How to adjust the carburetor on a STIHL 250 chain saw

Adjusting the carburetor STIHL 180 with his hands video

The first thing to determine why it may be useful to adjust and repair the carburetor STIHL ms 180. What is needed, it should be done in the following cases:

  • If the chainsaw does not hold idle speed;
  • Repair will be required if the saw does not start;
  • Loss of power is observed;
  • Excessive fuel consumption;
  • Your chain saw is not running at maximum speed.
  • throttles at revolutions.

The myth list is an option to continue for a long time, alas the main prerequisites we have conditioned. Before we start with the adjustment, it’s worth knowing what the carburetor on the STIHL 180 chain saw consists of and who makes it.

How to keep your chainsaw running

The most important thing with any chainsaw is to change the filter elements before and after use. No need to change every year or six months, change your bowl more often. Better safe than sorry and spend 100, rather than ruin your tool and pay thousands.

Second, watch the tension of the chain and be sure to loosen it after work, especially in the winter.

Third, work only with a sharp chain. If the chain is blunt, the sawdust becomes like dust, quickly clogs the air filter, penetrates where they do not need to be, as a result the ventilation system suffers, the engine overheats. Also due to the lack of necessary resistance, the engine may develop increased speed, which is also not good.

STIHL 250 chain saw: carburetor adjustment

The first thing you should do is pre-service the chainsaw, the process includes:

  • Cleaning the air filter;
  • Cleaning the carburetor;
  • Flushing the engine of dirt and dust;
  • Chain adjustment;
  • replacement or cleaning of the spark plug;
  • adjusting the idle speed.

Warm the engine up well so the engine is stable and the carburetor has the necessary speed. The STIHL STIHL 250 chain saw is then adjusted in the following steps:

  • Find the screws ” H ” and ” L ” with the chainsaw plugged in. Turn them all the way in and turn them out one turn.
  • Start the machine and let it run idle for 5-10 minutes.
  • Reach maximum rpm (14,000 rpm).). Squeeze the throttle and adjust the screw ” H “.
  • Find the “LA” bolt and use it to adjust the idle speed until the chain turns slightly. Then loosen the screw by ¼ turn.
  • If the STIHL 250 stops or the engine speed is unstable you need to loosen the ” L ” screw. During this time, the engine RPM should increase.
  • The last step is to reach optimum idle speed. the chainsaw should be running at about 2,600 rpm.
  • STIHL 250 chain saw carburetor tuned!

Note that this procedure might not help if there is an air leak in the engine. It is often found in the gasket between the carburetor, the crankshaft oil seals or the booster pump. Pay attention to the working environment, depending on the temperature conditions the saw may operate differently.

If it is checked in good time the result is long service life, less oil and less fuel consumption for your STIHL chain saw.

If the tool fails to operate, the first thing to do is to locate the cause of the fault. A tool for the repair of chain saw is suitable most common: a variety of screwdrivers, socket and wrenches, hexahedrons.

the screws for the highest and lowest revolutions should be turned clockwise until the highest resistance is reached. When the screws have reached the stop you need to turn them in the opposite direction and leave them after 1.5 revolutions.

The engine is turned on at medium rpm and heated up for about 10 minutes. The idle speed adjusting screw should be turned clockwise. Release it only when the engine reaches the stable operating mode. Make sure the chain does not move during this process.

Preparing to Adjust the Carburetor

The STIHL 250’s top fuel adjustment screw, near the muffler, is the primary setting for tuning all fuel dosing characteristics. The factory setting, the parameters of which are shown on the top plastic cover, stipulates that it must be unscrewed one turn from full twist.

During the process of operation, the carburetor adjustment of STIHL STIHL 250 chain saw with their own hands. Turning the screw out enriches the working mixture, because the air-fuel mixture gets more gasoline, and turning the screw in impoverishes the working mixture, because the air-fuel mixture gets less gasoline.

Adjusting the carburetor will not work if there is air leakage from the engine side through the carburetor:

Only after a thorough inspection of your STIHL 250 carburetor should you adjust it and check for leaks. The next stage of the preparatory adjustment work is a complete maintenance of all nodes and mechanisms.

  • cleaning of deposits, slags, resins;
  • washing the engine using solvent, acetone;
  • change of spark plug;
  • air filter cleaning, washing;
  • Checking tension of cutting chain;
  • adjustment of the idle speed;
  • warming up the engine up to operating temperature.

Then you can proceed to the complex manipulation of the adjustment.

How to properly adjust the factory saw

Adjustment of the carburetor is divided into two main steps. The first is called the basic. It is made with the engine on. The second is performed when the engine is warm.

In order to carry out the procedure of carburetor adjustment successfully, it is necessary to read the instruction manual of a particular model in advance to identify additional features of the adjustment of the device.

Initial stage

The high and low adjustment screws should be turned clockwise until the highest resistance is felt. When the screws have reached the stop, it is necessary to turn them in the opposite direction and leave them after 1.5 revolutions.

Main stage

The engine is switched to medium speed and heated up for about 10 minutes. The screw for adjusting the idle speed must move clockwise. It should only be released when the engine is in the stable operating mode. Make sure that the chain does not shift during this process.

When idling, the engine could stall (see the reason here). in this case, immediately turn the adjusting screw clockwise as far as it will go. Occasionally the chain starts to move. In this case, turn the adjusting screw in the opposite direction.

Read also: Grinding-brush drums for machine tools

Checking the acceleration function

It is necessary to do a little research. The acceleration of the device is initiated. You should assess the engine’s performance during the maximum revolutions. When the engine is functioning properly, it means that when you press the gas pedal, the speed rises quickly to 15,000 rpm.

If this does not happen or the increase in speed is too slow, you must apply the screw marked L. It is turned counterclockwise. It is necessary to observe moderate movements, because the turn cannot be more than 1/8 of a full circle.

How to adjust the maximum rpm

To limit this you need to use a screw marked H. To increase the number of revolutions, turn it clockwise, and to decrease it in the opposite direction. The maximum frequency should not exceed the value of 15000 rpm.

If you turn it more than this, the engine of the device will be worn out and this will cause problems in the ignition system. When turning this screw it is necessary to take into account the ignition processes of the device. If there is the slightest problem then the maximum rpm should be reduced.

A final check at idle speed

Before this procedure it is necessary to perform a full adjustment of the carburetor components at maximum rpm. Then perform a check on the function of the unit when idling. When the correct parameters are achieved during adjustment, it is possible to notice the exact compliance of the carburetor design with such criteria:

If you notice abnormalities in the above mentioned parameters or if the adjustment of the unit has not been carried out completely, the main stage of adjustment should be repeated. Sometimes the steps are not performed properly. In this case, the device may fail due to the loss of the correct settings of the unit. In this case it will be necessary to contact a specialist.

Disassembly of the carburetor when it is necessary to check or repair component parts

The device of different models of carburetors is almost the same, so when working with them, you can use the standard scheme. All elements must be removed carefully, and then laid out in the following order, so that you can successfully arrange the items in place at the end of the repair work.

  • The top cover is removed. Unscrew the 3 bolts that hold it in place all the way around.
  • The foam is also removed, as it is the top component of the air-conducting filter.
  • The fuel hose is removed.
  • The drive line is located directly on it.
  • Disconnect the cable lug.
  • The gasoline hose can be removed completely by pulling it smoothly off the connector.

To finally prepare the carburetor for an overhaul or replacement of the smallest parts, it must be carefully disconnected from the main system. Sometimes it requires further disassembly. Unscrew the parts carefully and stack the fasteners in groups, because it is easy to lose these small parts.

How to adjust the saw correctly made in China. the adjusting instruction

To properly perform the adjustment of the carburetor of a Chinese chainsaw, you must first remember the factory settings of the device, then turn on the engine. Afterwards you will have to leave it running for a few hours to fine tune your own settings. Sometimes the work is carried out once the engine has been running for ten minutes, but many Chinese models require special handling.

  • Activities begin in the idle mode. With the help of adjustment screws you need to achieve a smooth engine speed gain, so you should first let him work at low revolutions. The chain is moved along the bar. In this case, it is necessary to adjust the optimum position with the end screws so that the chain stays stationary.
  • Moving to medium speed revolutions. Sometimes the engine starts to smoke when you do this. This defect can be eliminated by screwing in the screw for a leaner fuel mixture.

In this case, the smoke will disappear, but the engine speed will increase. Adjust throttle settings until you reach a level where the engine picks up quickly, without jerking or jerking erratically.

Before buying, with a chainsaw rating for reliability and quality. See visually at

Revision or preparatory work with a chainsaw

How to check, preventive and preparatory maintenance of a chainsaw is demonstrated in this video. Every tool needs attention. To keep it running reliably and without malfunctions, it’s important to do the work in good time.

We need to do a little research. The acceleration of the device is initiated. Check engine condition during maximum revolutions. When the engine is functioning properly, it means that when you press the gas pedal speed quickly increases to 15000 rpm.

If it does not, or if the increase in speed is too slow, it is necessary to apply the screw marked L. STIHL chain saw carburetor repair STIHL Grass trimmer repair with your own. It turns counterclockwise. Moderate movements must be observed, since the turn cannot be more than 1/8 of a full circle.

Additionally: chain for chainsaw longitudinal

Operating and maintenance instructions

STIHL 250-ms model operating instructions:

  • After assembly, the tool needs a running-in period before starting regular operation, the running-in period takes about 5-7 hours, during which time the intensity of the chainsaw should be medium;
  • After the running-in period, you may switch to normal chain saw mode, avoiding overheating the engine and bar;
  • It is recommended to use the saw only in protective gear;
  • Do not drop the tool when it is in operation.

Maintenance:

  • complex repairs or repair of serious malfunctions, while the chainsaw is under warranty, must be performed by a service center;
  • Do not disassemble the STIHL 180 as long as the warranty is valid;
  • Self-adjustment of the carburetor is carried out after the end of the warranty, in the previous period. by the service specialists;
  • the diagram of the general adjustment of the machine before use is described in detail in the instruction manual;
  • regular inspection for integrity, cleaning the air filter from sawdust, lubricating the tire and chain, once a month check the condition of the spark plug, the ignition system, and prepare a fresh fuel mixture, once a year the carburetor is adjusted.

Preparing to adjust the carburetor

When adjusting all fuel settings on the STIHL 250 the adjusting screw on the topmost setting block near the muffler is of primary importance. The factory setting, shown on the plastic top cover, specifies that it should be turned one turn from full twist.

During the operation the carburetor of STIHL STIHL 250 chain saw by its own hands is adjusted. Turning the screw enriches the working mixture, because the air-fuel mixture receives more gasoline, and tightening the screw impoverishes the working mixture, because the air-fuel mixture receives less gasoline.

Adjusting the carburetor will not produce positive results if there is air infiltration from the engine side through:

STIHL 250 carburetors should only be adjusted after a thorough and thorough check to see if there is any air leaks. The next step in the preparatory tuning procedure is to carry out a complete overhaul of all the components.

  • cleaning from deposits, slags, resins;
  • washing the engine with solvent, acetone;
  • Replacement of spark plugs;
  • air filter cleaning and washing;
  • checking the tension of the cutting chain;
  • adjustment of the idle speed;
  • warming up the engine to working temperature.

Then you can proceed to the complex manipulation of the tuning.

Grass trimmers and chain saws

The necessity of the operation “Adjustment of the chainsaw carburetor” is determined by the color of the spark plug electrodes: if black. it means over-enrichment, if brick-gray. it is normal, if a white deposit on the spark plug electrodes. it means the mixture is depleted. The carburetor adjustment on STIHL chain saws is mainly performed by the upper screw (the one closest to the muffler). According to factory parameters (it is specified on a gasoline saw cover) it should be twisted off on 1 turn, and further it is necessary to correct. if to twist it off, the working mix enriches (more gasoline gets into the air-fuel mix), if to twist in this screw, then the working mix becomes impoverished (less gasoline gets into the air-fuel mix).

Repairing the carburetor on the STIHL MS 250 chain saw

I replaced the gas pedal pump o-ring, I’ll see how it is.I already changed the kit (piston and o-ring) was purchased at a brand-name Schwill shop.The oil has had a season and the ring is worn out.

Hello Artem, I have a problem with the 250, I did everything as you told me, removed the grid, removed the gas pedal, put a weight on the carburetor, the studs on the carburetor are in place. Everything’s the same, no idle, no power when I run it. Did not change carburetor settings before and after. Tell me what to do?

advise 250 STIHL flooded the cylinder pump stalled the pump began to flood the entire thing now does not start what to do?

Hello Artem. 2 tips. STIHL 250. The spark is there but the spark plug is totally dry. The saw won’t start at all. Haven’t used it for over two years. Maybe it’s the booster pump?

HELLO.MY SPRING 2021.I’VE GOT A 250 STIHL, I’VE GOT A STIHL GAS PEDAL, I’VE GOT A STUBBED OUT GAS PEDAL IN THE HOLE.PICKED UP A RUBBER RING WITH MTZ.82 WHICH ARE INSTALLED IN THE SLEEVE, CUT TO THE LENGTH OF THE PISTON, JUST FIT TIGHTLY THERE AND THE SAW BEGAN TO WORK FINE.

half a minute cold and hot starts

Hi Arthur.advise STIHL ms 290 saw starts tripping and shakes when warmed up.RPMs float badly.what can be?

my saw sucks air in the tank how so what is the cause tell me

Artem may be able to advise. I have this problem with my ms 250. After 15-20 minutes the saw loses power and shuts down. I remove the low cap from the carburetor and there is a cavity with a sieve, on this sieve can be a little dirt. I clean, reassemble and all is well, but only for 20 minutes or one tank. All diaphragms changed, fuel filter 2 times. Maybe you know how to fix the problem?

I had a problem with the carburetor 361? repair the same?

The method helped, thank you! I had a 250 that started great but stopped right after I hit the gas. It was trying to keep the throttle on somehow, if I pressed the gas very slowly, gradually, but in the end. it was still puffing Removed the carburetor, disassembled, removed the booster pump and hammered into the hole from it, but not a weight, and a piece of rubber (I inserted a rubber, not hammered weights, I to, that you could. if the problem was not in this. to play it all back. take out the rubber band and insert the booster pump back and check the other causes. air leaking in the crankshaft seals, for example) But immediately everything worked. and starts well, and accelerates, and resets (but without load. I do not yet have at hand tire and chain). I was turning all the screws on the carb before that. How do you adjust it back to the factory settings? I still have adjusted so:. screw L (top right). screwed all the way clockwise and unscrewed counterclockwise 1 turn;. screw H (top left). screwed all the way clockwise and unscrewed half a turn counterclockwise (and the maximum it can unscrew 3/4 turn, but whether to?). the L/A screw (bottom). turned it all the way clockwise. the saw screamed when idling. I started unscrewing it counterclockwise until it stopped screaming and just started ramming. If you keep unscrewing it further, the saw shuts down. I found about this position, when the saw doesn’t idle and doesn’t scream too much, but just rattles When I can put the tire-chain. I’ll make a better adjustment. until the chain starts moving on its own. So far at these settings all works fine and gazovatsya (without the bus)). Is this a good setting or should the factory settings for the top screws be something else?

on the FS-130, the fuel pump does not work, I did not free the carburetor from gasoline for the winter?

Artyom thanks for the video. helped, ! I’ve been having this problem for a long time. I cut off the ring from the gas hose from an old 180 Stihl just right in diameter, a little work. and it worked like a charm. Then I’ll buy an accelerator kit just to be sure. Thanks again.

Thanks. You answered a question that puzzled me by 180. Same problem with the high rpm. It stops and won’t start. I went to the service department and bought a gas pedal repair kit. Thank you ! Maybe the gas pedal is in the 180 as well ?

Hello, but here in the chainsaw forestnik5220 carburetor as you can fix it there is no such a piston and stands a ball and I put the carburetor with the same brand forestnik4518 it may affect the engine Thanks in advance.

Hello a can not prompt what the factory carburetor settings that is (how many turns should be on the screws L and H from the fully turned state) Son took off the carburetor to wash completely unscrewed the screws L and H and how many turns was not remembered to know at least the initial number of turns of these screws. Thanks in advance. P.S. It does not say anything in the passport of the saw, the saw KEDR BP-45-3,0

I wouldn’t recommend using red sod. it’s not good with gasoline and when it corrodes, the red sod tends to get into the cylinder.

I successfully removed the gas pedal and put a weight in my ms 250, saw worked great right away, Thanks.

When is adjustment necessary for your STIHL 250 chain saw??

You may need to adjust the carburetor when changes in fuel quality occur. It is also important to consider operating conditions, e. g. how thin the air is and whether the pressure varies or not. Humidity and air temperature can affect the need for adjustment.

By doing this you can achieve better performance even if conditions deteriorate. Do-it-yourself adjustment of the STIHL 250 chain saw carburetor helps prevent oil starvation. By not doing this, you could be facing engine failure, which would result in insufficient lubrication. It is fed into the cylinder from a lean mixture.

How much does a new carburetor cost?

Medium The question is whether these are original carburetors. In online stores

STIHL 180 chain saws are in high demand in Russia, primarily because of their reliability. Similarly, the carburettor is reliable and user-friendly. Adjustment or repair of the carburettor is only necessary after long periods of use, at least 5 to 7 years (at average use). Tuning itself is made easy by STIHL engineers. this is the first chainsaw with only one screw for adjustment.

STIHL chain saws can be repaired by the user himself thanks to their simple design. Proven in the construction segment of the tool has a power of 1400 watts, engine capacity of 31 cc. see.

The tool has excellent recommendations, popularity among users. This is due to a reasonable price and quality characteristics. However, chainsaw use is occasionally accompanied by breakdowns.

Disassembling the STIHL 180 carburetor

To bleed, change gaskets or needle valves, the carburettor has to be disassembled. You unscrew the 4 screws on the compensator cap and one on the fuel pump.

When you open the housing, you need to be extra careful because the thickness of the channels is comparable with the thickness of the carburettor. к. If there is debris inside the carburetor it will make it impossible to operate. Thickness of the channels is about the thickness of a thread or even a human hair.

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I would like to reiterate that STIHL carburetors manufactured by its subsidiary Zama are very reliable. With proper use and storage can last the entire life of the chainsaw without repair.

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