Chainsaw calm no idle

How to start the Stihl chainsaw correctly: instructions

The tool manufacturer has taken all measures and developed a manual that makes the mechanism easy to start. The user will protect himself from injury if he fulfills the proposed frequency of actions:

  • The ignition is turned on and the engine handle is in the down position. The intake of atmosphere from the air filter is blocked by the carburetor flap. To properly start the chainsaw, the throttle membrane must be open to enrich the combustible mixture.
  • The lever is set to the start throttle position. The starter jerks several times before the first spark appears. If the flash passes, the instrument is ready to run. The mechanism runs at high revs due to the closed throttle diaphragm. To transfer it to the idle speed, the gas trigger is pressed and the rhinestone is released. The number of revolutions quickly returns to normal.
  • On the Shtil MC unit of the standard configuration, additional devices are not provided to start the chainsaw in a lightweight version.

Broken crankshaft bearings

In case of bearing defects, a slight backlash is felt. To detect it, the flywheel of the Stihl MS 180 saw is swinging from one side to the other. The movement indicates that the flywheel is being moved towards the electrodes by its own magnets, as a result of which there is no spark. To remove the mechanism, dismantle the cutting element, remove the filter and clutch cover. For the crankshaft stopper, remove the manual starter cover and tighten the two bolts.

The clutch is unscrewed with a wrench clockwise. Remove the drum with an asterisk, change the old clutch and tighten it all the way. The crankshaft is locked so as not to break the starter. The mechanism is assembled in the reverse order. To tighten, the brake handle is tilted forward, the tool is turned on, then released from the brake.

chainsaw, idle

Bearings with defects are less often detected (the diameter of the holes in the cage is increased). For determination, disassemble and measure with a micrometer. Broken bearings are indicated by regular knocking. In this case, urgent repair is required, since if the integrity of the crankshaft is violated, the piston group and the cylinder will fail.

Ignition coil defective

The module or coil cannot be disassembled and its suitability is difficult to determine without testing devices. Modern ignition systems are durable, lightweight and small in size. They are characterized by near-fail-safe functionality. Problems with chainsaw malfunction due to the ignition coil can be eliminated by yourself.

Lead wires are tested for damage (including internal ones) that arise from vibration that leads to friction. If no cracks are found, then replacement of the ignition coil is required. Sometimes a weak, subtle flash when the saw heats up indicates a malfunction of the module. This is due to an increase in the temperature of the coil, which leads to an increase in the resistance of the transistor.

The peculiarity is that at the beginning of work, a spark may appear, but after prolonged use it becomes dull and disappears. Modern ignition coils in a home workshop are not repaired, therefore they are replaced with suitable elements.

Idle speed adjustment

Before commissioning, the tool is maintained. In order for the idle speed adjustment to be effective, prevention is done:

  • cleaning the carburetor;
  • flushing the engine;
  • cleaning the air filter;
  • warming up the engine.

To adjust the operation of the mechanism at idle speed, an appropriate adjusting screw is used. Its rotation depends on the required setting:

  • With standard adjustment, the screw is turned against the clock hand to the point where it will turn tightly. After that, make 2 circles in the direction of the arrow.
  • If the saw is running at low speed, the screw is turned clockwise until the chain starts moving. Then make half a circle in the opposite direction.
  • At high frequency, the regulator is turned against the clock hand until the circuit stops. After that, the rotation is continued for another half turn in the same direction.
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It will not be possible to adjust the idle operation if there is air suction into the engine through a gasket, acceleration pump, oil seals, or for another reason.

Doesn’t slow down

The tool quickly reaches its maximum number of revolutions and the power does not decrease. This situation is explained by the fact that:

  • the throttle valve does not work due to a weakening of the spring or traction element;
  • the turning on toggle switch periodically fails;
  • no corkscrew on the throttle shaft;
  • clogged carburetor;
  • the fuel hose and the petrol filter are malfunctioning.

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Ignition setting

Gasoline engines are equipped with an ignition system that ignites the fuel. The timing of the flash will affect the performance of the motor. In mass production at the factory, the ignition of the chainsaw is not adjusted. Marks are placed on the corresponding rotating elements, which are aligned during adjustment. Incorrect adjustment leads to the fact that the mechanism starts and stalls.

Before adjusting, check the dryness of the spark plug and the performance of the ignition circuit. The voltage supply cable to the candle is brought to the cylinder with a small gap and the starter is started. If there is no flash, test the cable with a probe. Then check the serviceability of the wire to the disconnecting button.

If the cables are intact, then check the ignition coil. This is done with a special tester to ring the device. In this case, the indicators on the device must coincide with the technical characteristics of the coil, which are prescribed in the instructions for use. If inconsistencies are found, then the ignition unit changes to a workable device.

The video shows how to quickly set the gap between the ignition coil and the magnet using a piece of plastic cut from a bottle as a probe. You can also use a four-fold A4 sheet or a piece of cardboard from a cigarette pack.

The coil can be damaged by vibration if dropped or bumped, so work with caution.

At full speed

Sometimes the engine will stall after normal operation. To establish the cause, pay attention to the accompanying circumstances:

  • Motor stalls in the middle of operation for no apparent reason. The starter is stationary and does not turn. It means that the tool is jammed and requires urgent repair.
  • During normal operation, the power is reduced in a short time and the engine stops, the cylinders are overheated. The situation indicates the occurrence of air suction under the rubber pipe between the carburetor cylinder, possibly due to a rupture. Air depletes fuel, nozzle replacement required.

No spark

Spark plug test is performed. The functioning of an element is influenced by various factors. When testing the mechanism, the reasons are revealed:

  • insufficient adjustment of the carburetor;
  • large oil in gasoline;
  • clogged fuel and air filters.

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Due to work in such conditions, carbon deposits accumulate on the plug contacts. Subsequent corrosion of the conductors causes no spark in half of the fault cases. This is because the gap between the modular contacts changes. To test the spark, do the following:

  • the tip of the high-voltage cable is removed;
  • unscrew the candle;
  • the tip is put in place;
  • the candle is leaned against the cylinder with its wide end;
  • start the starter.

If a bright spark resembling lightning appears between the electrodes during start-up, then the ignition unit is working properly. In the absence of a flash, clean the entire element and expose a gap between the conductors. Sometimes there is no clearance between the flywheel and the ignition coil. When rubbing the flywheel, scratches are visible on its exterior.

Troubleshooting steps if your Husqvarna chainsaw stops idling

Adjusting the carburetor on your own on a chainsaw

Chainsaw carburetor adjustment ensures efficient operation of the tool at a workable power version with economical fuel consumption. Adjustments must be made with clean fuel and air filters. For a larger number of carburetors, adjustment is carried out with 3 screws: for high and low speed and idle speed adjustment.

Screws H and L adjust the ratio of the consistency of gasoline and air, determined by opening the throttle valve of the carburetor. When the screws are unscrewed, the consistency is enriched, and the revolutions accordingly fall, when the screws are tightened, the mixture becomes leaner. the revolutions grow.

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The designation H refers to the high speed screw that controls the main jet, L. the low speed screw controls the idle jet. The S screw is used to fine-tune the idle speed. When, to simplify options, the number of available carburetor adjusting screws is reduced.

Chainsaw carburetor setting is divided into two steps. basic (factory options), carried out with the engine turned off. and the final one, produced on a running warm engine. A clear value for the angles of rotation should be taken from the operating instructions for the particular chainsaw. Failure to follow the manufacturer’s annotations will result in damage to the motor.

Basic carburetor adjustment.

The adjusting screws for the highest H and low L turns are slowly turned clockwise in full, then unscrewed 2 turns, other options are also possible

Carburetor. How chain saws work

The carburetor on a chainsaw is pretty straightforward when it comes to carbs, but it’s not exactly straightforward. The carburetor’s job is to accurately meter out very tiny amounts of fuel and mix it with the air entering the engine to keep the engine running properly.

If there is not enough air-mixed fuel, the engine will run on a lean mixture and will either not run or potentially be damaged (in a two-stroke engine, fuel also provides lubrication to the engine). If too much fuel is mixed with the air, the engine “runs rich” and either won’t run (it floods), runs with a lot of smoke, runs poorly (withers, stalls easily), or at least waste fuel. The carburetor is responsible for preparing the mixture.

A chainsaw carburetor is simpler than most carburettors because it actually only has three situations that it has to cover:

  • It should work when you try to start a cold engine.
  • Should idle.
  • It should run with the engine fully open.

No one who works with a chainsaw is interested in any gradation between idle and full throttle, so increasing performance between these two extremes is not very important. Many gradations are important in a car, so a car carburetor is much more complicated.

The chain saw carburetor can be seen in the following two photos:

This short video (5.1 MB) gives you a quick overview of the carburetor.

Here are the carburetor details:

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  • The carburetor is a tube.
  • The tube has an adjustable plate called a choke valve. which regulates how much air can pass through the tube. You can see this round brass plate in photo 1 above.
  • At some point in the tube there is a constriction called the Venturi tube. and a vacuum is created in this constriction. Photo 2 shows the Venturi tube.
  • This constriction has a hole called a nozzle. which allows the vacuum to suck in fuel. You can see the jet on the left side of the venturi in photo 2.

Watch the video to get a better look at these parts.

The carburetor is operating “normally” at wide open throttle. In this case, the throttle valve is parallel to the length of the tube, allowing maximum air flow through the carburetor. The air flow creates a good vacuum in the venturi, and this vacuum sucks the metered amount of fuel through the orifice. You can see a couple of screws in the upper right corner of the carb on one of these screws (marked “Hi” on the chain saw body) regulates how much fuel enters the venturi when the throttle is fully open.

When the engine is idling, the throttle is almost closed (the throttle position in the photographs is the idle position). Not enough air is passing through the venturi to create a vacuum. However, there is a lot of vacuum on the back of the throttle valve (because the throttle valve restricts airflow). If you drill a tiny hole in the side of the carburetor tube, fuel can enter the tube using the throttle vacuum. This tiny hole is called the idle jet. The other screw of the pair shown in Photo 1 is labeled “Lo” and regulates the amount of fuel that passes through the idle jet.

When the engine is cold and you try to start it with the cable, the engine runs at very low rpms. Plus it’s cold, so you need a very rich mixture to start with. This is where the throttle valve comes in handy.

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When activated, the throttle valve completely closes the venturi tube (watch this throttle valve video to see it in action). If the throttle valve is wide open and the venturi is closed, the engine vacuum draws in a lot of fuel through the main or idle jets. Typically this very rich mixture allows the engine to start once or twice, or run very slowly. If you then open the choke, the engine will run normally.

Recoil starter

It contains the elements that help the engine run. Any of these elements can have their own complexities that can affect the performance of your chainsaw. For example, the rewind spring may not work properly, making it difficult for the starter rope to rewind onto the pulley.

Chainsaw Husqvarna 236 No Idling AURAMM.RU

Adjusting the carburetor on a husqvarna chainsaw


The reason for the sudden stop of the chainsaw may be incorrect adjustment of this device. There are 3 special screws on the carburetor of your Shtil361. The first of them is designated H (with its help the maximum speed is set), the second. L (regulates the idle speed) and the third S or LA (idle speed). Before starting, unscrew the third screw counterclockwise 1-1.5 turns and start the saw. If the engine does not stall, then look at the chain: it should remain stationary. If not, turn the screw in the opposite direction until the chain stops. If, when the accelerator is pressed, the saw picks up speed too slowly, then this can be adjusted with the engine running with the screw L.

How to set up and adjust the chainsaw carburetor:

Check the adjustments and adjust if necessary

Defective spark plug and spark gap

Spark plug. the only part that supplies the necessary spark to the combustion chamber. If the spark plug does not produce the spark needed to keep the engine idling, the engine will stall. Therefore, it is important that the spark plug is in good working order. In addition, there is a flame arrester that helps the combustion chamber trap the spark from the spark plug. Like the spark plug, the spark gap must also be operational.

Find the spark plug and spark arrestor on your chainsaw. Remove the spark plug and spark gap to ensure they are in good working order. The shock absorber is a fairly transparent layer of carbon clothing. If it is in good condition, you can view it. If it gets clogged, clean it up with rubbing alcohol. Check the spark plug for carbon build-up. Clean the spark plug with kerosene. If the spark plug or spark gap, or both are not in good condition, they must be replaced.

Refit both parts and carry out functional check of the chainsaw. If it still stalls at idle, go to the next step.

Chainsaw carburetor tuning steps:

Almost all carburetor models have three adjusting screws. Screw T. fine adjustment in idle mode. Screw H. setting for maximum speed. Screw L. mixture formation at low speed.

  • Adjustment of the engine for uninterrupted operation at low speeds is ensured by adjusting screw L and idle speed T. Screw L is tightened until maximum engine speed is obtained, after which it is released by 1/4, and idle speed is returned to normal by screw T. The idle speed should be such that the chainsaw does not stall, and the chain does not rotate. Each manufacturer specifies the recommended idle speed in the operating instructions, measuring the exact engine speed is quite simple using a tachometer.
  • Setting the carburetor for the correct supply of the fuel mixture at maximum speed. We smoothly tighten the screw H and check the speed according to the readings of the electronic tachometer. The setting is made on a running chainsaw. Many Echo and Husqvarna chain saws use a special tool for the L and H screws, and a standard Phillips screwdriver for the T screw
  • Checking the chainsaw in all modes after tuning.

Specialists of the company “Direct Hands” in St. Petersburg on the street. Dimitrova, 3 will perform diagnostics, service and repair of chainsaws Stihl, Echo, Champion, Husqvarna, Partner, DDE, MTD.

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