Why the chainsaw does not start Causes and methods of elimination. How the mechanism is designed
Almost all tools, both foreign (Husqvarna, Makita, STIHL, Partner 350), and Chinese chain saws, and domestic (Druzhba, Ural), are arranged similarly. Therefore, it is not difficult to find the reason why the machine does not start and stops.
There are four elements where problems can arise:
- Fuel, for which the carburetor is responsible ;
- The air which comes through the air filter;
- The spark, the quality of which depends on the ignition unit.
They all depend on each other and interact with each other. If any element is not working properly, then the saw stops working.
To begin with, all tools start differently. hot and cold. Two frequently used mechanisms are responsible for this process.
Be sure to see what is written in the owner’s manual. It says to make sure the emergency stop brake is engaged when you turn it on. But it is much harder to start a saw with a brake, so sometimes it is better not to engage the brake.
As you can see from the instruction manual, inside the body there is the fuel tank and the engine, and outside there is the saw part (guide bar with chain), the handle and the starter.
First you need to figure out exactly how the tool won’t start. For example, the saw starts, but immediately stops, or loses power, the quality of the cut.
Probably the malfunctions are caused by problems with the engine. But I wouldn’t recommend taking it apart right away. It’s better to look for the problem from the simplest option.
It is very important to consider the quality of the fuel. If the mixture is prepared incorrectly or has deteriorated over time, even reliable tools such as the Ural or Husqvarna 145, will not work. Always read the instructions for your chainsaw and ask for the correct oil proportions.
Another common problem is that the user fills the spark plug during start. If it is completely dry then it means that the fuel is not getting into the cylinder.
If you see black carbon deposits or a lot of fuel, the carburetor may not be adjusting the fuel flow properly.
If your saw does not start but immediately stops, the problem is in the carburetor nozzle or fuel filter. It might be clogged.
To check if the breather plug is damaged, disconnect the fuel hose from the carburetor and see if the fuel mixture is leaking from it.
If your chain saw will not start while hot, the problem may be with your muffler. Sometimes it gets clogged from the exhaust itself.
Quite often chain lubrication is the reason why a saw breaks down. This happens when there are clogged ducts or leaking oil lines.
Also check the tube connections on the oil pump connections for leaks.
Too bad when the failure is in the cylinder. When examining it, you can detect irregularities or chips, and this may be the cause of the problem.
Why won’t the STIHL 180 chain saw start when hot? s
STIHL 180 chain saw does not start? Prerequisites and solution!
Today the manufacturer STIHL is in a leading position among other companies that produce equipment designed for agricultural and construction. Production of this manufacturer is known not only for its high level of quality, but also a good pricing policy and capacity of its models. This is one of the most recognizable global companies.
It’s probably quite difficult to meet a person who would not have had a chain saw of this brand. But the fact that out of 10 likely 6 people exactly have them. Why a chainsaw won’t start if it won’t start. Reasons why you can’t. This is not uncommon, because STIHL chain saws are as powerful as they are elegant in design. But unfortunately, even such giants of technology from time to time break down and need some kind of repair. Now we will pay attention to one of the moths of this manufacturer, namely chain saw STIHL 180. Chainsaw does not start well in cold conditions, but chain saw does not start right away. Read about the STIHL ms 660 chain saw here. Here we go.
The engine starts, but the chainsaw stalls at idle or under load. In this case, it is often necessary to carry out the same actions as described above.
How to adjust your chainsaw depends on exactly when the problems start:
Stops right after starting:
- The fuel mixture is not mixed correctly, it contains too much oil, that’s why the octane number of the gasoline is lower than it should be, and that’s why the chainsaw works only on a blow-off or immediately shuts down.
- Carbon deposits on spark plug or improper gap between spark plug and wire.
Stops and does not work at idle rpm:
- Plugged muffler. Need to clean off carbon deposits.
- Wrong carburetor setting. No idle speed adjustment is needed on the chain saw. You do this with the L and H adjustment screws. To learn how to adjust the idle speed, see the article on carburetor adjustment.
Stops at maximum rpm and runs on suction
- Clogged air or fuel filter. Seals need to be cleaned and checked.
- The breather plug is clogged, which prevents fuel flow and makes the gasoline pump on the chain saw inoperable. Take a needle and clean the breather gently.
- Gas pump is blocked. Remove the pump and check for gasoline leakage. If leaking, replace gasket or pump.
Your chain saw does not cut under load and stops
- Clogged air filter. It is necessary to take out the filter, clean or even rinse it well, dry it and put it back.
- Wrong petrol/oil mixture proportion. Drain the fuel and mix the oil and gasoline again in the correct proportions.
Calibration algorithm and safety precautions for troubleshooting chainsaw carburetors
The carburetor adjustment is done in two steps:
For basic adjustment turn the screws H and L up to the stop and turn them back 1.5 turns. The final adjustment requires the engine to be warmed up for 5 to 10 minutes at low rpm.
The final calibration is carried out by turning the idle speed screw back until the engine reaches minimum rpm (the engine should be stable and the chain should be stationary). If the engine stops when idling, turn the screw back. If the saw chain is still in motion, continue to turn counterclockwise.
Checking the calibration is done by testing:
- Acceleration (when the gas pedal is pressed gently, the engine should quickly build up to maximum RPM).
- Maximum RPM (if the ignition fails the H screw should be loosened slightly).
- Idling (the chain should not move and the engine should rev up as fast as possible).
If the owner of the chainsaw is not familiar with the device of the carburetor and does not have the necessary tools to conduct its calibration, you should contact a specialist. The carburetor is a very complex unit, so any wrong action can lead to irreversible consequences, such as complete engine failure.
Checking the breather
The breather is a part that some chain saw owners don’t even realize it exists. However, it has a significant effect on the operation of the tool and keeps it in good working order. The breather plug is mounted on the fuel tank lid where the air circulation hole is located.
- Preventing gasoline from leaking while the saw is running.
- Correcting the air pressure required for an unobstructed flow of fuel into the carburetor.
Contamination of the breather plug causes the chainsaw to continually stall when sawing. The tool might fail to start at the startup. These consequences are due to a lack of air. due to the blockage of the hole through which it passes. As a result, the tank turns into a vacuum, which blocks the access of gasoline to the carburetor.
To recognize this problem, you need to take the following steps:
- The fuel hose is disconnected from the carburetor.
- The gasoline is analyzed: if the fuel continues to flow in a steady stream, the breather is in good condition. Uneven fuel flow indicates that the breather plug is clogged with dirt particles.
- Clean the breather plug with a needle or compressed air jet.
No hot starts on your chain saw
In those cases, when the chainsaw does not start when hot, it is necessary to carry out a visual inspection of all the main components of the chainsaw. The inspection should start with the spark plug. Check the spark, inspect the surface of the spark plug electrode, these actions will help establish the direction in which to look for the problem.
Trouble in the ignition system
If you examine the spark plug, it is found that it is wet and the spark formation on the contacts does not occur, it means that the problem should be sought in the ignition system, examine the coil, check the gap between the flywheel and coil contacts. You can also check how firmly the cap of the spark plug is seated on the spark plug and the spark plug itself. Try replacing it with a new one.
Problems in the fuel system
If the inspection reveals that the spark is there, but the spark plug is dry, it means that there is a problem in the fuel system. It is necessary to start check it with the fuel filter. Next, you need to inspect the fuel hose and its attachment to the carburetor, pay attention to fuel leaks from the carburetor and the presence of gasoline in the air filter housing. Proceed to the removal of the carburetor expedient only if visual inspection did not allow to determine the cause of failure.
A typical sign of fuel system problems is an excessive amount of fuel in the engine cylinder. This is usually indicated by an excessively wet spark plug and the presence of spark on the spark plug contacts. If this happens you need to turn the chain saw upside down so that the spark plug hole is pointing downward. If gasoline is leaking from the cylinder, it means that the chainsaw will not start if the fuel overflows into the engine.
“The engine is running low on fuel, sometimes due to improper carburetor adjustment or carburetor malfunction.
With the process of adjusting the carburetor, you can get acquainted with the example of Champion 254 saw, by watching the video instruction.
The chain saw doesn’t start when it’s hot
In those cases, when the chainsaw does not start when hot, you need to conduct a visual inspection of all the major components of the chainsaw. The inspection should start with the spark plug. Check the spark, inspect the electrode surface of the plug, these actions will help to determine the direction in which to look for the problem.
Trouble in the ignition system
If when inspecting the spark plug, it is found that it is wet and spark formation on the contacts does not occur, this means that the problem should be sought in the ignition system, inspect the coil, check the gap between the flywheel and coil contacts. You can also check how tightly the cap of the high-voltage wire sits on the spark plug, and the spark plug itself. Try replacing it, with a new one.
Problems in the fuel system
If on examination it is found that the spark is still there and the spark plug is dry, then there is a problem in the fuel system. It should be checked first with the fuel filter. Next, you need to inspect the fuel hose and its attachment to the carburetor, pay attention to fuel leaks from the carburetor and the presence of gasoline in the air filter housing. Start removing the carburetor only if the visual inspection did not identify the cause of failure.
A typical sign of a problem with the fuel system is that there is too much fuel in the engine cylinder. As a rule, the signs of this are excessively wet spark plugs and the presence of spark on the plug pins. In this situation, turn the chainsaw upside down so that the spark plug hole is facing downward. If there is gasoline leaking from the cylinder, then the reason why the chainsaw will not start is that the fuel is overflowing into the engine.
“Pouring” fuel, sometimes due to improper carburetor adjustment or carburetor malfunction.
You can learn how to adjust the carburetor, using Champion 254 as an example, by watching the instruction video.
The next most popular cause of saw failure is clogged filters. Cutting tool consists of two filters: an air filter and a fuel filter. These parts are responsible for different processes, but equally contribute to cleaning and trapping foreign particles.
To check the operation of the fuel filter, proceed as follows:
- The fuel line is disconnected from the carburetor.
- Inflate the fuel system.
- Checking the fuel intake.
- If petrol does not come with a weak pressure (or does not come at all), the fuel filter is clogged.
- All gasoline is evacuated from the tank.
- The filter element is disconnected with a hook.
- Cartridge is cleaned. If you want you can skip this step and replace the clogged filter with a new one.
- The saw is put back together.
Filters do tend to get dirty over time. That’s why chain saw owners with experience clean the filters as a preventive measure. How often you do this depends on the environment in which you work. If there is a lot of dust in the workshop, the cartridges get dirty faster.
When the air filter becomes clogged, the saw’s engine begins to run erratically. In practice, this factor leads to intermittent shutdown of the saw or difficulty in starting. The absorbent material accumulates dust and dirt, the large volume of which leads to complete impenetrability of the diaphragm. When the air stops flowing into the system, the gasoline becomes too enriched.
The air filter is cleaned in a similar manner:
- The chainsaw is opened and the air filter is removed.
- Removing the filter prevents dust particles from entering the carburettor.
- The cartridge is disconnected and cleaned of accumulated dirt.
- The surface of the filter is treated with detergent.
- The element is thoroughly dried.
- The saw is put back together.
If the chainsaw spark plug was still filled, and you do not want to wait for the fuel to drain off, there is a fairly efficient and quick method of cleaning.
- If the repair takes place in the field, the saw is installed on a flat surface (in the workshop everything is easier. the table to help), then pulled the BB wire from the plug and with a wrench takes out the plug, its electrodes are wiped dry. In doing so, the circuit breaker must be engaged.
- The air filter cover is unscrewed and cleared of dirt.
- The control lever is then set to the minimum throttle position and the starter cord is jerked up to 10 times, but not less than 5. Thereby, the combustion chamber is cleared of excess fuel.
- Putting back the air filter, installing the spark plug and connecting the wire, you should pull the starter cord a few more times. The throttle valve must remain open at the same time.
If these actions are performed correctly, the saw will “come back to life”.
Most chainsaw owners have filled the spark plugs more than once, and they themselves have returned the tool to functionality more than once. Do not be afraid of this problem: straight growing hands and availability of the user manual will help without going to a specialized center to continue using the tool.
If after a thorough inspection of the basic assemblies of the grass trimmer the cause of the malfunction of the device has not been found, then you need to carefully inspect the engine and carburetor. In this case, there are three key problems that occur most frequently at once:
- Natural wear of the installed carburetor gasket. The only logical way out of this situation is to replace the faulty part.
- Debris and carbon deposits in jets or passages. Only factory flushes or a normal compressed air stream from a compressor can be used for cleaning. It is forbidden to use wire and sewing needles, because one wrong movement can seriously damage the passage section.
- Loss of former tightness. For a thorough check of this indicator it is necessary to use a classic household tonometer, pre-installing a suitable manometer. It is necessary to monitor the indicators: if any fluctuations have not been fixed, then everything is fine, but when the pressure gradually drops, then some part in the carburetor has failed.
If the carburetor used is good, the gasoline grass trimmer does not start because the piston group has failed. If during the checkup you find any unusual chips, bends or scratches, it is time to replace the part. Experts recommend replacing the piston rings. If by swinging a mounted crank arm you get a little play, then the rings need to be replaced, but it is better to let a professional do it.
Why the chainsaw stops on load?
Chainsaws equipped with high-speed engines quite often refuse to work when the load is increased. If the chainsaw works fine when idling, but shuts down under load, this indicates a number of possible malfunctions, such as
- the fuel filter is clogged;
- faulty or clogged gas tank;
- The quality of the fuel mixture used does not meet the unit’s requirements.
If the problem is with the filter or the gas tank, we recommend that you replace it with a new one to avoid future problems. If even that did not help to fix the situation, and gasoline equipment and continues to suddenly cut out before the beginning of fruitful work, it is necessary to prepare a new fuel mixture, using only high-quality gasoline with a high octane number. The proportion of oil and gasoline has to be strictly maintained so that the engine can generate the necessary power even under sufficiently high loads.
What to do, if the chainsaw picks up speed and stops?
This situation is very similar to the previous one, the only difference is that the chain saw doesn’t demonstrate any high rpm, and here it initially produces rpm but doesn’t hold it. The most common reasons for a chainsaw to shut down in heat are clogged filter parts or a faulty fuel pump.
The air filter should be rinsed and dried periodically before re-installing it, and the fuel hoses should be checked for leaks and replaced with new ones if necessary. Each part has an expiration date, so do not be surprised that the gasoline pump will stop holding fuel in itself and begin to leak, which is also worth taking into account when troubleshooting such equipment.
How a carburetor works
Most often, the problems in the carburetor can be eliminated with their own hands. However, this requires an understanding of the basic principles of its operation.
How a carburetor works
The principle of operation of the carburetor:
- After starting the engine, the flap opens, through which air enters the carburetor;
- In the air aerodynamic tube and the float chamber, a zone of reduced pressure is created, as a result of which the air is sucked in through the diffuser;
- The intensity of the air intake varies, depending on which position the flap is set;
- At this time, gasoline flows from the tank of the chainsaw into the diffuser, where it mixes with the air;
- The so-called fuel-air mixture is formed, which is routed through the intake ducts, directly into the combustion chamber;
Carburetor adjustment period
Before we take a wrench and a screwdriver in our hands, let’s see if we can improve the chainsaw’s performance by adjusting the carburetor.
Adjustment of the carburetor is necessary if:
- Worn or loose adjustment screws. the reason for this may be as a factory defect, and vibration, which is accompanied by the work of a chainsaw. With this malfunction, it is possible to adjust the carburetor without removing it from the chainsaw;
- The most common cause of improper operation of the carburetor, is contamination. The blame for this lies with the owner of the unit. Obviously, the owner did not pay enough attention to cleaning and care of the air filter, and the quality of fuel looked through the fingers. In this case, adjustment is not enough. Now you will have to completely disassemble the unit, blow all the channels, wash it, remove scale and scale, and then assemble and adjust it;
Cleaning the air filter
- A new chainsaw does not need adjustment. Over time, however, serious wear and tear occurs in all components, including the engine. Your chain saw does not run well at high rpm and under load. The factory settings don’t work anymore. In this case, you can adjust the carburetor to other parameters, however. this is a temporary solution, one way or another it is necessary to repair the engine;
Restore the work of the tool
To get your STIHL saw working again, it doesn’t matter if it is the Urals or STIHL, you need to know where the breakdown is located.
First we check and change the unsuitable fuel mixture. If it still won’t start, then you can do the following steps.
The problem is the spark plug. pull it out and dry it. In no case should not pierce it, because this will lead to malfunction of the part. After a drying time of about 30 minutes you can put the spark plug back in, making sure you have not left any fuel in the plug.
It is also possible that the spark plug is simply broken, so it is better to have a spare to rule out the cause.
Another reason why the tool does not start and stalls is bad contact between the spark plugs and the high-voltage wire. If everything is okay here, but there is still no spark, the ignition unit itself may be broken. This fault can only be repaired by replacing it.
You should check and clean the air filter from time to time. If you haven’t checked it since you bought it, it may be clogged with dust and cause a malfunction.
The STIHL 180, Ural or Partner 350 often suffers from a clogged breather valve which can lead to malfunctions. To clean it, you can use a sewing needle.
The STIHL 180, Druzhba, Ural and Husqvarna 142 models are sometimes blocked and should be checked and cleaned.
If the problem is with the carburetor, it is best not to try to repair it unless you have the expertise to do so. Best to call in an expert.
If after checking and correcting these problems your chain saw still fails to start, the problem is probably in the cylinder group.
When you saw during the inspection damage and chips on the nodes of the piston or cylinder, these elements will have to be replaced.
If the chainsaw is broken by leaking tubes, it is most likely because the chain is not getting enough lubricant. To fix the problem you need only to replace the tubing and seal the joints with sealing compound.
Because machinery parts don’t last forever, you’ll have to replace them periodically. To find out how long a part lasts, you can check its manual.
Here’s a look at the most common model that breaks down
Let’s take a closer look at the STIHL 180’s problems:
- A clogged carburetor or fuel filter. These are the most common problems and can be fixed very easily after cleaning. Sometimes the filter has to be changed;
- Plug change;
- Sometimes the cylinder or oil seals need to be replaced.
STIHL saws are rugged and dependable enough to do the job yourself. In fact, the same applies to Partner, Ural, Makita and Husqvarna models.
If you discover a problem with your chainsaw, start small and work out the causes of the problem as you go along. It is easy to fix these problems yourself. But if the breakdown is serious, and you do not have enough experience, then it should deal with a specialist.