Stihl Ms 180 Stalls On Load
Reasons why chainsaw starts and stalls
A chainsaw has long been not a luxury, but a necessary tool for those who have a summer cottage or home ownership. But, like any other technique, this tool has the ability to fail, despite the simple device.
The classification of major faults includes:
- Complete lack of engine plant
- Engine starts and stalls
- Unstable tool operation
- Work stop at load
- Power loss.
If the chainsaw does not start at all, the reason may be as follows:
- Manufacturing defect
- Lack of fuel
- Problems starting the ignition system
- No spark from spark plugs
- Poor fuel mixture
- Clogged carburetor
- Problems with high voltage wire
- Lack of compression.
Why chainsaw starts up and stalls, what to do in this case? It is necessary to consider in detail the reasons for this.
Chainsaw Starts and stalls: reason
The reason that the chainsaw may stall right after the factory is due to a malfunction of a certain part of the equipment.
- The most common reason why the chainsaw is wound up and stalled may be the low fuel level in the tank. This can be confirmed by stopping the tool when tilted, when the remaining fuel accumulates in a certain place in the fuel tank. With low-quality fuel, a problem with the operation of the chainsaw may also occur, in which case it must be completely replaced.
- Clogged breather, which significantly reduces fuel consumption to the engine.
- Insufficient contact of the cap of the wire with the candle, which leads to strong heating of the insulator of the candle. Contact deterioration may occur due to mechanical shear or carbon deposits.
- Damage to spark plugs.
- Muffler clogging, due to which the exhaust gas output deteriorates, leading to engine shutdown. For this reason, the chainsaw may start and stall at idle. Sludge in the silencer can also occur due to poor fuel or improper use of the tool.
- Poor carb adjustment.
- Piston group breakdown
- Problems with the fuel filter or pump. In this case, gasoline may leak through the pump or leak poorly through the fuel filter to the carburetor. As a result, a chainsaw starts up and stalls with increasing speed.
- Air filter is dirty. Problems with this element of equipment lead to the fact that, with increased loads on the engine, it simply can not cope with them due to clogging and stops. A similar result is also obtained with an increase in speed.
- Short circuit due to lack or insufficient lubrication, as well as a problem with the chain brake.
Any tool can break and the Stihl MS 180 chainsaw is no exception. Today we’ll try to understand issues such as: why the chainsaw stalls at an increase in speed, also at idle and at full speed. Let’s consider the options for diagnosing and troubleshooting related to this behavior of the Stihl 180 chainsaw.
Why the chainsaw stalls when you press the gas
Suppose a chainsaw normally idles, but with a sharp pressure on the gas stalls. What could be the reason? It is immediately clear that it is not a matter of ignition (the absence of a spark), because if there was a malfunction in the ignition and the absence of a spark, the tool would simply not start. So the fuel system remains.
There are a lot of fuel system malfunctions and to determine the exact reason why the Stihl 180 chainsaw stalls when you press the gas, it is necessary to carry out its full diagnosis. We recommend reading about common Stihl 180 chainsaw malfunctions and their troubleshooting.
The first thing to check is the fuel filter.
In some cases, a dirt-clogged filter is unable to pass through the fuel mixture in sufficient quantities. Accordingly, there is a fuel shortage in the system, which leads to the fact that when you press the gas chainsaw, the fuel burns out, and a new one does not have time to arrive, as a result of which the Stihl chainsaw stalls. Also, with a clogged fuel filter, a noticeable drop in the power of the chainsaw at maximum speeds may be observed, but this is with little pollution.
On the pages of the World Wide Web, you can find information that the Stihl 180 chainsaw may stall due to severe contamination of the air filter. I would like to refute this not entirely correct information, and to inform that the Stihl MC 180 carburetor is equipped with a compensator, which is designed and installed in order to take the air necessary for the normal operation of the Stihl 180 chainsaw, bypassing the contaminated air filter. Of course, power with a clogged air filter will drop a little, but it certainly will not stall. Also, power may drop due to piston wear, a Stihl MS 180 piston chainsaw repair will already be required.
One of the reasons why the chainsaw does not develop speed when you press the gas, but instead stall, is a carburetor malfunction. Let’s say the Stihl 180 saw worked properly, and then it was put on for a long time and did not use it. After it was started, and at idle it works well, and when you press the gas it can stall. Why does it stall? The reason is a stuck carburetor valve nozzle. Of course, this is not 100%, but the probability of such a malfunction is high. We recommend reading the article about the device and repair of the Stihl 180 carburetor.
In order to check the nozzle, it is necessary to remove the carburetor and disassemble it. To remove, it is necessary to unscrew the two nuts securing the air filter and the carburetor, then remove the air filter and the engine control lever, while disconnecting the throttle control rod from the carburetor. Next, you need to slightly pull the carburetor towards yourself, and disconnect the fuel supply hose.
It is necessary to remove the fuel hose as carefully as possible, and prepare a plug for it in advance, since fuel should flow from it.
After removing the carburetor, it must be purged and cleaned of dirt, only after that the carburetor can be untwisted.
It is necessary to unwind the cover of the main carburetor chamber, this is the one on which the compensator is mounted on top. Then with a bolt of 8 mm and a length of at least 50 mm. We knock out the valve.
It is necessary to knock out the valve by installing the carburetor on a wooden stand, this will ensure its protection against damage to the body.
After the nozzle is removed, it can be purged using a compressor. The valve must allow air to flow in only one direction, if the valve can be blown freely in both directions, it means that it is defective and must be replaced with a new one. Assemble the chainsaw after the valve has been repaired, following the reverse disassembly sequence.
You can see clearly how the carburetor is being repaired, or rather how to knock the valve nozzle out of the carburetor body correctly by watching the.
Another common reason why the saw may stall with increasing speed, air intake in the carburetor. This can only be checked with a special tool, but it is worth noting that if preventive work with the carburetor has not been carried out for a long time, then a new set of gaskets can be installed in the carburetor. In some cases, this helps to solve the problem with its depressurization.
When disassembling the carburetor to replace the gaskets, you need to carefully examine its needle valve, press the rocker arm and check its lifting. Sometimes, especially after the Stihl chainsaw has stood for a long time with fuel in the carburetor, the needle may burn to the carburetor body and not perform its functions. Simply put, the needle valve will not let the fuel mixture through. In this case, the saw will not work.
Why stalls idling
The first and most common cause of this malfunction is the incorrect carburetor adjustment. You can adjust the idle speed yourself, for this you need to have a Stihl adjustment screwdriver, which is supplied with the unit. The adjustment hole is located on the right side of the Stihl 180 saw on the handle and is indicated by “-” and “”.
If the Stihl chainsaw does not keep speed and stalls idling, you can be almost 90% sure that it has a violation in the fuel pump system, as a rule, it is the air leaking into the crankcase through the gasket of the sump, or, much more often, through the oil seals crankshaft. Air suction reduces or even completely stops the impulse, which is supplied through special channels to the fuel pump of the chainsaw. As a result of this, the Stihl 180 chainsaw does not receive the required amount of fuel and stalls at idle.
Diagnostics can be done using a special device called a vacuum gauge.
The second way to check the efficiency of the oil seals is to pour gasoline into the engine crankcase and look at them if the oil seals pass gasoline, which means they cannot provide normal pressure in the crankcase, which will make idling impossible. And when working at high speeds, with leaky seals, there is a possibility of jamming of the crankshaft bearings.
The algorithm for checking the crankcase and Stihl 180 oil seals for leaks is as follows:
- The top cover is removed.
- The air filter housing and the carburetor are dismantled.
- The handle of the chainsaw is removed.
- The starter is untwisted and removed.
- The side cover and drive sprocket are removed from the opposite side from the starter.
- A piston stop is installed in the spark plug hole or a cord from an old starter with knots imposed on it is stuffed into the cylinder.
- The flywheel and clutch are unscrewed, after which the parts are removed. It is worth knowing that the clutch of the chainsaw has a left-hand thread and is unscrewed clockwise.
- The gear wheel of the oil pump drive is removed.
Having disassembled the Stihl MS 180 chainsaw, you can see the seals, after that it is necessary to fill the crankcase with gasoline and to check the leakage. It is possible to fill the crankcase through the fuel window in the cylinder; for this, the piston must be raised as high as possible. If leaks are found, defective oil seals must be replaced, or the pan re-sealed. Stihl 180 can be assembled following the reverse sequence of the algorithm.
Why stalls at full speed
You can often hear the question of why the chainsaw stalls at full speed. There may be several reasons. First, you need to consider how exactly the saw stalled. Let’s say the tool worked fine and suddenly, for no apparent reason, it suddenly died out and the starter does not crank. In such a situation, you can be 100% sure that the chainsaw is stuck and you need to proceed with its overhaul.
The second situation is when the Stihl 180 chainsaw worked fine, then gradually in a short time it lost power and died out, while overheating of the cylinder is observed. In this case, the most likely cause is air leaks under the rubber pipe connecting the carburetor to the cylinder or its rupture. The mixture was leaner, resulting in overheating. You can eliminate the cause by changing the nozzle.
If the Stihl MC 180 chainsaw stalls at idle, does not gain power when you press the gas or stalls at full speed, it is necessary to diagnose the fuel system and check the crankcase for leaks. You can do it yourself, but you need to have certain skills. If you are not familiar with push-pull saws, it is better to turn to specialists, because this technique is rather capricious and any mistakes are expensive.
The light and compact model of the tool is used for domestic purposes, but despite the optimized performance, the Stihl chainsaw sometimes does not start. The problems are manifested in the fact that the engine turns on and stalls, works unstably, cannot develop the required power or unexpectedly gains high speed.
Why the Stihl chainsaw won’t start
For a preliminary diagnosis of the causes, the operation of the gas pump, the appearance of the spark plug, fuel intake, carburetor functionality and filter condition are checked. Pay attention to the performance of cylinders, pistons, muffler, crankshaft bearings. After preventive measures, they try to start a chainsaw. Inadequate lubrication of rubbing parts also becomes a factor in poor performance.
Lack of spark
Spark test on spark plug. The functioning of an element is influenced by various factors. When testing the mechanism, the causes are identified:
- Insufficient carburetor adjustment;
- Large oil in gasoline;
- Clogged fuel and air filters.
Due to the work in such conditions, deposits accumulate on the contacts of the candle. Subsequent corrosion of the conductors causes no spark in half of the faults. This is because the gap between the modular contacts changes. To test the sparks, do the following:
- The tip of the high voltage cable is removed;
- The candle is twisted;
- The tip is put in place;
- The candle is propped against the cylinder with a wide end;
- Start the starter.
If during start-up a bright spark resembling lightning appears between the electrodes, the ignition unit is in good condition. If there is no flash, they clean the entire element and set the gap between the conductors. Sometimes there is no gap between the flywheel and the ignition coil. When the flywheel is rubbed, scratches are visible on its exterior.
Malfunction of the ignition coil
The module or coil is not disassembled, its suitability is difficult to identify without testing devices. Modern ignition systems are durable, lightweight and small in size. They are characterized by almost failure-free functionality. Chainsaw malfunctions due to the ignition coil can be fixed by yourself.
Test the outlet wires for damage (including internal) that occurs due to vibration leading to friction. If no cracks are found, then the ignition coil needs to be replaced. Sometimes a malfunction of the module is indicated by a faint, barely noticeable flash when the saw is heated. This is due to an increase in coil temperature, which leads to an increase in transistor resistance.
The peculiarity is that at the beginning of the work a spark can appear, but after prolonged use it becomes dull and disappears. Modern ignition coils in the home workshop are not repaired, therefore they are replaced with suitable elements.
After twisting the candle on its surface, a wet coating is detected. This indicates an excessive supply of gasoline to the combustion chamber. For this reason, the tool does not work or stalls, because the fuel does not ignite.
Another inhibitory factor is clogging of the breather, a small hole in the cap of the gas tank. It is cleaned with a needle, otherwise the Stihl MS 180 chainsaw will not start. To determine the wrong fuel supply, carry out sequential actions:
- Remove the candle;
- 2 cubes of gasoline are poured into a hole in a candle with a syringe;
- Put the ignition device in place and put on the cap of the high-voltage wire;
- The lever is moved to the hot start position;
- Pull the starter handle a couple of times.
If the tool starts and immediately stalls, then the fuel line is tested further. Check the gasoline filter, the surge from the crankcase, the integrity of the septum in the pump when unscrewing the cover.
Crankshaft bearing failure
With bearing defects, a slight play is felt. To identify it, the flywheel of the Stihl MS 180 saw is shaken from one side to the other. The movement indicates that the flywheel is shifted towards the electrodes by its own magnets, as a result of which there is no spark. To remove the mechanism, remove the cutting element, remove the filter cover and clutch. For the crankshaft stopper, remove the manual starter cover and tighten two bolts.
The clutch is unscrewed using a key clockwise. Remove the drum with an asterisk, change the old clutch and spin it all the way. Lock the crankshaft so as not to break the starter. The mechanism is going in the reverse order. To tighten, the brake lever is tilted forward, the tool is turned on, then removed from the brake.
Rarely, bearings with defective bearings are detected (the diameter of the holes in the cage is increased). To determine, disassemble and measure using a micrometer. A broken knock indicates broken bearings. In this case, urgent repair is required, because if the integrity of the crankshaft is violated, the piston group and cylinder will fail.
Fills the spark plug
In this case, the spark is not able to ignite the fuel, which in large quantities enters the furnace for burning a combustible mixture. If the candle is filled, then the carburetor is defective or the cold engine does not start correctly. The engine is purged, the procedure is performed with the ignition turned off and far from an open flame. To ensure ignition of the fuel at the time of start-up, clean the mechanism:
- Unscrew the candle, wipe it dry, dry for half an hour;
- A large layer of carbon is removed by a file;
- Between the contacts regulate the gap;
- The tool is turned upside down and the gasoline is drained;
- In this position, the starter is pulled several times (to remove residual fuel);
- Reassemble in the reverse order.
Stihl chainsaw stalls: reasons
If the tool turns off immediately after start-up, it means that some device or part has broken. To determine the cause, they test the mechanism on their own or in service workshops. Sometimes the reason that the mechanism starts up poorly is the incorrect maintenance of the saw:
- Insufficient gasoline;
- Poorly prepared fuel mixture;
- Poor lubrication quality;
- Silencer clogged by combustion products;
- Unregulated carburetor;
- Air filter obstruction;
- Malfunction of the piston or cylinder.
When you press the gas
Sawing units are idling, but the chainsaw stalls when gas is pressed, because the load increases. The tool is heated before use, driving the engine at idle for a minute. If this is neglected, the motor stops after pressing the pedal. Other reasons may include:
- A clogged or unregulated combustible fuel mixing unit;
- A clogged air filter does not provide the desired air flow with increasing load;
- Contaminated gasoline filter does not pass the required amount of the mixture;
- The wall of the cylinder and piston rubs.
The low octane number of the fuel causes the brake, because this circumstance does not allow the motor to achieve the required power with increasing load.
Violation of the functionality of the fuel assembly system leads to air leaks. In this case, the unit stalls at idle and does not hold their number. An additional suction reduces the air pulse to the fuel pump and passes through the membrane of the sump or crankshaft oil seals. Diagnostics is done with a vacuum gauge.
Cessation of engine cold operation occurs for other reasons:
- The candle channel contains an excess amount of a combustible mixture;
- The gap between the tip of the candle and the high-voltage cradle is not adjusted;
- Power supply failure.
The seals are checked by pouring gasoline into the crankcase, the leak is visible visually. This means that the engine does not work at idle, and at high frequency, leaky seals will cause the bearings to seize. In case of leakage of elements they are replaced with new ones and sealing is carried out.
At full speed
Sometimes the engine stalls after normal operation. To establish the cause, pay attention to related circumstances:
- The motor stalls in the middle of work for no apparent reason. The starter is stationary and does not turn. So, the tool is jammed and needs urgent repair.
- During normal operation, power decreases in a short time and the engine stops, the cylinders are overheated. The situation indicates the occurrence of air leakage under the rubber pipe between the carburetor cylinder, possibly due to a gap. Air depletes fuel; a nozzle replacement is required.
Not gaining momentum
Many systems of the mechanism are involved in the launch, so the loss of speed of the Stihl chainsaw after idling can be a consequence of various factors. Confident idling and interruptions in the engine under load can occur for the following reasons:
- Engine resource output;
- Wear, deformation and corrosion of the piston group;
- Malfunction of the ignition coil or spark plug;
- Imbalance of carburetor screws.
If the tool does not develop revolutions, then the conductivity of the hole in the fuel tank cap is broken. The occurrence of vacuum does not provide the required amount of fuel, because the engine does not gain the required power. Turnovers are reduced with the accumulation of carbon monoxide in the muffler, and it is difficult to remove gases from combustion.
Does not slow down
The tool quickly reaches its maximum speed and power does not decrease. This situation is explained by the fact that:
- The throttle does not work due to the weakening of the spring or traction element;
- Intermittent failure of the toggle switch;
- No corkscrew on the axis of the throttle;
- Clogged carburetor;
- The fuel hose and gasoline filter are not working properly.
What to do
The power tool is operated according to the manufacturer’s instructions. Only after checking the chain tension does the unit start up. At the same time, the filling of the tanks with a combustible mixture and oil is controlled, the device is securely fixed in your hands. If, when all the rules are followed, the mechanism refuses to work, then the Stihl chainsaw is repaired.
How to start a Stihl chainsaw: instructions
The tool manufacturer took all measures and developed a manual, thanks to which the mechanism starts conveniently. The user will protect himself from injuries if he performs the proposed frequency of actions:
- The ignition is switched on and the engine handle is set to the lower position. Atmospheric intake from the air filter is blocked by a carburetor damper. To start the chainsaw correctly, the throttle membrane must be open to enrich the combustible mixture.
- The lever is set to the start gas position. The starter twitches several times until the first spark appears. If the flash passes, the instrument is ready to start. The mechanism operates at high speeds due to the closed throttle membrane. To transfer it to the idle regulation, a gas trigger is pressed and a rhinestone is released. The number of revolutions quickly normalizes.
- The Stihl MC unit as standard is not equipped with additional devices to start a light chainsaw.
Before commissioning, tool maintenance is performed. In order for the idle adjustment to be effective, they do the following:
- Carburetor cleaning;
- Flushing the engine;
- Air filter cleaning;
- Warming up the motor.
To adjust the mechanism at idle, the appropriate adjusting screw is used. Its rotation depends on the required setting:
- In standard setup, the screw is turned counterclockwise to the position where it will turn tight. After that make 2 circles in the direction of the arrow.
- If the saw operates at low speeds, then the screw is turned clockwise until the moment when the chain starts to move. Then do half a circle in the opposite direction.
- At high frequency, the regulator is turned counterclockwise until the chain stops. After this, the rotation is continued for another half revolution in the same direction.
It will not be possible to adjust idle operation if there is air leakage into the engine through a gasket, acceleration pump, oil seals or for another reason.
Gasoline engines are equipped with an ignition system that ignites the fuel. The time the flash occurs affects the operation of the motor. With mass production in the factory, the ignition adjustment of the chainsaw is not done. On the corresponding rotating elements, labels are set, which, when configured, are combined. 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 undamaged, 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 discrepancies are detected, the ignition unit is changed to a workable device.
The coil may become unusable due to vibration when the tool falls or hits, so work carefully.
Replacing crankshaft bearings
To begin with, the compression is measured, if it is not there, then the reason lies in the breakdown of the piston group.
The required pressure in the cylinder should be 8 atm, if it is lower, then the cylinder and piston, rings, crankshaft bearings may have worn out.
To find out the state of the piston system, you need to completely disassemble the saw and remove all the main components of the mechanism:
- Dismantle the headset, remove the cover on the bus;
- Remove the tire guide and tool chain with the key from the kit;
- Remove the air filter, remove the spark plug;
- The piston stopper is fixed in place of the candle to fix the crankshaft;
- The clutch is removed, then access to the clutch system is opened.
Rings with bearings inspect, identify defects. Replacement can be carried out independently, which will require repair skills, or take the tool to a specialized workshop. Assembly is done in reverse order.