When Starting A Chainsaw The Chain Spins

A chainsaw in the country, in a private house. a common occurrence. She can be amateur, semi-professional and professional. The choice depends on the frequency and complexity of the activity. It greatly simplifies the work of harvesting firewood, helps to quickly put the log house. In the event of a breakdown, in most cases it is possible to repair the chainsaw with your own hands. Equipment failure may be associated with idle problems, the mechanism will not start or troit.

When Starting A Chainsaw The Chain Spins

The repair principle for all chainsaws is about the same. Before work, be sure to read the instructions. For this type of equipment, the great difficulty is not the repair itself, but the search for the source of damage.

What could be the problems

All problems can be divided into two large groups:

  1. Malfunction in the engine, combustion chamber, fuel and exhaust system.
  2. Damage to other nodes.

For engine failure, the following is characteristic:

  • equipment does not start, stalls;
  • does not pump fuel into the primer;
  • unstable work, floating speed;
  • works at idle, at loading it can float, stall, shoot.

If the problem is in other nodes, the following phenomena are noted:

  • poor lubrication;
  • the brake circuit does not work;
  • chain wear or breakage;
  • wear on the drive sprocket.

Main chainsaw malfunctions: causes

Every year, manufacturers develop equipment that is more complex and more reliable in design, but simple to operate. Chainsaws are no exception. But no matter what modern functions are included in the device, it is difficult to avoid a chainsaw malfunction. Diagnosis of breakdowns can be carried out independently, using the instruction manual. Consider the main types of faults encountered.

Saws crookedly

We will understand the reasons why the chainsaw is sawing crookedly. This is manifested during the cut under load of the trunks, when the tire gradually leads to the side. This is especially noticeable when sawing a wide trunk using the double cut method, first from above, then from below. As a result, the output is an uneven sawn surface, which in some cases is unacceptable. An example is the trimming of bars.

  1. Uneven sharpening of the teeth of the saw. This is the most common reason why the device obliquely saws the device. The teeth should be ground at the same distance to avoid sawing problems. The best solution is to purchase a grinding machine that adjusts to the most worn tooth of the saw mechanism. Or contact the workshop where there is such equipment. The result is all teeth of the same size.
  2. The circuit or bus used is not suitable for the parameters. When buying these items, you must consider the width of the groove. This is important not only for the correct operation of the equipment, but also for safety when cutting.
  3. The saw headset is very worn. If the device does not cut well, increased headset wear is possible. A visual inspection will indicate a problem. If the right or left side of the tire is worn out more, it must be replaced with a new one. With increased wear it makes sense to conduct a complete diagnosis of the lubrication system. This often causes increased wear on one side of the chain.

In case of complex repairs, it is better to return the equipment to a specialized workshop.


If a new chainsaw heats up, this is due to the fact that the elements of the piston group have not yet been rubbed. In this case, it is necessary to run-in, avoiding overheating. If the problem is with an existing device, the cause may be late ignition. Sometimes the device overheats due to a violation of the proportions of the preparation of the combustible mixture.

Not gaining momentum

The problem appears at startup. A chainsaw does not develop revolutions, runs jerkily or idle, stalls, starts up with a pusher, and beats back when starting up.

  1. If the device does not maintain idle speed, the reasons may be a blockage in the filter, poor-quality combustible mixture, carburetor, incendiary module or deformation of motor elements under load.
  2. If the saw does not develop traction at full power, pay attention to the carburetor. There is a possibility that the settings of the work node are set incorrectly. Adjust the “H” nozzle, which is responsible for cutting under load. To do this, set the fuel supply at high speed.
  3. Does not slow down. The problem is that the device can quickly develop speed at high speeds and not take off it. It is necessary to check the operation of the throttle, the switch of the toggle switch, the presence of a corkscrew on the throttle shaft.
  4. Uncontrollably gaining speed. The reasons may be in the carburetor, fuel supply system, connecting elements leading to the carburetor.
  5. The technique works only on the choke. The reason is improper preparation of the fuel mixture, a large amount of oil.

These are the main, most common causes of this type of problem.

Oil is flowing

Owners of chainsaws often encounter a problem when oil flows from below the unit. The reason lies in the damaged oil hose, which is connected to the pump.

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No spark

Problems with ignition are associated with a weak spark on a chainsaw or with its absence. When checking the spark plug, there may be a blue spark. This suggests that everything is in order. If spark is gone, check high voltage cable. It may have a wire break. Another option, why there is no spark, is due to an incorrect clearance between the ignition module and the flywheel magnetic circuit. The norm for this indicator is 0.2 mm.

No gas

To find the source of a breakdown and determine why the device is not pumping gas, disconnect the gas line from the carburetor. Try to pump fuel. If it is fed slowly, problems can be:

  • in the fuel filter, its clogging with garbage;
  • in the contamination of the gas supply channel.

Specialists do not fill the tank to the brim. This may damage the device.


If the equipment smokes, its power drops, pay attention to the engine. An unstable start, overheating can also indicate its breakdown.

The circuit idles

If the chainsaw chains are idling, this may be due to the following factors:

  1. The clutch spring burst. Visual signs: the chain spins almost always, even with an unstable engine start.
  2. A piece of clutch broke, the spring flew off. Signs: the chainsaw itself is gaining momentum, extraneous sounds are heard.
  3. Clutch wear. Symptoms: frequent slipping of the chain mechanism.

Idle operation of the saw headset is associated with clutch problems.

How to repair a chainsaw

When the causes of the breakdown are diagnosed, the operating instructions are studied, you can proceed to repair the chainsaw yourself. To do this, you need to disassemble the chainsaw, remove the damaged element or repair it, if there are solutions without replacement. When buying parts for a tool, pay attention to the characteristics, sizes, and other parameters that must match for reliable operation of the device.

How to disassemble

For analysis, it is worth familiarizing yourself with the main details and groups of the device, including:

  • engine;
  • clutch;
  • chain mechanism;
  • brake system;
  • chain catcher;
  • oil pump.

Circuits may vary depending on the manufacturer. Some mount the engine vertically, others horizontally. The most complex device for professional tools. To repair it, you will need original spare parts, which are quite expensive.

Before disassembling, ensure that you have all the tools and spare parts.

For example, to remove the chainsaw engine, you will need special pullers, keys. Making them yourself is time consuming. The problem is that repair information in full for foreign units is difficult to find. It will be good if you can find a disassembly scheme. Sequencing:

  1. We dismantle the saw headset. We drain fuel and oil from tanks, remove pollution from hard-to-reach places of the product.
  2. Dismantling a chainsaw requires special care when working with a carburetor. Many small parts are carefully removed and folded onto a white sheet of paper. Accessories are washed and assembled in the reverse order.
  3. Dismantling the piston group. It is necessary to remove the threaded fasteners, turn the saw on its side.
  4. Starting device. Worn parts must be replaced. One branded tire generates its resource through 3 saw chains.

All work should be carried out carefully, remembering where to put the part.

How to eliminate oil leak

  1. Remove the clutch mechanism from the shaft.
  2. Get the wire from the landing site. To do this, take pliers and pull on the outside of the hose.
  3. Wipe the rubber plug at the end of the hose from oil.
  4. Seat the seat with automotive sealant or special tape.
  5. Insert the hose into place, seal the plug with a flat screwdriver.

Repairing an oil hose is a simple operation feasible for everyone.

Piston replacement

Algorithm for replacing and installing the piston:

  1. Prepare a hammer, a candle wrench, a large flat screwdriver, a set of socket and open-end wrenches, a compressor for cleaning components.
  2. Remove the upper protective cover.
  3. Unscrew spark plugs.
  4. Remove the side cover.
  5. Remove the stopper from the shock absorbers.
  6. We fix the crankshaft using a lace, unscrew the clutch and the flywheel nut.
  7. We remove the leading chain sprocket.
  8. Remove the carburetor, ignition module and exhaust system.

After that, the piston mechanism can be removed.

Other repairs

Among other breakdowns, there may be a broken chain. If the reason is not a foreign object, perhaps the manufacturer uses low-quality metal. The chain may break due to overheating due to poor lubrication.

If the chain does not turn, does not pull, wedges, check if you removed the brake after starting the engine. In some cases, a replacement headset is required after this.

Poor saw quality can cause the chain to blunt quickly. It is better to change it for high-quality, branded components.

During operation, it happens that the circuit does not stop. There can be 2 options:

  1. Brake tape contamination. Dirt, dust, sawdust can get into the mechanism. This causes the brake to lock, the unit does not stop when the gas is released. Cleaning the unit will eliminate this problem.
  2. Wear on the brake band. Replacement required.

If the drive sprocket is worn, the chain wedges. This happens under load. Without it, the chain mechanism simply does not move.

Natural wear of spare parts is not uncommon. These include the drive sprocket, chain, tire, components of the anti-vibration system. It is important to monitor and timely replace such elements; their breakdown may adversely affect the more expensive mechanisms of the device. Due to the worn drive sprocket and tire, increased vibration strongly affects the crankshaft bearings, leading to failure. Wear 3-4 chains suggests that it is time to think about a new tire. It is subjected to increased exploitation from the bottom.

How to assemble

After all repairs have been completed, the quality of the reassembly is of great importance. Improper positioning of the part can lead to damage to the equipment and be unsafe for humans.

  1. The most important part is the assembly of the saw headset. It is better to make it in protective gloves to avoid cuts from asterisks. When installing the chain on the tire, pay attention to the direction of the edge of the teeth. She should go forward, on top of the tire. Place the gear on the drive sprocket. Return the clutch cover, tighten the nuts.
  2. Use a special key to tension the chain. The quality of this work affects the safety and operational efficiency of equipment in the future. A poorly tensioned chain will fly off, and a tight tension threatens with rapid wear. The chain can be raised no more than 1 cm above the tire. Check rotation and tighten nuts.

Any repair work of complex equipment should be carried out carefully. It is better to use original spare parts for this. Other options may adversely affect the life of the device. If you are not sure that you can manage it yourself, it is better to contact a specialized workshop.

This is especially applicable for expensive professional equipment. Incorrectly made repairs can lead to failure of the entire mechanism. To prevent breakdowns, try to comply with the requirements of the operating instructions, service the tool on time, follow the mechanisms, use high-quality oil and fuel, replace wear parts.