the tooth. the widest of all elements. It provides a wide kerf to prevent the remaining links from getting stuck.

The shape of the cutting teeth can vary significantly from chain to manufacturer. There are two main forms. chipper (a) and chisel (b). However, there are also different intermediate contours of the incisors.

Tooth cutting edges. side and top. sharpened at a specific angle. For rip sawing chains, it is 10 °, for crosscut. 30 °. Rip saw chains are rarely used. If necessary, rip sawing can also be done with a cross saw chain. Read more about chainsaw chain sharpening angles in the article Chainsaw chain sharpening.

The main characteristic of a chain is its pitch. To establish the chain pitch, measure the distance between the midpoints of the first and third rivet rivets (see figure below) and halve this dimension. The result obtained. chain pitch in mm. However, in most cases, the chain pitch is given in inches. The distance between the centers of the first and third rivet rivets is measured because the distance between the holes of the driving links and the cutting links or connecting links can vary in magnitude. The most common chains are 0.325 and 3/8 ” (8.255 and 9.525 mm, respectively). Chains with a pitch of 0.325 are used with low-power engines (up to 40-50 cm 3), while powerful chainsaws are usually equipped with 0.404-inch chains (such chains have a higher performance). The cut is cleaner and more accurate when sawing using a chain with a smaller link thickness and a smaller pitch.

Shank thickness is an important characteristic. There are five standard thicknesses: 1.1, 1.3, 1.5, 1.6 and 2 mm. The most common chains are 1.3 mm (0.05 “) shank. They are widely used on both household and professional chainsaws. The thickness of the drive links must be matched to the width of the guide bar groove so that the saw chain fits perfectly on the guide bar.

Chain manufacturers use different technologies to make them and use different materials. The defining characteristic of the latter is not hardness (teeth that are too hard do not lend themselves well to manual sharpening), but toughness and impact resistance. It is they who determine the durability of the chain. Therefore, wear-resistant alloy steels are used in the manufacture of cutting teeth. Cutters are often chrome plated to increase their surface hardness. Some firms use shot blasting to increase the toughness of the teeth.

To guide the chain, the tire has a guide groove along its periphery, in which the driving links of the chain move. The groove of the groove also serves as a channel for supplying oil for lubricating the chain. The main parameters of the tire include:

• Dimensions of connecting holes (a), depending on the type of chainsaw.
• The width of the groove (b), which should correspond to the thickness of the shanks of the chain used. The groove width of the bar is only a few hundredths of a millimeter wider than the thickness of the drive links of the respective saw chains. This enables precise lateral guidance of the saw chain.
• The pitch of the end sprocket (c), which also determines the compatibility of the used chains with the bus.
• Cut length (g), which determines the size of the workpiece material. tree trunk diameter, etc.

Air purification system

Pre-filters can have different designs and consist of several elements, in particular, from a mesh (2) and snow (1) filter (see photo below).

The latter prevents snow from entering the air cleaning system and is used only in winter, at positive temperatures it is removed.

In some models of chainsaws, at the pre-cleaning stage, air is purified using centrifugal forces. The air flow is twisted by the impeller of the flywheel, as a result of which impurities are thrown away from the suction pipe to the fine filter.

Fine filters are made of diffusion foam, nylon mesh and other materials.

When a chainsaw is in operation, the air in the area of ​​its action is highly contaminated with sawdust and wood dust. Excessive contamination of the filter reduces the volume of air entering the carburetor, which leads to a richer mixture and a decrease in the power of the chainsaw. Therefore, regular cleaning of the filter is necessary. It should be carried out not only when the chainsaw is being disassembled for the purpose of repairing it, but much more often, after any lengthy and dirty work. Cleaning is carried out using a method that depends on the type of filter material. most often by blowing and flushing.

Chainsaw device

In addition to the listed nodes, chainsaws have a system for cleaning the air supplied to the carburetor, a tire with a saw chain, a starter, a chain tensioner, ignition, a muffler, etc.

Fuel system

So that, as the fuel mixture is consumed, the fuel tank is filled with air and a negative pressure is not created in it, which will prevent fuel from flowing from it to the carburetor, and at the same time, so that fuel does not flow out of the air hole, the cap covering the filler hole is made breather. And by the way, if the breather gets clogged with dirt, the chainsaw will stall.

From the tank, fuel is pumped through a hose freely dangling in the tank. Thanks to this, regardless of the position of the chainsaw, the hose is always submerged in fuel. A fuel filter is attached to the inlet end of the hose. The fuel is pumped by the pump inside the carburetor.

To facilitate starting, some of the chainsaws are equipped with a manual pre-priming pump. primer. When starting a chainsaw with a primer, the carburetor is filled with fuel in advance (excess fuel flows back into the tank). This allows the engine to start faster because the stage of filling the carburetor with fuel has already been passed, which, without a primer, is performed by the carburetor pump due to the starter.