STIHL STIHL 180 chain saw, idle speed adjustment

Repairing and adjusting the carburetor of a STIHL 180 chainsaw

The STIHL MS-180 has only one carburetor adjustment screw. the no-load adjustment screw. And the full-load nozzle is stationary, i.e.е. unregulated, and the full-load setting cannot be changed (the carburetor is factory set so that the engine is supplied with an optimal fuel-air mixture under all operating conditions).

It’s one of the best STIHL chainsaws to start with, but it has some inherent weaknesses. Here’s our STIHL chainsaw repair manual:

Chain oil leakage.

This is a problem that you will sooner or later face. This problem is caused by leaks over time at the hose connection between the oil tank and the oil pump. The trouble with fixing it on the STIHL STIHL 180 chain saw is that it is almost completely dismantled.

The STIHL MS-180 chain saw just won’t start.


What do you do then, you may ask, and we will tell you:

The first thing to do is to open and then close the fuel filler cap. Check the combustion chamber

A STIHL STIHL 180 chain saw normally starts after these three steps. Then if the STIHL STIHL 180 STIHL does not start, check the air filter, check the fuel system, check the spark plug and examine the condition of the spark plug.

The problem is caused by a clogged drain valve (the valve that equalizes the pressure in the gasoline tank when fuel is depleted). When it gets clogged, it creates a vacuum in the gas tank, making a big impact on the fuel supply. If the breather in your chainsaw is clogged, it can be cleaned gently with a needle.

Customers often come to us with this chainsaw, and we’ve listed two major problems with this chainsaw. It’s also very common to have a STIHL 250 chain saw repaired.

At the service center for repair of gasoline tools “Merry Lumberjack” repair of STIHL chain saw 180 fast and qualitative!

Carburetor adjustment

If your STIHL 230 chain saw starts and shuts down or just unstable, then it’s time to look at what’s wrong with the fuel system, namely the carburetor. It is most likely the cause, and it needs to be serviced. We will not dwell on this process in detail within the framework of this article, because.к. Previously told about carburetor repair on STIHL chain saws in general and STIHL in particular. We recommend to read articles: the device and adjustment of the carburetor on chain saw STIHL 180 and the second interesting article about adjustment of the carburetor on chain saws in general.

In these articles, we discuss the causes of the buzz saw’s malfunctions. Detailed and detailed answers are given, which will help to make repairs on your own hands.

If you don’t have access to a STIHL servicing dealer for whatever reason, and would like to adjust the carburettor on your chain saw yourself, then you should certainly watch these informative videos on the subject. We present to your attention, our selection.

There is no difference between the carburettor adjustment on STIHL 230 and 250 saws, and watching the video is useful for both owners of these machines.

Let’s take a closer look at each element

Fuel Pump

The fuel pump is the device that pumps the gasoline from the tank to the carburetor. It is located directly in the carburetor housing. The fuel only comes in small portions. The diaphragm is responsible for exact volume of supplied air. At the required moment, by the air pulses from the chainsaw crankcase, it opens and lets the air flow through. To prevent air infiltration from the outside, a special gasket is located between the diaphragm and the housing to ensure a tight connection.

Distribution Chamber

The distribution chamber is responsible for the gasoline supply. It has a special diaphragm. The diaphragm, as well as the diaphragm, is responsible for the accurate dosing of the petrol. The diaphragm opens at the right moment and presses on the rocker arm, which is connected to a needle valve. Between the chamber cap and the carburetor body, a gasket is installed, which is responsible for the tightness of the connection. The cover itself is fastened to the housing with 4 screws.


Nozzle, and it is often called nipples, is designed for mixing fuel and incoming air, thus forming a fuel-air mixture, which is fed into the combustion chamber under pressure. It is built into the carburettor body and has a check valve that prevents back air pressure. The air is pressurized simultaneously with the gasoline at the nozzle, mixed and sprayed in precisely metered portions.

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Throttle valve

The throttle valve is a mechanical valve that controls the volume of the fuel mixture that enters the combustion chamber. The throttle valve consists of a valve, spring, and adjusting screw. It is mounted directly in the carburettor housing on a shaft that runs through the entire carburettor housing. A throttle cable is attached to the shaft and connected to the throttle valve.

When the throttle is pressed, the valve opens, increasing the passage section, thereby increasing the capacity of the channel and the volume of fuel fed into the combustion chamber. The choke opening angle depends on the throttle pressure. The harder it is pressed, the greater the angle at which it opens. The power transmitted to the chain saw chain depends on the amount of fuel mixture burned. With the adjusting bolt, we can control the degree to which the choke is open by increasing or decreasing idle speed, by opening it slightly, or by closing it.

The choke

The air damper is used to start the engine for the first time when it is still cold. The air damper, which we have talked about many times on is structurally located on the back side of the throttle, and the engine control lever is responsible for its opening and closing. During cold start, the choke must be open for maximum airflow. It closes automatically after the engine has warmed up.

How to adjust the carburetor on a STIHL 180 chain saw

All of the following applies to any chainsaw, including chain saws, scythes and other machines. Making allowance, of course, for the design features.

There is an opinion that it is better not to get into chainsaw on your own. For those who are used to working with a hammer and sledgehammer this may be true. As for the rest, any problem with its work can be fixed by any neat person, who does not have trembling hands. All in all, it’s a job that anyone can do.

Of course it happens that the problem can not be solved independently. And you need to go to the service center.

But first of all, 90 percent of failures are usually solved by simple flushing of jets or, in the worst case, replacement of membranes or adjustment of the needle, and secondly, in the worst case, even if you’re desperate, the carburetor, which was removed from the saw can be easily replaced.

Of course, a new, original one costs a bit too much it is possible to buy it in a store known to all or from russian dealers. In general, there is nothing to lose. let’s get into the carburetor!

Malfunctions, which can be eliminated by carburetor repair

Starting off, diagnosis is a tricky thing. Sometimes the same symptom is caused by completely different things. But we’ll check and find it together. So:

stihl, chain, idle, speed, adjustment

The chainsaw does not keep idle speed. Either it stalls at idle, or they stray, or high

The idle speed nozzle may be clogged. It needs to be cleaned. How to do it. here is how. But for now about the alternative causes.

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

Sometimes the problem with idle speed can be solved by clearing the check valve in the fuel tank (the gasoline is trying to escape from the tank, but instead of getting air). It looks like the one shown in the picture below:

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

stihl, chain, idle, speed, adjustment

Saw won’t start

A particular case of the previous problem. Same solution is needed.

Saw loses power, increases fuel consumption

Two very subjective indicators. Instrumental measurements are needed to make a reliable statement about one or the other. From the practice of repair organizations, often quite subjective things are given off as one or the other.

In some cases, a loss of power can be mistaken for a dull chain. Performance is likely to be poor in this case. Sometimes the saw seems to run quieter (clogged cooling system, exhaust system).

High fuel consumption can be caused by fuel leaks.

Often the problem is in the muffler, not the carburetor!

The chain saw stops when hot: after working and warming up

  • Problems with the carburetor (on how to fix and diagnose. below);
  • Overheating. cooling problems. Clean your saw;
  • Lack of air supply;

The chainsaw starts to stall or change rpm when tilted on its side. In the vertical. everything is fine, when you turn. rpm drops (or rises) and she stalls

It is connected with features of a design of its fuel system, filling of chambers. In addition, be sure to check the gasoline pump. sometimes the problem may be in it.

Preparatory work

First of all, it is necessary to understand that the carburetor of any engine is a node, in which the flows of air and gasoline converge. Therefore, for its normal operation, these streams must come in a serviceable, unclogged form. In addition, the combustion products in the engine must freely leave the chamber through the muffler. Therefore, each time, before repairing and adjusting the carburetor in the mandatory manner check:

  • Air filter at inlet;
  • Remove and clean muffler;
  • We check the absence of problems with the fuel system. supply hoses, the serviceability of the gas tank (the work of the breather compensating the reduced pressure, see above);
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Basically, it’s not even that vital to rev the idle speed. Serviceable elements will already give normal operating characteristics.

Removing the carburetor

The removal process is best illustrated in the video below. There you can see the basic minimum steps to make the assembly operational. Schematically, the process looks like this: remove the cover, tie rods, unscrew the unit.

Replace and Check the Diaphragms

A large part of the problems with the assembly are caused by worn or malfunctioning carburetor diaphragms. The easiest thing to do is replace them if they haven’t been done in a while. In repair stores or on Aliexpress they sell complete kits that contain all necessary diaphragms. Sometimes for about 600 you can buy yourself parts for the life of the chainsaw (see. Figure.).

And in this particular case the set includes also the rocker and needle, which are also subject to wear and in some cases require replacement. In short, for the price of a new unit, you can repair the old one almost indefinitely. If you consider that five is actually a lifetime set.

stihl, chain, idle, speed, adjustment

Checking spark plugs and ignition system

According to the manufacturer’s recommendations, the spark plug should be replaced annually, regardless of the intensity of operation of the tool. Failure to follow these tips leads to a quite natural result: malfunctions at idle speed, subsequent failure of.

Typical defects in the ignition system are as follows:

  • The spark plug is flooded with fuel at startup. Remove the spark plug from its seat, dry it and if possible, blow it out with compressed air. Drain any remaining fuel from the cylinder through the setting hole and blow it out with compressed air. Then install the spark plug, connect the high-voltage wire, start the engine.
  • No spark on the spark plug electrodes. Disconnect high-voltage wire and check if the spark is there. If the spark is normal, check the connection, fix the defects found. Lack of spark on the high-voltage wire indicates a malfunction of the ignition unit. This unit is beyond repair and must be replaced with a new one.
  • The clearance between the electrodes of the spark plug is broken. This parameter can be in the range of 0,2 to 0,5 mm for different types of units. Check and correct with a special dipstick or caliper. Consult the tool’s instruction manual for the required value.
  • By the appearance of the spark plug you can determine the direction of the search. If the spark plug is dry after several attempts to start the engine, it means that there is no petrol in the cylinder. The fuel system and carburettor should be checked.
  • Black soot or carbon deposits on the electrodes indicate improper carburetor adjustment or clogged air filter. Possibly bad fuel with high oil content. When the ignition system is operating normally, the electrodes have a uniform gray color and brown deposits on the insulators.

Mesh filter in the carburetor

The last possible place for a blockage to form is the strainer in the carburetor. The diagram below shows the number 13.

To clean the strainer, you must remove the carburetor from the Windshield 180 chainsaw. Work begins by removing the top cover of the saw and then unscrewing the two nuts with an 8mm socket. It is also removed from the filter housing guides, and then the choke rod and engine control lever are disconnected. Finally, the fuel hose and the choke are disconnected, after which the carburetor can be removed from its guides.

The carburetor filter is installed in the fuel pump chamber, to reach it, one screw fixing the pump cover is loosened and removed along with the gaskets.

Clean the strainer, you can only use compressed air. Any mechanical methods are strictly prohibited, as the reticle is very soft and easy to change shape. When you squeeze it, it easily crumples, and there are bends on the edge of the seat that prevent filtered fuel from entering the carburetor.

During cleaning, the seat with the filter installed in it must be half-closed with your finger and then only blow air, otherwise the mesh may fly away and you will no longer be able to find it.

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

Adjusting the carburetor on a STIHL 180 chain saw with your own hands is easy enough. The most important thing is to do the job carefully and responsibly. To make it easier for you to understand what follows, we have prepared a detailed instruction.

Adjusting the carburetor on the STIHL 180 chain saw.

The first step in carburetor adjustment on a STIHL 180 chain saw is to check the maximum RPM. At the highest level, there is bound to be an ignition misfire. to correct the problem, make a small counterclockwise turn of the screw. Once the ignition operation is normalized, this adjustment step is complete.

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Second stage. Checking STIHL chain saw acceleration. To do this, smoothly press the gas pedal button and observe how quickly the engine accelerates to maximum rpm. If the process is too slow, turn the L screw counterclockwise. Step. 1/8 turn. Repeat until the optimum position is found.

Check and adjust the carburettor at idle. start the engine and check for regularity when the chain is at a standstill. Correct adjustment is proof that the engine runs smoothly.

Test the engine at different loads and operating conditions. If the STIHL STIHL 180 chain saw is running smoothly. You can adjust the carburetor on a STIHL STIHL 180 chain saw with your own hands.

The STIHL 180 chain saw carburetor adjustment, for which you can watch the video guide on our website, is within the power of every tool owner. But if you are facing more serious problems which you can’t solve by yourself. Become a client of the RemTechService service center. our masters will promptly eliminate breakdowns of any complexity. Also, our company sells spare parts for STIHL chain saws. both original and more affordable analogues.

Adjusting the carburetor after the Moto-Saw has run-in

After the run-in on the saws only fine-tuning of the UPT is done. This requires a tachometer and the technical documentation for the cutting tool used. The fact that the manufacturer has already set almost optimal settings. Just to run-in engine and lapping other moving parts of the chainsaw, the carburetor is set to make a slightly more enriched than the calculated optimum, fuel-air mixture. Due to it the maximal frequency of revolutions is a little bit lower constructively put by the manufacturer and plus to it the engine is better lubricated. Thanks to this, the running-in of the engine and the other moving parts is done in a gentle way.

Therefore, if there is no tachometer and/or reliable information (passport data) about the maximum RPM and idling, it is not worth to change the factory settings after the running-in period, because it will not be possible to do it correctly. In general, the fine adjustment in this case is not necessary. the chainsaw will perfectly work and on the existing basic settings. If you have to do it, you’d better do it in a service center. The fine-tuning of the carburetor of a still-new tool is recommended to be entrusted to specialists.

It is strongly recommended that you mark the previous position of the adjusting bolts as accurately as possible before carrying out the fine tuning work yourself. This allows you to return them back to the basic factory settings in case of an unsuccessful attempt. Start with bolt “H” for adjustment. After setting the maximum rpm, check the idle speed. If they differ from normal, adjust them first with “L” and then with “S” (“LA”, “T”). In doing so, we are guided by the rules and principles outlined in the second chapter of this article. But turn the adjusting bolts, focusing on the readings of the tachometer. Then continue to adjust the carburettor as described in the same chapter. Turn the screws while watching the tachometer.

Checking the correct setting of the STIHL carburettor

The implementation of the check on the correctness of the carburetor is carried out in two stages, where 1. is carried out during the setting of this unit, 2. in the course of the work tasks of the power tool. And so, is performed:

  • Checking the maximum rpm when adjusting the carburetor on your STIHL chain saw. At the highest rpm, there will be an ignition misfire, which can be adjusted by turning the screw slightly counterclockwise. As soon as the ignition is aligned, the check is complete.
  • Checking chainsaw acceleration while adjusting the carburetor assembly of the Chinese saw. Performed by smoothly pulling the throttle trigger, at which the engine should perform a steady acceleration to the maximum revolutions. Slow RPM requires the L control to be turned back against the clock, starting at 1/8 of a turn.
  • Check the accuracy of adjustment of the carburetor chainsaw ms 660 or other chinese you have at idle for engine stability, lack of movement of the chain.
  • Performing minimal manipulation of the wood in operation.

These same actions are also acceptable when servicing a hedge trimmer with malfunctions. But if you have more global problems, you will be helped by the masters of “grass cutter Motors”, which will perform all the actions as quickly as possible. Also, for repair situations, the online store offers the necessary spare parts, as a Chinese chain for a chainsaw or elements of the piston group, ignition, and much more.

Cutting and grinding wheels have a wide range of uses, and grinding wheels are effective and easy to use

Blades differ in how many teeth and what material they are made of. STIHL 180 chain saw carburettor, no-load adjustment. Adjustment. But the most important question is the grass we are going to work on.

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