A chainsaw is a tool that is useful in any country house, even for amateurs, not to mention professional workers. But, like any other device, a chainsaw needs constant care and prevention. One of the most common procedures is to adjust the carburetor of a chainsaw due to incorrect settings in the past.
The first signs of a carburetor malfunction
Due to untimely or unprofessional periodic maintenance of the chainsaw, as well as due to heavy load, difficulties in its operation may arise from time to time. For professional workers, such breakdowns can reduce their work efficiency and spoil their mood for the whole day.
Carburetor malfunctions, in turn, have specific symptoms. Using them, you can immediately determine the cause of the breakdown.
The following signs indicate an incorrect carburetor setting:
In the event that dirt gets into the carburetor, one adjustment will not do. Here you just need to clean it. When the pistons are used up, you need to do major renovation engine.
But after this, of course, you need to adjust the carburetor jets, as well as purge and clean them.
Operating principle
The purpose of the carburetor is to prepare the working mixture for supplying it to the engine cylinders. This mixture is gasoline and air in the proportions required for engine operation. If this ratio is violated, the engine will not operate smoothly. When the mixture has a lot of gasoline, then in layman's terminology it is called saturated, and if, on the contrary, there is little, then it is lean. But in any case, a failure in the proportions of the working mixture will have a bad effect on performance.
Different chainsaw models may have different designs carburetors, but according to the principle of operation they are all identical. Air moves through a special channel at a speed that can be adjusted by closing or opening the damper. Gasoline, in turn, enters the carburetor through jets and mixes with air there, creating a special mixture that enters the engine.
The pressure in the float compartment of the carburetor, where gasoline is present before mixing, is close to atmospheric. When the damper is opened, there is more air, as well as gasoline, due to which the engine speed increases. IN air channel this creates a vacuum and gasoline is drawn into the air flow. This is the principle of operation of a carburetor..
In order for the chainsaw to operate smoothly and efficiently, and also without high fuel consumption, its carburetor must be adjusted accordingly. Before such work, you must first check the air and gasoline filters. If dirt is found on them, they should be replaced.
Setting up a chainsaw for most models is usually done using three screws - high and low speed and idle speed.
The following signs should indicate correct configuration:
- The chain should not move at idle.
- The motor runs smoothly.
- There should also be no interruptions in work at start-up.
Repairing a chainsaw carburetor with your own hands must be done very carefully, because any mistake made can lead to serious consequences, even to the point of complete engine failure. If you do not have enough experience, it is better to seek the help of a specialist..
Adjusting the Husqvarna chainsaw
During the break-in period of the Husqvarna chainsaw 142, 240, 236, 137 and other similar models, the carburetor settings are set in such a way that the engine speed is 600-700 less than normal operating speeds. If the operating frequency cannot be adjusted using the tachometer, it is not recommended to reset the factory settings using screw H.
The manufacturer strictly prohibits exceeding the working speed on your own. When, after adjusting the carburetor, the chainsaw chain moves at idle, then by turning screw T counterclockwise you need to stop it.
To fine-tune the saw, it must be installed on flat surface tire forward. You also need to warm up the engine for at least 12-15 minutes. First you need to determine the highest idle speed number. To do this, screw L in the chainsaw must be turned clockwise, and then in the opposite direction. After determining the desired frequency, the same screw is turned counterclockwise from 12 to 25% of its full revolution.
The idle speed in models from this manufacturer is adjusted using a jet with the letter T. The adjustment is made by turning it clockwise until the chain moves. After this, turn it easily counterclockwise until the chain stops moving.
The H screw of the chainsaw is adjusted correctly only when the saw does not make much noise when the gas is pressed all the way, and at the same time it is not weighed down by any load.
In the case when the saw is too noisy during operation and smokes, then this jet must be turned from left to right for adjustment.
Saws Shtil and Partner
In chainsaws Shtil 250, 361, as well as Partner 351, 350, the carburetor is adjusted using screws H and L by setting the proportions of gasoline and air. If you release them, a large part of the fuel will be added and therefore the speed will be high, otherwise, on the contrary, it will drop.
Idle speed in Partner chainsaws is regulated using a screw with the letter T, but in Shtil, as a rule, you need to look for the LA marking. Standard adjustment of the chainsaw is carried out during final tests. Basically, after such settings, the percentage of fuel in the working mixture is greater than air, which does not correspond to the optimal parameters. But they must be preserved during the first hours of operation during the running-in of the device. After this, the saw can be adjusted independently, but it will work well even at the factory settings.
But if you decide to regulate yourself, then the actions must be performed in the following sequence:
- adjusting screw L;
- then adjust the jet H;
- after that, proceed to adjusting the idle speed using screw T (if the Shtil chainsaw is LA).
First, screw L must be turned in both directions in order to find the maximum engine speed. If that point is found, then turn the same screw by ¼, thereby slowing down the speed a little. If the chain continues to move at idle, you must immediately turn screw T (LA) until the chain stops completely.
After setting the maximum speed with screw H, you need to check the frequency on the tachometer. In the event that it does not correspond to those specified in the service book, the setting must be repeated. When a lot of smoke comes out of the exhaust pipe at maximum speed, the mixture is too rich in fuel; if noise is heard and the engine gets very hot, then on the contrary, it is lean. Then you need to adjust the idle speed. With proper settings, the engine should sound smooth at low speeds, and the chain should not move.
Chinese models
Adjusting the carburetor of a Chinese chainsaw, for example, Carver, is carried out in almost the same way as factory models. There are the same three main adjustment screws L, N, T. Sometimes such models have the ability to adjust the idle speed. But as a rule, employees of specialized services and owners of such saws claim that it is not always possible to set up a high-quality Chinese chainsaw right away.
For classic Chinese models, screw L should be loosened 1.5 turns from the maximum value. Screw H must be loosened one turn from the maximum. Idle speed is adjusted in the same way.
Thus, self-adjustment The chainsaw carburetor is not very complex process and can in most cases be carried out self-taught.
A carburetor such as we will consider is installed on many saws of similar brands such as Poulan, Mc Culloch, Max Cut, CHAMPION
We unscrew all three screws (as shown on the indicators) and remove the top cover of this saw from the body.
We remove the air filter from our housing (shown in the figure) - a filtering foam air element (green foam in the figure).
Unscrew two nuts at once and remove the air filter housing itself.
In order to remove this air filter housing, it is simply not enough to simply remove it from two bolts. He won't take off. The protrusion indicated on the arrow will interfere with it.
You need to apply very little upward force to the filter housing, until the protrusion is slightly higher than the very top edge of the chainsaw housing, and remove it.
We work on the right side of the carburetor. We remove the fuel hose (as on the top arrow) and then the choke drive rod.
Finally, we remove the carburetor and remove the tip of this cable from the throttle valve drive lever.
On our left side we also pull the gasoline hose together from the carburetor fitting.
The carburetor is now removed and ready for further disassembly.
In the example we are considering - a chainsaw, confusingly, that is, there is no gasoline in the gas tank. Therefore, when we removed the gas hose on the right side of this carburetor, fuel did not come out of the hose at all. Your tank may also be full, and therefore not much time may pass after working with the saw.
During operation, the fuel in the tank is under slight pressure, so after removing the hose from it, fuel will begin to flow out.
Prepare in advance a clothespin or clamp or an ordinary 13 nut.
We completely unscrew the idle speed screw and the screw securing the carburetor cover on top.
Then remove the top cover. This will open an area of the carburetor called - fuel pump where the blue transparent gasket is the fuel membrane.
On the left side of the carburetor, remove two screws (according to the instructions, the screws are marked L and H), first removing the spring bracket from them. When assembling the carburetor, these screws cannot be mixed up; screw H has an annular groove; if it is not there, mark the screw with any one.
Remove the four screws from below and remove the very bottom carburetor cover.
Remove the needle valve assembly. For this purpose, remove the screw indicated by the arrow in the figure. Under the two-arm lever, don’t lose it, there is a small spring.
Champion chainsaw carburetor: and its adjustment
We begin the adjustment by adjusting the idle speed; to do this, rotate the T screw (LA) counterclockwise, achieving a complete stop of the chain at stable engine speeds.
Champion chainsaw carburetor design
Detailing a chainsaw carburetor
For further precise adjustment, you will need a tachometer and it is better to entrust it to specialists, especially since in most cases it may not be needed.
Adjusting the carburetor of the Patriot 4518 chainsaw
We start setting up the tool with screw L, then use screw H and finally screw T (LA).
We find the highest idle speed, to do this we slowly turn screw L in different directions. After finding the position of the highest engine speed, turn screw L 1/4 turn counterclockwise. If the chain rotates at idle, screw T should be turned counterclockwise until it stops.
Screw H regulates power and speed. Adjusting the carburetor to a lean mixture leads to excessive speed, engine overheating and failure of the piston chainsaw.
Warm up the chainsaw engine at idle speed for at least 10 seconds and turn screw H 1/4 turn counterclockwise. Let the engine run for about 10 seconds, then check the maximum engine speed with a tachometer. If the maximum speed does not correspond to the specified speed, the operation should be repeated. When the mixture is supplied too rich, the muffler begins to smoke; when the mixture is too lean, the saw squeals and overheats. 
We complete the adjustment by adjusting the idle speed, as already described above. The idle speed is set correctly if the engine runs smoothly at minimum speed and the chain does not rotate.
The carburetor can be considered adjusted if the engine accelerates quickly and sounds like a four-stroke at full throttle.
This is important!
As you know, the “Champion” chainsaw enjoys well-deserved popularity in our country both among construction and logging organizations, as well as among many owners of personal plots and country cottages. This increased demand for a chainsaw is primarily due to its rather long service life and its absolute reliability in operation.
And for the Champion chainsaw to work properly, you need timely adjustment of the carburetor, which not only ensures efficient operation of the entire tool, but also significantly extends its service life.
And such adjustment can only be carried out with a properly tensioned chain and a cleaned air filter. Adjusting the carburetor of the Champion chainsaw is carried out using three screws and is carried out in two stages: with the engine turned off and while it is running. First, the screws for maximum and minimum speed when stopping the engine are turned clockwise until they stop. And then, without stopping, turn the adjusting screws 1.5 turns in the opposite direction.
The second stage involves adjusting the idle speed while the engine is running. But, before proceeding to the second stage, you must initially thoroughly warm up the chainsaw engine for five minutes. And then, when stopping the engine at idle, slowly turn the adjusting screw clockwise. But as soon as the chain begins to move, you must immediately begin turning the screw in the opposite direction, counterclockwise.
For an inexperienced person, performing all these manipulations to correctly adjust the carburetor can cause certain difficulties. And therefore, it is better, after all, to turn to professionals, with the help of whom the carburetor will be quickly adjusted and the “Champion” chainsaw will be able to work without interruptions. Experienced specialists will not only help you adjust the carburetor, but will also tell you how to use the Champion chainsaw correctly.
Adviсe
Determination of cutting chain wear
Before each start of work, you should pay attention special attention on the appropriate sharpening rules and tension of the cutting chain. The chain tension is correct when the chain rests against the underside of the bar and can be easily turned by hand. To be able to do this, the chainsaw chain brake must be released.
A chainsaw chain requires sharpening in the following cases:
When sawdust produced when sawing wet wood looks like wood flour.
The chain enters the wood only when pressed firmly.
The cutting edge is noticeably damaged.
While sawing, the saw is pulled to the left or right. This is caused by uneven sharpening.
Timely determination and elimination of the wear level of a chainsaw chain is the key to long service life of the entire cutting set.
With your own hands
Instructions for running in chainsaws
Before using any imported chainsaw, it requires preliminary running-in. It is necessary, on the one hand, to extend the service life of the gasoline engine. During the running-in phase, the moving parts must first get used to each other, because Increased friction resistance is observed in the drive mechanism. On the other hand, during break-in you can acquire the necessary skills to work with a chainsaw. This is especially important for those who are working with a chainsaw for the first time.
When working with a chainsaw when preparing the fuel mixture, use only branded oils. The brands of oil that can be used to prepare the fuel mixture are indicated in the operating instructions. Observe strictly required proportions oil and gasoline. The octane number of the gasoline used must be at least 90 (except for those cases where this is specified in the operating instructions).
Before starting the chainsaw, be sure to check the presence of oil in the chain lubrication tank. At high speeds, in the absence of chain lubrication, the chain and tire may fail. During operation, you can easily check the presence of chain lubrication. With the chainsaw running at high speed, point the bar at a clean sheet of paper. If the lubricant flows normally, a strip of oil will be visible on the sheet.
Read the instructions carefully, those sections regarding starting a hot and cold engine. The principle of starting the engine is the same in all saws. The only differences can be in the location of the saw controls (STOP button, air damper lever). Remember to check the position of the inertia brake before each start. The inertia brake must be switched off. When the inertia brake is switched off, the chain on the bar is pulled freely by hand (this operation can only be carried out while wearing work gloves).
When operating a chainsaw with the inertial brake on, the chainsaw body melts in the clutch area and the chainsaw may catch fire. Repairs required in this case will be considered non-warranty and will be carried out solely at the expense of the client.
Run-in must be done within 3-4 hours. During break-in, it is prohibited to operate the chainsaw in idle mode for a long time. It is allowed to idle for 15-20 minutes with periodic gas release of the engine at intervals of 20-30 seconds. Then you need to continue running in operating mode with a light load. This involves sawing small-diameter wood with minimal effort on the part of the operator.
After running in the chainsaw, you must present it to service center for checking carburetor settings. Settings may only be carried out by a qualified technician. After setting up, you can use the power tool according to the operating instructions.
Characteristics
Technical parameters of saw chains
When choosing a chain for a chainsaw, you need to pay attention to several important characteristics:
- number of links;
- chain pitch;
- drive link thickness;
- purpose of use.
In addition, on our website you can select a chain according to your saw model through the chain saw directory.
Number of chain links. Determined by the internal teeth of the chain.
Chain pitch- the distance between three consecutive rivets, divided by two. This is a defining parameter, and depending on its value, all existing chains are divided into five groups with pitches of 1/4’’, 0.325’’, 3/8’’, 0.404’’ and 3/4’’.
The 1/4” (6.35 mm) pitch is typical for small chains installed on low-power one-handed saws.
0.325'' (8.25 mm) and 3/8'' (9.3 mm) pitch chains are the most common options. More than 80% of saws produced around the world are equipped with them.
Pitches of 0.404'' (10.26 mm) and 3/4'' (19.05 mm) feature chains with larger links and increased performance. For several decades they were equipped with saws Russian production, but are now installed only on powerful felling saws and harvesting equipment.
The larger the chain pitch, the larger the links that make it up and the higher its performance, but the wider the cut. To overcome the increasing cutting resistance, a more powerful saw is required. Fine pitch chains have other advantages - larger number teeth per unit length, smooth movement in the cut and, accordingly, reduced vibration, cleaner cut.
Drive link thickness. During operation, the chain slides in the groove of the bar, 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 eliminates the possibility of it “jumping off.” 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'') highly professional saws.
Purpose of use imposes its own requirements on the circuits used. For example, if it is necessary to saw hard and contaminated wood or during demolition and construction of structures, it is better to use special carbide chains Picco Duro or Rapid Duro, which have carbide teeth or linings, giving them unsurpassed strength and durability. Some jobs simply cannot be completed without their help.
It is also known that for longitudinal sawing wood (along the fibers), it is advisable to use special chains. The main difference between longitudinal and transverse type chains is the angles of attack cutting links. For crosscut chains they are 25–35 degrees. For rip sawing chains (e.g. Stihl chains Picco Micro X) angles are sharper - from 5 to 15 degrees.
The use of chains inappropriate for their purpose leads to either reduced performance or increased “aggressiveness”, strong vibration and additional load on the chainsaw engine.
Additional characteristics of the chain are profile height and cutting depth.
Profile height. Chains are available in high and low profile depending on the height of the cutting edge above the plane of the guide bar. High profile chains are usually used for professional purposes to achieve maximum sawing performance. Low-profile chains are installed on household and amateur chainsaws, because... Thanks to the increased support area of the cutting links and the reduced thickness of the cut chips, they are safer.
Depth of cut- this is the size of the gap between the upper edge of the tooth and the cut stop, which regulates 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 largely determines sawing performance. The larger the gap, the higher the performance. The downside to performance is vibration. So chains with a small depth of cut in the cut move more smoothly and “twitch” less. Therefore, to balance vibration and performance, cutters with a small depth of cut are often installed on a chain with a large pitch, and vice versa.
Prices / Order
| PETROL TOOLS | ||||
| BOSCH training 01/04/13. | ||||
| Mechanical lawn mower BOSCH AHM 38C (38cm, 5 blades, smooth adjustment 7kg) Germany 0600886102 | 3"545.00 rub. | pcs. | ||
| CHAMPION student 01/04/13 | ||||
| CHAINSAWS CHAMPION | ||||
| Chainsaw Champion 55 -18"- 0.325-1.3-72 in case (2.4 kW; 4.95 kg, easy start) pr. China S5518 | 5"370.00 rub. | pcs. | ||
| Chainsaw Champion 137-16" -3/8-1.3-56 (1.55 kW; 4.5 kg) pr. China S3716 | 3"490.00 rub. | pcs. | ||
| Chainsaw Champion 341-18"-3/8-1.3-62 (1.6 kW; 5.8 kg, easy start) pr. China AC3112B8TD-40-AO | 4"735.00 rub. | pcs. | ||
| CHAMPION PETROL TRIMERS | ||||
| Petrol trimmer CHAMPION T221 (0.5 kW, trimmer head, 4.5 kg) (PRC) T221 | 3"450.00 rub. | pcs. | ||
| Petrol trimmer CHAMPION T266 (detachable rod, 0.75 kW, trim head + knife, steering wheel handle, weight 5 kg) made in China T266 | 4"730.00 rub. | pcs. | ||
| Petrol trimmer CHAMPION T334FS (4-stroke 0.75 kW, 33.5 cm3, trim head + 3 blades, handlebar handle, 8 kg.) China CG335 | 6"950.00 rub. | pcs. | ||
| Petrol trimmer CHAMPION T436 (split shaft, 1.25 kW, trim head + 3 blades, handlebar handle, 8.9 kg) China T436 | 5"470.00 rub. | pcs. | ||
| Petrol trimmer CHAMPION T516 (1.46 kW, split shaft, trim head + 3 blades, handlebar handle, 9.5 kg) China T516 | 5"990.00 rub. | pcs. | ||
| Electric trimmer CHAMPION ET450 (450W, lower motor, 2 lines, 1.6 mm, width 350 mm, 3kg) China YT5243 | 1"640.00 ruble | pcs. | ||
| Electric trimmer CHAMPION ET1003A (1000 W, bent shaft, line 2.4mm, width 350mm, 4.1kg) China ET1003A | 2"390.00 rub. | pcs. | ||
| Electric trimmer CHAMPION ET1004A (1000 W, straight shaft, 2 lines, 2.4 mm, width 450 mm, 4 blades, 5.5 kg.) China ET1004A | 3"120.00 rub. | pcs. |
||
Firms
Review of popular models
For Russia, this country of logging, forests, forest industry; a great country in which the procurement of firewood for the bulk of the population is a constant, urgent need; countries where hobbies for gardening and wood processing are becoming widespread, chainsaws are of particular importance.
Traditionally, in order to understand the features of chainsaw models, we will focus on some frequently mentioned characteristics. All household chainsaws are intended for occasional work. These are, as a rule, low-power tools with the necessary minimum functions for a user who works with a saw occasionally and does not have professional skills in this area.
Semi-professional chainsaws are chainsaws with which you can perform any kind of work: repair and construction, felling forests. The “weak point” is the inability to use it for more than 8-10 hours daily. Such saws are often used as loppers in logging.
And professional chainsaws that have high power with a wide range of functionality. They are used in the form of shaft saws and can work up to 16 hours a day. Lightweight and low-power saws, convenient and simple, designed for household work and firewood preparation. These chainsaws are sometimes used professionally by loggers for tree limbing. There are also universal chainsaws - powerful for felling forests and easy for pruning. Signs: smooth, level bottom of the car; rounded corners; shortened, flat wheel cover; tubular inclined handle; anti-vibration system.
Prolonged work with a vibrating tool can lead to some serious diseases of your joints, therefore the presence of an anti-vibration system is important for professional models– this is necessary.
When set correctly, the chainsaw runs smoothly and should not emit excessive smoke as the engine speed increases. When the carburetor adjustment was initially set incorrectly, you will immediately notice clouds of smoke that may be released during operation. An incorrectly adjusted carburetor can shorten the life of the chainsaw. Learn how to adjust your Chinese chainsaw to ensure it runs smoothly and efficiently.
Setting up a Chinese chainsaw
The procedure can be challenging. Some models are made after the example of expensive and high-quality models produced by famous brands. For this reason, you can see it on some Chinese analogues.
- Idle Speed Screw - This adjusts the engine speed when idling. If it is set too low, the saw will not work. If you install high, you may run into problems with the chain. It's dangerous!
- The low speed adjustment screw is a low speed setting. This is an adjustment that controls the air/fuel mixture at idle. In the first case of incorrect adjustment, the saw will not start at idle. In the second case, engine failure will occur.
- High speed adjustment screw. This is a regulation that controls the air-fuel mixture at high speeds. Incorrect setting leads to high speed of the chainsaw.
Regulation rules
Step 1. Check the fuel level in the fuel tank. This tank should be half full. If there is less fuel, it will make proper carburetor adjustment more difficult.
Step 2. Gain access to the carburetor. The location may vary depending on the model and manufacturer of your specific chainsaw. Generally, you will need an adjustable wrench and a hex wrench to remove the bolts from the chainsaw body. Remove the housing. Carburetor adjustment will be made using small screws near the engine.
Step 3. Start the chainsaw and wait three minutes. This allows the engine to warm up, which is necessary for proper carburetor adjustment.
Step 4. Turn the idle speed adjustment screw. You will hear the engine spinning or slowing down as you turn the propeller. Set the engine to idle so it runs at high speed. This will help prevent the engine from switching off unintentionally.
Step 5. Turn the screw adjustment to low speed. Turn it to one side until the engine runs as strong as possible. Turn the screw the other way. Note the two positions of the auger and turn the screw so that it is halfway between these two points. Pull the chain saw a little to check how it operates at low speed.
Step 6. Pull the trigger to bring the chainsaw to full throttle. If the engine runs normally, the full speed adjustment screw is installed correctly. If the engine is acting up, adjust the screw and pull the trigger again. Repeat until the chainsaw is running at full speed without interruption.
Step 7 Reattach the chainsaw body.
The carburetor setting of a Chinese chainsaw affects the operation of the tool. If you notice a difference in your chainsaw's performance, or if it's starting to run rough, a tune-up can help. While newer units are designed to prevent adjustment by anyone other than a licensed professional, older models feature easy-to-use screws for quick adjustments.
Adjusting the high speed adjusting screw not only affects the power output, but also the high rotation speed. If the screw is turned too far clockwise, the permissible operating frequency will be exceeded. This can lead to engine damage caused by lack of lubrication and overheating, among others. Adjustments to the high speed adjuster screw setting can only be made if an accurate tachometer is available to check the maximum engine speed of 13,000 rpm (with the bar and the chain properly tensioned).
When an engine is factory checked, the carburetor is set to produce a rich mixture to ensure that the cylinder bore and bearings receive additional lubrication during the period of operation. The high speed adjustment screw may be turned no more than 1/4 turn clockwise.
Do you own a brand name? Husqvarna chainsaw 137? Then check out a similar article about.
Warning! The maximum permissible engine speed must not be exceeded! Please note that even minor changes to the adjusting screws have a noticeable effect on engine behavior.
Video: adjusting a Chinese chainsaw
In many private households, chainsaws are included in the standard set of household tools.
Models of different classes are used:
- for felling old trees;
- sawing fuel wood;
- construction of residential and commercial buildings;
- care of fruit and ornamental trees.
The lack of an established service forces owners of chainsaws to independently service their equipment, master rather complex adjustment and renovation work. Many users encounter problems with fine-tuning fuel equipment.
Full adjustment of a chainsaw carburetor requires knowledge of the design features of this model and a full understanding of the processes occurring in it. Only under these conditions can the engine be brought to optimal performance traction and economical fuel consumption.
With certain qualifications and appropriate equipment, the owner can flush and adjust the carburetor, as well as perform simple repairs at home.
The trial and error method in adjustment work is not acceptable. Moreover, unqualified intervention in the operation of the engine can seriously affect its performance and service life.
The task of adjusting the chainsaw carburetor is to supply fuel and air proportionally, in a ratio of 1:16, to the engine cylinder. This composition of the gasoline-air emulsion provides maximum speed and combustion temperature, maximum traction properties and torque reserve.
Properly done work has a positive effect on the productivity, efficiency and durability of the tool in difficult conditions. Timely and correct engine adjustment reduces the cost of maintaining a chainsaw and contributes to the low-cost development of its resources.
Characteristics of the quality of the mixture at the carburetor outlet
A working mixture is formed directly in the carburetor, the composition of which can be adjusted within a sufficient range of operational adjustments. When the power unit operates on a rich mixture, the fuel does not burn completely, as a result of which the thrust drops and the engine burns fuel with less efficiency.
Combustion of a lean mixture is characterized by engine overheating, a drop in power, deterioration of the lubricating properties of the oil component of the fuel mixture, and the appearance of detonation phenomena that are unsafe for the design of the power unit.
Factory settings of fuel equipment are made on the basis of average data that does not take into account the impact external factors, including air pressure and temperature, level of operating loads.
Periodic adjustment of the composition of the gasoline-air emulsion makes it possible to maintain the traction characteristics of the power drive at a given level and stabilize the economical consumption of fuel and motor oils.
Prerequisites for additional adjustments
Adjustment of fuel equipment is most often done when the octane number of the fuel changes or sudden temperature changes environment, the need for prolonged operation of the tool at high-speed operating modes.
Preliminary adjustment of the chainsaw carburetor at the break-in stage is duplicated by the final adjustment, which is recommended to be performed using test equipment from the service department. Standard equipment includes a visual indicator of mixture quality and a tachometer. After the instrument reaches operating mode, the adjustment performed at a professional level is considered to be fully implemented.
Self-tuning of a chainsaw carburetor in field conditions ineffective, and in some cases even unsafe.
Changes in power characteristics may be affected by:
- low quality or incomplete fuel supply;
- water getting into the carburetor;
- clogged jet or air intake filter clogged with sawdust.
Design features
Despite the possible difference in design, chainsaw carburetors operate on the same principle, so the adjustment sequence different models is not significantly different.
Prestigious chainsaws from leading manufacturers are equipped with technically advanced carburetors with built-in compensators and automatic choke control. Such modifications contribute to operator comfort, but do not affect fuel economy and other operating parameters.
Add to list additional equipment includes a booster pump designed to enrich the mixture before starting the power unit. Many models of professional-class chainsaws are equipped with carburetor heating devices, which are turned on when the tool is transferred to winter operation.
Preparation for self-tuning of fuel equipment
The sequence for adjusting the carburetor is outlined in the attached operating instructions. The factory kit includes a screwdriver for adjusting the screws marked with the letters L, H and T. Some manufacturers equip their chainsaws with carburetors, the adjustment of which requires a special adjustment key.
Correct tuning of the fuel system requires warming up the power unit to operating temperature and preliminary cleaning of the air intake filter element. The saw is installed in a position ensuring easy access to fuel equipment.
Adjustment sequence
Photo: tools for carburetor adjustment IN standard version Correct carburetor adjustment is done in stages. Basic adjustment is performed with the engine running, the second part of the work is after it has warmed up.
- Before starting adjustment, the maximum and minimum speed screws should be tightened all the way and unscrewed one and a half turns.
- The idle screw is set to the position of stable engine operation at minimum speed, at which the chain should not move.
- The throttle response of the engine is checked by sharply pressing the throttle. Without a loss of power, the engine should reach maximum mode in the minimum time, according to the tachometer up to 15,000 rpm. If there is no pickup, the screw with index L should be turned clockwise 1/8 of a turn.
Correct idle speed adjustment ensures stable speed when releasing the gas suddenly, and no movement of the unlocked chain.
Possible reasons for setup ineffectiveness
If the work performed did not give the desired result, the reason for the failure may be:
- unclear operation of the ignition system;
- clogging of the jets or reduction of their cross-section with resinous deposits, which can be removed by washing in acetone;
- When the carburetor threads are loosened, a gap may form through which air can leak.
After eliminating the detected deficiencies and malfunctions, it is recommended to repeat the carburetor adjustment in the standard sequence. If re-tuning is not effective, you must use the services of service specialists.
Unstable engine operation can also be caused by:
- air leakage through the crankshaft seals and seat cylinder;
- Poor sparking of the electronic ignition system cannot be ruled out.
Complex faults can only be fully eliminated if appropriate repair equipment is available.
Disassembling the carburetor
Repair of fuel equipment requires its disassembly. To access the carburetor, you need to remove the top cover and remove the filter foam pad. The drive and fuel hose are also disconnected.
The carburetor has small components in its design that can get lost. You can avoid the typical self-repair installation errors if components are laid out in groups and in the appropriate sequence.
Cleaning jets made of relatively soft metal with steel wire is prohibited. Scratches in the channels can negatively affect mixture formation. The performance of the jets is restored by washing in a clean solvent of the acetone group.
Damaged gaskets can be made from gasoline and oil resistant material, but to save time it is better to buy a repair kit.
Features of setting up fuel equipment for saws made in China
A significant part of Chinese chainsaw equipment is, to a greater or lesser extent, successful copies of models from European brands. Adjusting the carburetor of a Chinese chainsaw may have minor differences, which are indicated in the instruction manual.
- In the basic version, adjusting a standard Chinese carburetor begins with setting the idle speed. By rotating the screw, minimum stable speeds are set that do not allow movement saw chain on the bus.
- When switching to medium speed mode, the smoky exhaust is eliminated by turning the lean mixture screw. A significant increase in operating mode speed is possible, which is brought to the optimal level by the maximum adjustment screw.
- The maximum speed should not be higher than the value specified in the instructions. If there is no tachometer, the operating mode is set by ear. A properly tuned engine should pick up speed quickly and not stall when the gas is released to a minimum.
It is not recommended to operate the engine for long periods of time at high speeds without load or in idle mode. In the first case, the design of the connecting rod and crank mechanism is subjected to extreme loads, in the second, the loaded elements of the piston group operate under oil starvation conditions.
The operation of a chainsaw engine is based on the combustion of a special mixture, which consists of fuel, oil and air. To prepare such a mixture and evenly transfer it to the combustion chamber, the engine has a special device - a carburetor.
The design of the saw includes a device that has factory settings. As the device is used, these settings become lost, and the carburetor must be adjusted again. To understand how to adjust a chainsaw carburetor, you need to know what parts the device consists of and how it works.
The design and principle of operation of the carburetor
Let's find out the structure of the chainsaw carburetor. This device consists of:
- housings;
- diffuser, which is located at the entrance to the device;
- jets;
- valves regulating the supply of the mixture;
- special sprayer;
- float chamber.
The device has 2 or 3 adjusting screws equipped with springs. At the end of the screws there are needle-cones.
The principle of operation of a chainsaw carburetor:
- When the engine is turned on, the air damper opens.
- The air moves forward and mixes with the fuel in the diffuser, where the passage narrows.
- The air flows through the jets, then is cleaned by a filter and enters through a damper located at the diffuser inlet.
- In this case, a special damper, which is located behind the diffuser, distributes the mixture, and it enters the combustion chamber.
The device is designed in such a way that the volume of fuel that passes through the jets is regulated by the chainsaw bolts. The volume of fuel in the chamber depends on the valve with a sharp cone. The operation of this valve is regulated by a membrane that controls the flow of mixture into the chamber. The operation of these components depends on the rotation of the internal combustion engine. The mixture is purified using a filter.
When adjustment is needed
Carburetor adjustment must be performed:
- If the settings are lost due to loose screws or vibration, or when trying to adjust the device.
- If the housing cover is broken.
- To find out the reasons why the design does not work.
- When the engine does not turn on or runs with effort, and then immediately dies out.
- When a chainsaw shoots into the carburetor or “sneezes.”
- The chainsaw vibrates a lot.
- To check why there was excessive fuel consumption.
- When thick exhaust appears.
- If the device does not receive gasoline.
- When the spark plugs are blackened or coated.
- The saw cannot operate at high speeds and increase power.
- Check the engine if it turns off when revving up.
- The operation of the air purification units was disrupted.
- Debris has entered the mixture distribution system.
- The pistons have worn out.
Adjustments also need to be made when changing the fuel brand and changes in humidity.
How to set up
Setting up a chainsaw carburetor is done as follows. Before adjusting the carburetor on a chainsaw, you should find out whether all filters are clean. The device is adjusted with three bolts:
- main jet H;
- idling L;
- idle adjustment S (some manufacturers call it LA or T).
- The tool is installed on the workbench so that it is in a stable position.
- The device circuit must be directed away from you.
- There must be at least 2 m between the instrument and other objects in the room.
It is important to know how adjustments occur when the structure malfunctions. Turn on the carburetor and wait 10 minutes. The adjustment begins by finding the location of screw L at which the idle speed will be high. You need a wrench to adjust the bolts. Gradually turn the bolt, first in one direction, then in the other, until the correct position is reached. Then turn the screw 1/8-1/4 turn counterclockwise. Then the idle speed is corrected with screw S (or T, LA).
If after tightening the needle bolt L the chain does not move, then gradually turn the screw S clockwise until the chain begins to move. Then adjust S 1/8-1/4 turn back. If the chain moves, turn screw S counterclockwise until it tightens. Next we twist S by 1/8-1/4 turn in the same direction.
The internal combustion engine must function smoothly. You should also check how it accelerates. If you press the accelerator, the speed should increase to maximum. This means that the engine spins well.
Finally, the operation of the device at idle is tested. When the adjustment is made correctly, the design should not work like this:
- The chain is motionless.
- The sound of an internal combustion engine is similar to that of a 4-stroke generator.
- If you press the accelerator, a rapid spin will occur.
If these requirements are not met, then the idle speed must be adjusted. To do this, tighten screw S as described earlier. If this does not help, you should repeat the adjustment from the beginning.
That's what they do manual setting. Fine adjustment is carried out using a tachometer device. All actions are the same, only the screws are turned based on tachometer data. Thanks to this device, the carburetor can be adjusted faster.
Malfunctions and their elimination
Repairing a chainsaw carburetor with your own hands allows you to eliminate all problems that arise during the operation of the device.
If the internal combustion engine spins intermittently and accelerates for a long time, then you need to tighten L counterclockwise by 1/8 of a turn. Then adjust bolt S again. These adjustments should be made until the motor functions correctly and accelerates quickly.
Then check the setting of screw H. Accelerate the motor to maximum. Watch the exhaust and how the engine spins. If blue smoke comes out of it and the saw makes a loud noise, then this means that the carburetor is creating a mixture that is too rich. The highest engine speed is less than normal. Soot forms in it. In case of such a problem, you need to turn H a little clockwise. Then they control the operation of the motor and, if necessary, repeat the setting.
If the saw squeals, this means that the engine is overheating, the exhaust is crackling, and there are misfires. This means that the mixture is unsaturated, and the highest engine speeds are higher than normal. This leads to overheating of the engine, combustion of the piston, cylinder and burnout of the spark plug. If this problem occurs, adjustment should be made by turning H 1/4 turn counterclockwise.
If fuel does not flow into the combustion chamber, this problem is caused by a clogged fuel filter, nozzles or device channels. To eliminate the malfunction, you will need to completely disassemble the filter and blow through these channels using a compressor. Carburetor fluid is used to clean the channels.
It happens that there is an overflow of fuel in the carburetor. This happens if the membrane has failed, dried out and become rough, and began to put pressure on the rocker arm attached to the needle. Then the needle is adjusted. To change the membrane, you need to remove the carburetor.
The motor runs intermittently and does not pick up speed well. This happens when the filter is clogged. It is necessary to remove the cover of the device and clean it using detergents.
How to remove a carburetor
Before repairing or cleaning the carburetor, it must be dismantled and disconnected from other systems. Dismantling the carburetor is carried out as follows:
- Remove the top cover. To do this, you need to unscrew the bolts (3 pieces) that are located around the perimeter of the cover.
- Remove the carburetor filter.
- Then disconnect the gasoline supply hose.
- Disconnect the motor drive traction.
- Unscrew the cable connection end.
- Carefully remove and pull out the gasoline supply hose.
DIY disassembly
Disassembling the Homelite chainsaw carburetor is carried out as follows. Prepare a place - a flat surface. You will need the following tools:
- set of screwdrivers and wrenches;
- detergent composition;
- ultrasonic bath for cavitation;
- a large piece of cardboard.
After you have removed the carburetor, you should disassemble it. Disassembly of the carburetor is carried out in the order provided for by the design of the device.
The parts of the device are small, so they should be folded in order, making sure that no components are lost.
After disassembly, the device is troubleshooted and non-working parts and components are replaced. Wash the device with a special liquid, dry it, and wipe with a dry cloth. Blow out the tubes and jets with compressed air. Before this, they are treated with ultrasound to remove plaque.
How to clean
When doing the work yourself, you need to know approximately how to clean and flush the carburetor. Wash the device as follows:
- Unscrew the screws on the device body.
- Open the lid, take out small parts and lay them out on the fabric.
- The walls of the device and all parts are treated with air from the compressor.
- If carbon deposits remain on the components, they are wiped with a degreaser.
- The components and body are dried.
- Assemble all the carburetor components and install it on the chainsaw.
It is necessary to flush the carburetor if low-quality gasoline was used to refuel it or if a chainsaw was used in severe frost. After cleaning, the engine will work better and the chainsaw will spin up faster.
