Repair your chainsaw yourself

Repair your chainsaw yourself


Chainsaws are available on the premises of almost every villager and many owners of summer cottages. They are easy to use and can be repaired by yourself. Find out the reason why the device does not start, triples, has problems with idling, not so difficult. Despite the varieties of chainsaws, the principles of repair are the same.


  • 1Types of chainsaw
  • 2What you need to troubleshoot
  • 3Malfunctions and repair by own hands
    • 3.1Ignition system (does not start, stalls)
    • 3.2Fuel supply system
    • 3.3Debris and cleaning the muffler
      • 3.3.1How to remove and clean the muffler on the chainsaw
    • 3.4Cylinder-piston group
      • 3.4.1How to measure a compression by a manometer
    • 3.5Chain, tire
    • 3.6Chainsaw leading sprocket
      • 3.6.1Replacing the main sprocket chain saw
    • 3.7Chain lubrication system
    • 3.8Chain brake

Types of chainsaw

Chainsaws are divided into classes and purpose.

Chainsaw classes:

  1. Household. These saws are used in everyday life. For example, for harvesting firewood, sawing boards. A household saw can cut down branches and trees of small thickness. The tool has a minimum of functions, low power and weight up to 4 kg. Household saws are the cheapest and are not designed for long work. Recommended use is up to 20 hours per month, that is 40 minutes a day. Such saws may well be used by women and elderly people.
  2. Semi-professional. They are used for making trees and construction work. They are often purchased for professional use, for example, employees of greening firms. But even in the home such saws can be used due to the dimensions and weight smaller than that of a professional tool. Specifications and price are between household saws and professional. The disadvantage of these saws is that you can not work for 10 hours continuously. It is necessary to make large intervals.
  3. Professional. Such saws have all the necessary functions, high power up to 6400 W, large sizes and weights. They are used by communal and rescue services, but the main application they found in loggers. After all, such a powerful tool can cut down trees with a diameter of more than 70 cm and work 8-10 hours without breaks. Professional chainsaws serve for years. They have the most reliable piston system, chrome-plated cylinders. The resource of work is 3 times more than household models. Accordingly, the price of such a tool is the highest.

The purpose of the tool affects the power, weight and dimensions. Chainsaws have three purposes:

  1. The garden.
  2. Farmers.
  3. Felling.

What you need to troubleshoot

Before starting the analysis and repair of chainsaw, prepare the necessary tools and accessories:

  1. Overalls.
  2. Gloves.
  3. Free space on the table.
  4. Candle wrench with screwdriver.
    Candle wrench with screwdriver
  5. Screwdriver for adjusting the carburetor.
    Screwdriver for adjusting the carburetor
  6. Hexagon key.
    Hexagon with T-handle
  7. Socket wrench.
    Socket wrench
  8. Manometer for measuring the compression.
    Manometer for measuring the compression
  9. Piston stop for two-stroke engines.
    Piston stop for two-stroke engines
  10. Removable coupling clutch for chainsaw.
    Sleeve clutch for chainsaw

Malfunctions and repair by own hands


Chainsaw problems can be of two types:

  1. Malfunctions of the engine, ignition system, fuel supply and exhaust.
  2. Malfunctions of other nodes.

The following indicators will indicate that it is necessary to carry out engine diagnostics:

  • The tool does not start or starts and stalls.
  • It works unstably.
  • At idle runs, and when the load falls or turns stall.

Other node problems:

  • Problems of the lubrication system.
  • The chain brake does not work.
  • Breakage or chain production.
  • The asterisk worn out.

Ignition system (does not start, stalls)

It is necessary to check the appearance of the spark plug.

  • Take the candle key. Remove the insulating cap with the power cable. Use the key to unscrew the candle.
    Location of the spark plug
  • If it is dry, then the ignition has nothing to do with it. Screw it back and go to the fuel supply diagnosis.
  • If the plug is flooded with fuel, the rules of starting the engine are incorrectly observed or the carburettor is poorly adjusted. Dry and burn the candle. Now you need to remove excess fuel. Pull the starter 15-20 times. Tighten the candle. Put on the cable. Try to start a saw.
  • A lot of carbon was formed on the candle. This trouble appears in three cases: wrong proportions of gasoline and oil in the fuel mixture, poor oil, improper adjustment of the carburetor. To get rid of the formed deposit, burn the candle well. Take the metal brush and remove the scum. Strip the candle with fine-grained sandpaper and needle, then screw back.
    Spark plug with carbon black
  • Always check the clearance between the center and side electrodes of the candle. It should be, 5 mm.
  • Look at the condition of the gasket. It prevents air from entering the combustion chamber.
  • Now we need to check the appearance of the spark. Put a power cable on the plug and attach it with a thread to the cylinder. Pull the starter. If there is no spark, replace the spark plug. Check the new one in the same way. If it does not have a spark, the power wire is defective. Replace it.
    Check for a spark in the spark plug

Fuel supply system

Fuel is not supplied for three reasons:

  1. There is a hole in the fuel tank cap that could be clogged. If this happened, a vacuum formed, which prevents the fuel from escaping.
  2. A fuel filter is installed in the tank. It eventually becomes dirty.
  3. Fuel is poorly fed from the carburetor into the cylinder.

The first two reasons are revealed identically. For this, it is necessary to detach the hose through which the fuel passes from the carburetor. And check with what pressure it flows. If it is weak or does not flow at all, then the tank cap is cleaned with a needle, and the fuel filter is replaced. But first you need to drain the fuel mixture and pull the filter out of the tank with a wire hook. If the fuel flows well from the disconnected hose, the air filter is clogged or the carburetor is defective. The air filter affects the intake of air into the carburetor and the enrichment of the fuel mixture. When it is clogged, the mixture is too enriched, since air does not flow. This affects the proper functioning of the engine.

  • Carefully remove the air filter so that the dust does not scatter. Cover the hole formed in the combustion chamber with a clean cloth.
  • Purge the filter and clean with a soft brush. If the filter is not cleaned, flush it. After drying, put it back.

Before you start adjusting the carburetor, check the cleanliness of the air filter and whether the chain is tight enough. Read the instructions. The manufacturer describes how to properly adjust the carburetor. If no instructions, find the three marked screws:

  1. H - maximum speed screw.
  2. L - the screw of the minimum turns.
  3. S - the screw of exact adjustment of turns of idling.
    Screws for adjusting the carburetor

Take the screwdriver to adjust the carburetor and proceed.

  • Basic adjustment.It is produced when the engine is cold. Turn the screws H and L all the way to the right, that is, clockwise. Then one and a half turn to the left.
  • Idle speed adjustment.Before starting, start and warm up the engine. Rotating the screw S to the right increases the speed, and lowers it to the left. You need to lower the speed and control, so that the engine will work stably, without pauses. Watch for the motionless chain. If the engine suddenly stops, gradually increase the speed. And when the chain moves, reduce.
  • Check the engine for acceleration.Press the fuel feed button gently. Adjusted engine must quickly and confidently gain momentum to the maximum. If the engine is late and does not work well, turn screw L to the left no more than an eighth turn.
  • Adjustment of the maximum revolutions.When the maximum speed is reached, there are interruptions in the ignition. Slowly turn screw H to the left until stability appears.
  • After all adjustments, check that the engine is idling.It must work stably when the chain is stationary. If you do not achieve the desired result, repeat all adjustments, except the basic one.

Debris and cleaning the muffler

When the silencer is clogged, there is nowhere for waste gases to disappear. The saw will not work and start. The design of the chainsaw allows you to remove the silencer quickly. Depending on the method of attachment, you may need a hexagon or socket wrench.

  • Unscrew the screws. Slightly swinging the muffler, remove it from the pins. The hole in the engine should be plugged with a clean cloth.
    Chainsaw Muffler
  • Burnt out the muffler, and the dirty must be cleaned.
  • Disassemble it.
  • Wash off the carbon. Dry cleaning of the silencer is prohibited, since the dirt it is clogged has carcinogens. And they can not be inhaled.
  • Dry the pure muffler.
  • Clean the cleaned or new muffler gently on the studs and push it in. Screw the screws.

The muffler is contaminated due to poor quality oil or improper fuel mixture.

How to remove and clean the muffler on the chainsaw

Cylinder-piston group


Wear and damage to the cylinder-piston group lead to the inability to start the engine.

Damaged piston

Damaged piston

To detect damage, remove the muffler. You will open the exhaust port, in which you will see part of the surface of the cylinder.

Part of the cylinder in the exhaust port

Part of the cylinder in the exhaust port

In addition to the piston, which may not have damage visible in this hole, inspect the piston ring. If the defects are present, then it is necessary to disassemble the entire piston group in order to fully assess its state. Faults are eliminated only by a complete replacement of the group.

Measure the compression:

  • Take a manometer to measure the compression. Tighten into the candle hole, gently pressing the rubber band.
  • Tear the starter, observing the arrow of the device.
  • The pressure should be at least 8 atmospheres.

If there is no such device, try the folk way. Unscrew the spark plug.

Compression check by folk way

Compression check by folk way

Plug your finger a candle hole and pull the starter. If the finger sucks, then there is compression.

How to measure a compression by a manometer

Chain, tire

Symptoms of chain wear:

  1. Violation of the integrity of cutting elements.

  2. Slots, fraying and cracks in the rivets and lateral sides of the links.

  3. The cutting link was worn out so that it was difficult to saw.

  4. The connecting link is damaged.

After replacing the 3 chains, change the tire and the drive sprocket.


Chainsaw leading sprocket

To replace the asterisk you will need: a spark plug, a piston stop, a clutch release.

  • Remove the lid to access the candle. Unscrew the key with a key.
  • With the clutch puller, rotate the clutch clockwise until the piston has risen to the top dead center. Through the candle hole, this can be checked.
  • Tighten the stopper of the piston instead of the candle. If it is not, then twist a thick bundle of ropes and insert it into the candle hole.
  • Turn the puller clutch to the right and you unscrew it.
  • Remove in sequence all details of the coupling assembly and a plate with an asterisk. Replace it with a new one.
    Chainsaw leading sprocket
  • Gather everything back.

Replacing the main sprocket chain saw


Chain lubrication system

If the tire is not lubricated or is poorly supplied, the chain and the tire overheat, there is severe friction and wear. Check the holes and channels for grease. If they are clogged, they must be cleaned.

Lubrication chain

Lubrication chain

Oil leaks if:

  1. On the body of the oil pump there are cracks. In this case, the pump must be replaced.
  2. Leaky connection of pump and tube.
  3. The tube is cracked.

On all chainsaws there is an oil flow adjustment. Near the location of the adjusting screw on the body there is always a marking in the form of a chain link and a drop of oil. If you turn to the right, the oil supply will decrease. For the winter, the supply of oil is increased, for the summer they are reduced. Strongly can not be reduced, because the tire will burn.

Chain brake

The brake stops working for the following reasons:

  1. Fusing the brake cover. Replace the lid.
    Fusing the brake cover
  2. Over time, the space under the brake cover becomes clogged. Clear clogs.
  3. Wear of brake tape. Replace the ribbon.

Chainsaws need regular cleaning of sawdust, dust, dirt, sludge and replacement of spare parts. If you can do this with your own hands, you will save time and money.

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