Adjusting the carburetor on a STIHL STIHL 180 chain saw with your own hands

STIHL STIHL 180 chain saw. carburettor settings and adjustment

You can’t do without a chainsaw in the home. That’s why you need to know how to use and maintain it. First and foremost, this applies to the performance of the carburetor. This is the part that determines how well the chainsaw performs. That’s why STIHL chain saw carburetors need to be adjusted in time. With knowledge and a little experience you can do it yourself.

Troubleshooting and repair

The carburetor on a STIHL STIHL 180 chain saw requires adjustment at regular intervals or for the first time. It is possible to know about its necessity by the following signs:

HOW TO. Carburetor & Fuel Line Repair on STIHL 017, MS170, 018, M180 Chainsaw Part 1/3

  • Engine problems, such as the engine not starting or immediately shutting down after starting. The most common cause is the use of a low-quality fuel mixture.
  • Fuel consumption and increased emission. Exhaust emissions are higher due to incomplete combustion. Most of the time this problem is caused by too much fuel.

Other malfunctions may also occur, such as clogging due to a damaged air filter or scale formation. Causes may be due to gasoline remaining in the fuel tank when idling for long periods of time. This is due to the fact that the fuel is exhausted, which spoils the device.

Regardless of the cause, carburetor repair will be required, and most often involves adjustment. The way to perform this procedure depends on the model of the chainsaw, but you can follow the general principles.

adjusting, carburetor, stihl, chain

How to remove the carburetor from a chainsaw

Before adjusting, you need to remove it from the STIHL chain saw. To do this you need:

  • Turn the catch to the left to remove the cover.
  • Remove the filter by unscrewing the two nuts that hold it. For ease of operation, it is recommended to use special screwdrivers with suitable tips.
  • Remove all the rods, including the carburetor lever.
  • Remove the carburetor and then disconnect the fuel hose.

It is recommended to memorize the location of parts so that you can then put the carburetor in place and no unnecessary fasteners or warping and slots.

How to clean

If the chainsaw stalls when idling, disassemble the part and clean it. First of all it concerns the cleaning of the additional filter. This part is a gauze. To get to it, you need:

  • Remove the largest cover.
  • Remove the diaphragm, which is located under the cover.
  • Clean the filter in the recess of the carburettor. Be very careful when doing this because the gasket might fall out. Use a copper wire for cleaning. Additionally, all passages should be flushed and blown. The last procedure is necessary if the carburetor does not receive gasoline.

How to Adjust

Adjusting the STIHL 180 Series chain saw carburettor to improve performance and fuel economy.

  • Clean the fuel system and fuel tank of gasoline and oil residue. Blow out the air duct and filters.
  • The chainsaw carburetor is adjusted with the H, L and S bolts. The H bolt controls the nipple and gives the best rpm. The L bolt performs the same function, but provides minimum rpm. The S screw controls the accuracy of the idle speed. Perform this procedure with the engine off.
  • Adjust the carburetor on the chainsaw by setting the angle of rotation of the first two bolts. Set the basic values as follows. Turn the first two bolts slowly in a clockwise direction and go back two revolutions after the stop.
  • Start the engine and adjust the ignition on the STIHL chain saw and its carburetor. To do this, find the highest idle speed by turning the bolt L in different directions. Once this maximum is reached, the bolt should be returned a quarter turn. If the chain starts to move, stop the engine.
  • Carry out a technical check. In particular determine the maximum rpm, check the engine acceleration and idling stability as well as the correspondence of these parameters to the basic values in the manual. The mixture quality for the test should be the highest.

Bottom line

This model is the pride of the German manufacturer and is a specific piece of equipment created for a minor level of work. It is used for less than 20 hours each month. This beautiful device has no problem to help you care for your garden, make firewood for the cold period of time (see the “Powerful” and “Powerful” models, see the “Powerful” and “Powerful” models).

We must say that this is a mini chainsaw because it has a low weight of 3.9kg, it has a low oil tank weight as well as a low fuel tank weight. The manufacturer has equipped this device with a two-stroke engine with enough power for light work.

In addition, it is quite quiet because during operation the noise level does not exceed 98 dB. So that you better understand the volume itself, just compare its noise to the spoken word, which has a value of 76 dB.

The power of this model is equal to 2.6W. It is worth noting that this is a fairly significant level of power, given that it is not a professional chainsaw. The oil tank has a volume of only 0.145 liters and the fuel tank is 0.25 liters. The bar has a size of 350 mm and a pitch of 0.325 inches.

This model is the pride of the German manufacturer and is a straightforward tool designed for a minor level of work. It can be used for no more than twenty hours a month. This beautiful appliance will help you take care of your garden, prepare firewood for the winter season (see more details) and make your garden safer., How to cut down a tree), clear areas and will be indispensable in other areas, say, simple manipulation.

We can say that this mini chainsaw model as it has a small weight of 3.9 kg, it does not have a large tank weight of both oil and fuel. The manufacturer has equipped this unit with a two-stroke engine with enough power for easy operation.

In addition, it is quite quiet, because during operation the noise level does not exceed 98 dB. To better understand the volume level, compare its noise to spoken speech, which has a value of 76 dB.


This model has a power output of 2.6 Watts. It’s worth noting that this is a pretty significant level of power, given that this is not a professional chainsaw. The oil tank has a capacity of only 0.145 liters, and the fuel tank. 0.25 liters. The bar measures 350 mm and is 0.325 inches high.

Faults that can be corrected by carburetor repair

Immediately stipulate that diagnosis is a tricky thing. Sometimes the same symptom is due to very different causes. But we’ll check it all out and find it together. So:

The chainsaw does not hold idle speed. Either it stalls at idle, or it staggers, or it is high.

Probably clogged idle speed nozzle. It needs to be cleaned. How to do it about it below. But for now about the alternative causes.

It is possible that the problem is in the fuel system. You should check the fuel hoses, fuel supply.

Sometimes the problem with rpm (or rather their absence) is solved by cleaning the fuel tank check valve (gasoline tries to escape from the tank, but no air returns instead). It looks like the picture below:

Don’t forget to adjust the carburettor the only way to change the amount of air supply, which affects the idle speed very much. Everything is described in the instruction manual. For those who are too lazy to look in the manual, here is a screenshot:

The saw will not start

A special case of the previous problem. The solution is the same.

Saw has lost power, increased fuel consumption

Two very subjective indicators. In order to say one or the other reliably, instrumental measurements are necessary. From the practice of repair organizations often under this or that is given quite subjective things. In some cases loss of power can be mistaken for effects resulting from a dull chain. Naturally, the performance in this case will be low. Sometimes the saw seems to run quieter (clogged cooling system, exhaust system). Increased fuel consumption may be due to fuel leaks.

Often the problem is with the muffler and not the carburetor!

Chainsaw stalls on hot after work and warming up

  • Carburetor problems (how to fix and diagnose below);
  • Overheating cooling problems. Clean your saw;
  • Lack of air supply;

Chainsaw starts to choke or change rpm when tilted on its side. In upright everything is fine, when you turn it, the rpm drops (or rises) and it stalls

Associated with the peculiarities of the design of its fuel system, filling the chambers. STIHL STIHL chain saw STIHL 180 without any downtime.

How to adjust with your own hands, nuances of tuning

STIHL 180 chain saw carburetor, without disassembly, can only be adjusted for the number of revolutions at idle speed. Increase or decrease the fuel supply in different modes with special screws cannot. Manufacturer limits access to adjustments and does not install these screws. How to adjust the carburetor to the correct idle speed is described in detail in the manufacturer’s manual.

In the case of certain malfunctions, and if you have experience, you can increase or decrease the fuel supply by increasing the gap at the opening of the needle valve.

To increase the flow, the rocker needle valve in the distribution chamber to bend upward, and to reduce, downward. Thereby the stroke of the needle is adjusted and, respectively, the valve capacity.

Do not make adjustments by yourself, t. к. this must be done very precisely and, if done incorrectly, it is almost impossible to return the rocker to its original position.

Checking and Adjusting the Carburetor

Have the carburetor adjusted with special equipment at a service center. The adjustment screws have different angles of rotation for each saw (please see the instruction manual). The need to adjust the carburetor does not occur very often, especially if the saw was purchased from a trusted retailer. All of our Husqvarna saws are sent to the service center for adjustment of engine RPM before sale.

However, misalignment of the adjusting screws sometimes occurs.

Causes of chain saw carburetor misalignment:

  • Severe engine (piston) wear and tear. In that case it is more of an engine overhaul, but a carburetor adjustment might improve the functionality of the saw for a while.
  • Clogging of carburetor due to damaged air filter, use of poor quality gasoline, and scale formation.In such a situation, in addition to adjusting the carburetor, you will also need to flush it.
  • Severe vibration of the saw or damage to the carburetor cover. It happens very rarely, but there are cases.

Signs that indicate the need to adjust the carburetor of a chainsaw:

  • Engine either won’t start or starts and then shuts down. This is caused by using a bad fuel mixture.
  • Significant growth of fuel consumption and increased volume of exhaust. Increased exhaust fumes indicate that the fuel is not burning properly. This can be caused by oversaturation of fuel.

The scheme of adjustment of the carburetor of different models of chainsaws differs and is described in the instruction manual. The general principle is the same: it is necessary to change the quantity and quality of the fuel mixture, supplied to the engine cylinder.

There are three screws to help us adjust the carburetor:

  • “L”. low, for low rpm setting
  • “H”. high, for the upper rpm setting
  • “T” (“LA”, “S”). for adjusting the idle speed (models that have only one screw have exactly the “T” screw)

When adjusting the carburetor of a chainsaw, the following rules should be observed:

  • Make sure the saw chain is facing away from you
  • Place the saw on a stable, level surface so that the cutting attachment does not touch any objects.

Note: The exact angles for the adjusting screws are shown in the manual. Avoid damaging the engine by following the instructions.

The very process of adjusting the carburetor includes two points: the basic (when the engine is not running) and the final (when the engine is warm).

Algorithm of removal and installation

If you need to clean or disassemble the STIHL 180 carburetor you will first need to remove the carburetor assembly from the chain saw. This should be done according to a certain procedure:

  • Put the chainsaw blade guard on the bar.
  • Remove chainsaw top cover.
  • Remove the two nuts that hold the air cleaner and carburetor.
  • Remove the air filter body.
  • Disconnect the wire from the engine control lever.
  • Carefully remove the lever from its seat in the housing while disconnecting the choke rod.
  • Pull the carburetor on itself and disconnect the fuel supply, as well as the throttle linkage.

To facilitate disassembly, you can additionally unscrew the rear handle and disconnect the throttle link first from it, and then only from the carburetor. This may be necessary because. к. it is hard to disconnect the pull rod from the carburetor without some experience and it is easier to disassemble the handle first.

Install the part in place, should follow the reverse order of the algorithm.

When removing and installing the chainsaw engine control lever, you should be extremely careful, because. к. the seat on the body of the saw is the weak link of the saw, and very often inexperienced users break it.

Main types of breaks and troubleshooting

Before starting work on fault diagnosis and troubleshooting, it is necessary to prepare the necessary tools.

General view of the STIHL MS 180 chain saw with its main components

Since the chainsaw is a relatively simple machine, the list of accessories includes the following items

  • A set of flat and Phillips screwdrivers;
  • wrench wrenches;
  • spark plug wrench;
  • a set of socket heads with a screwdriver
  • STIHL multi-tools.

In order to eliminate the quality of the occurring breakages and restore the performance indicators it is necessary to establish as accurately as possible the malfunction that preceded the failure of the unit. Since your chain saw is equipped with an internal combustion engine, the main causes of faults are to be found in the engine unit.

Before beginning work, turn off the engine, allow it to cool and eliminate the possibility of starting the chainsaw. To protect your fingers it is recommended to wear cotton gloves.

The most common malfunctions when repairing a STIHL chainsaw 180 include:

  • engine won’t start;
  • Short periods of non-operation may cause the chain saw to shut down automatically;
  • oil is leaking near the chain lubricator;
  • the engine does not develop full power.

Frequent failures of the transmission part of the saw can include a breakage of chain links. You can repair it yourself by riveting the links or replacing it with a new one.

Despite the relative simplicity of the design and the absence of complex mechanisms, experts recommend searching for faults in a certain order. First of all we check the presence of mixture in the fuel tank, and if the level of liquid is okay, we should proceed to the examination of the starting chainsaw. If this mechanism is also in normal condition it is necessary to check the functionality of the spark plug.

After the manipulations made to diagnose the plug (to determine the presence or absence of carbon deposits, the correctness of the gap between the electrodes, the condition of the sealing ring) we shift our attention to the carburetor. Fine sawdust, dust and soil particles often cause the fuel system to clog.

If cleaning your STIHL 180 chain saw’s carburetor didn’t help bring it back to its previous performance, the cylinder piston group is probably to blame. The power unit is one of the most complex parts of the machine and can only be diagnosed after a nearly complete disassembly.

adjusting, carburetor, stihl, chain

Fuel system malfunctions

The first place to check the fuel system is to check the fuel tank level.

Key components of the STIHL chainsaw fuel system

How to adjust carburetor of chainsaw STIHL MS 180

Even if you are sure that gas is available, it helps to rule out a vacuum caused by a clogged bypass valve. It is designed to optimize the pressure in the tank at fuel consumption. An ordinary medium-sized sewing needle is used for easy cleaning of a chainsaw breather.

When inspecting the fuel system it is worth paying attention to the integrity of the pipes, the tightness of which can be compromised by mechanical damage or prolonged use of the unit. Sometimes the cause of mixture leakage and, as a consequence, incorrect operation of the engine, lies in the wear of rubber gaskets and primer (choke button). In this case, to repair STIHL 180 chain saw with your own hands you need to buy a repair kit of seals and replace them.

Starting and ignition mechanism malfunctions

Malfunctioning of ignition system and motor starter unit may be the reason of malfunctioning of this model chainsaw.

If no deviations are found when measuring the gap between the flywheel and the module, it is necessary to pay attention to the spark plug.

Most manufacturers, including those on STIHL chain saws, recommend a 0 gap.2 mm. This requires a coin, coin-wire, or flat dipstick, which can be purchased at any auto store.

Having disassembled the spark plug from the shaft, we measure the gap of a chainsaw plug between the central electrode and the side electrode. If its excessive (more than 0.7-1.5 mm) value, the spark can occur intermittently, and at a minimum (less than 0.7 mm). insufficient for optimum ignition of the fuel mixture.

If gasoline enters the combustion chamber, and mismatch in the ignition system was not detected, the likely cause of failure may be the carburetor. This assembly is designed to mix fuel with air and feed them into the cylinder. After dismantling the carburetor clean its channels and jets with universal means.

Remember that the carburetor consists of many small parts, and therefore its disassembly, disassembly and cleaning require special care.

After STIHL 180 chain saw’s ignition system has been diagnosed and repaired you can now start looking for malfunctions in the power pack, or in the saw’s cylinder piston group.

Your chain saw engine malfunctions

The saw’s cylinder parts fail during operation because of friction forces, high temperatures and loads. If your chain saw does not develop full power and idles when starting, it may be an engine component failure. To disassemble the power unit you need to unscrew the 4 bolts and remove the cylinder. The owner needs to carefully inspect its internal working surface for chips, dents and cracks.

Even the slightest damage of the cylinder “mirror” can negatively affect the compression of the chainsaw engine and its performance.

STIHL MS180 chain saw cylinder piston group

When diagnosing the internal combustion engine we also perform a visual inspection of the piston and the compression rings. Made of duralumin and cast iron respectively, they are more exposed to abrasion stress than steel cylinders. If piston rings break and are excessively worn, they need to be replaced.

If the visual inspection shows ovality of the cylinder’s working surface, it will be necessary to bore it. To do so, measure its diameter at the larger dimension, match the piston and do the subsequent machining.

Malfunctions in the chainsaw ms 180 lubrication system: causes and repair

While sawing wood the cutting part of the tool is exposed to high loads. STIHL chain saws have a lubrication system which gradually supplies oil to the bar in order to reduce friction forces and consequent chain wear. If the tines lose their cutting action quickly and there is no trace of lubricant, there may be a leakage or blockage on the spigot.

First of all, when diagnosing the chain lubrication system for the ms 180 chain saw, pay attention to the oil hoses and the places where they are fixed. Damaged tubes are beyond repair and must be replaced. You can clean the oil ducts with compressed air. For this purpose, we use a compressor or an ordinary car hand pump.

Thanks to its ease of use and repair, this model chain saw has gained wide acceptance among professionals and amateurs in the field of woodworking.

STIHL carburettor: Adjusting the STIHL-180 carburettor: Repair and tuning of a chainsaw. How the carburettor works on a STIHL-180 chain saw

A chainsaw is indispensable in the home. That’s why it pays to know how to operate and maintain it. First of all it affects the efficiency of the carburetor. This part affects the efficiency of the chainsaw. That’s why STIHL chain saw carburetors need to be adjusted in good time and the correct procedure is recommended. With some knowledge and experience, you can do it yourself.

adjusting, carburetor, stihl, chain
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