Why the chainsaw stalls

There are a lot of situations why a chainsaw stalls. As it is a technical mechanism, then at the slightest deviation it is characteristic to give a reaction through a partial or global failure. There is a list of the most common malfunctions, the causes of which we will consider in this article:

  • The machine shuts down straight away. To start the tool fully, the reason. in the details of the unit, which take part in the beginning of the tool.
  • When the load. There is a problem in the fuel system or air filter, because the pressure on all components of the tool increases manyfold.
  • When tilting. The fuel tube is in the air when the fuel tank is on the side, not in the fuel mixture.
  • At high revs. The problem may concern three parts: fuel pump, gasoline filter and air filter. The filters need to be flushed and cleaned and the fuel pump should not leak. Otherwise it must be replaced with a new one by a Kosi Kosa store.


With us you can also choose other spare parts for chain saws, we are happy to answer all your questions and prompt possible solutions to problems even in hopeless situations with the tool.

Chainsaw won’t idle. how to find and fix it?

The most common cause of this frequent failure is a wrongly adjusted choke. It is needed to draw in air, which the carburetor needs to enrich the fuel mixture with air. To adjust the choke, you need to adjust the carburetor. You need to pay special attention to the power unit’s idle speed. To check engine operation in idle mode, pay attention to the condition of the circuit immediately after starting the engine. If it is spinning, you will need to adjust the powertrain.

Another reason for this common problem is air intake. If one of the chainsaw’s mechanisms leaks air, the mixture will be automatically depleted, resulting in spontaneous increase of the chainsaw’s engine speed. In this case, the operator will need to carefully check the entire fuel system, including the carburetor, pipes, working chambers of the unit.

In some cases the chainsaw does not decelerate because the throttle cable is jammed. This will cause the power unit to rev to its maximum rpm immediately upon starting. The problem can be solved by disassembling the gas handle and inspecting the whole gas feed mechanism. A trapped cable needs to be adjusted or needs to be completely replaced.

Saw starter

The starter mechanism consists of a drum (1) with a cable (2) and a handle (3), and from a frame (4) with a returnable spring. When suddenly pulling the handle upward, the ratchet of the drum engages with the teeth on the motor shaft and turns the crankshaft. Where is the breather plug on a chainsaw?? All chainsaw malfunctions can be divided into what malfunction is the breather and. When releasing the handle, a returnable spring returns it to its starting position.

In order to turn the crankshaft at the speed at which the engine starts, it requires a certain amount of force. It is often not possible to start the chainsaw with the 1st jerk, you have to pull it a couple of times. To facilitate starting, different methods are used. enriching the fuel consistency with the help of the carburetor choke, or reducing the cylinder pressure with a decompression valve (to facilitate cranking the crankshaft).

The main and more complex chain links are the cutting links, which are divided into right-hand and left-hand. The top edge of the tooth is the widest of all parts. It provides a wide kerf that prevents other links from jamming.

A major cause of malfunction is a broken cord. It is necessary to remove the cover of the saw, unscrew the 4 screws that hold the starter motor. It is not difficult to change the cord. Check the condition of the rest of the starter motor immediately. Before you assemble, lubricate the moving elements and clean from dirt, oil leaks. The entire starter can be replaced.

Oil and gasoline ratio for STIHL 180 chain saw

Before you start working with the German STIHL MS 180, you need to fill it up. It is important to observe the amount of gasoline and engine oil you use. As stated in the factory instruction, to mix the fuel should be adhered to the proportion of 1:50, ie, in 50 parts gasoline need to stir 1 part of the oil. That means you only need 20 ml or less of oil in 1 liter of fuel.

The quality of fuel and oil is also important. The manufacturer recommends that you fill the STIHL MS 180 with at least 90 grade octane gasoline. STIHL 2-stroke engine oil is the correct lubricant.

Running in the STIHL MC 180 chain saw

After preparing the fuel and oil mixture you need for the first time you need to run in the new STIHL machine. This procedure is very important because all the working parts of the machine move into place and are precisely lapped up.

To run-in a STIHL 180 chain saw you need to proceed one after the other in the following steps:

stihl, chain, cuts, idle
  • First you need to add the fuel mix and a suitable oil for the chain lubrication. For this purpose, the device of the saw has separate tanks;
  • Next, the factory inertia brake should be turned off. this will prevent the plastic housing in the clutch area from melting;
  • After that you should switch the chainsaw on and let it run at idle speed for about 15-20 minutes;
  • Then it’s time to start cutting thinner branches. Gradually increase the thickness of the branches.
stihl, chain, cuts, idle

When running in the STIHL MS 180 it is important not to run the engine as fast as possible, because this can cause burrs on the cylinder surface. Also during the running-in period it is not recommended to use power drills, bark cutters and other common chain saw attachments.

What to do if the chainsaw picks up its own speed?

This fault is typical of beginning gardeners who neglect to service their power tools in good time. In case of random rpm increase with a chainsaw the reason is in the carburetor. First of all, it will need to be completely disassembled. After making sure that all built-in parts are in order, you can start flushing the fuel unit. To do this you need:

  • Put all the carburetor parts in a container with clean gasoline. After knocking the parts must be removed, rinse them thoroughly with water and dry them;
  • the fuel pipes should be blown out with compressed air from a container. Immediately before installing the hoses back in the places where they are connected to the fittings will be required to apply silicone sealant;
  • After installing the carburetor not the chainsaw, it is necessary to re-adjust it. Before that make sure that the power unit is in good condition and the filters, rubber gaskets and bushings are in good working condition.

In some cases, the cause of random revolutions of the chainsaw can be a loss of sealing of the crankshaft oil seal. Because of the constant contact with the moving shaft, the packing succumbs to increased heat, which leads to the formation of cracks and holes inside it. A damaged gasket cannot be repaired, so it must be replaced.

Often the cause of air drainage, which results in arbitrary revolutions of the engine, is the loss of fixation of bolt connections. In this case, the operator will need to tighten all the bolts and check the operation of the power tool again.

Elimination of fuel equipment failures

A simple analysis of the failures and malfunctions shows that most of them are caused by improper adjustment of the fuel system. A closer look reveals that the causes of the situation when the engine does not start, does not pick up speed and stops are almost the same.

In most cases this is:

  • air drainage due to loose screw fasteners or destruction of the crankshaft oil seal;
  • contamination of the nozzles;
  • leakage of the float valve;
  • the seal of the booster pump is worn out.

Why the STIHL chain saw cuts out when throttle is depressed?

The STIHL chain saw has a shortage of fuel, which means that when you step on the gas the fuel goes out, and the new fuel has not yet had time to come in, which causes the STIHL chain saw to shut down.

Quite often the chainsaw engine independently picks up speed when the settings of the fuel supply in the standard carburetor are disturbed. In this case, you will need to remove the unit, disassemble it and wash it with clean gasoline. After it dries, you need to install the carburetor back and make its settings.

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