Chainsaw won’t start, now what?
A chainsaw can be a very useful tool for homeowners and professionals alike, until it stops working! When your chainsaw won’t start, it can cause a setback with your project and could even set you back financially for repairs. In this chainsaw starting guide you’ll learn the common problems that can arise with chainsaws as well as possible solutions.
For many users, once a chainsaw stops working it’s a sign that it’s time to toss it and just venture out to get a new one. It may be past its warranty and some owners often feel like it’s worth buying a new one rather than paying for the repairs. However, there are simple solutions you can do yourself that might get your chainsaw running again at very little to no expense while giving you a few more years of use.
Chainsaw : Common Starting Problems
Air Filter / Spark Arrestor
| You can’t have combustion without oxygen. Check to see if your air filter is clogged — If yes, clean it. Replace if it’s worn out. |
| Is your spark arrestor clogged? If yes, clean. Replace if broken. |
Spark Plug Problems
| Check your spark plug. Does it spark? Check by holding the rubber boot of spark plug and grounding the other end on the metal of the engine. (video below) |
| If you don’t have a spark, clean or replace spark plug. |
VIDEO | How to Check for A Spark — Safely
Compression Problems
| Maybe you have a compression problem. |
| Place your chainsaw on the ground, and slowly lift it with the starter rope. If you have good compression, this will be easy. If the rope begins to extend as you move upward, you have low compression. |
| Likely causes : crankshafts seals leaking air, piston or piston rings. |
Fuel problems
| Has your chainsaw been sitting for awhile? Your fuel may be bad. Replace withe proper fuel mixture. |
| If you’re sure the fuel is good, check the fuel line for cracks or visible leaks. |
| Next, check the fuel filter. Is it blocked? If yes, use a fuel cleaner. |
| If the fuel filter is damaged, replace it. |
Video | What to Check when your Chainsaw Won’t Start
The Basic Mechanics of a Chainsaw
In order to understand what might be causing your chainsaw not to start, it’s a good idea to have a basic understanding of the mechanics that go on inside. Chainsaw models will differ from one to another and while they often have different features and types from gas to electric, they all operate on a similar concept.
No matter what type of chainsaw you have, one thing that is common in all of them is that they are operated by an engine. They also all consist of a blade made up of sharpened steel alloy that is built within a chain (hence the name, chainsaw). Inside the motor are gear wheels that turn the chain which allows it to run along the guide bar as you drive through tree limbs and lumber. A piston within the engine moves in and out of the cylinder and pushes on a connecting rod which results in the crankshaft turning gears that are connected causing the chain of the saw to spin along the guide bar.
The cylinder in the chainsaw’s engine works similarly to a cylinder in a car; the fuel from the saw’s gas tank mixes with air through the carburetor where it gets passed through this cylinder and becomes ignited by a spark plug. It then burns, releasing its energy as it pushes the piston back and forth.
Understanding how your chainsaw works can provide clues as to what the problem might be when it stops working. There are several things that can go wrong even in the highest quality models over time, but knowing what to look for will give you an idea if it’s something you can fix yourself or will need a professional to look at.
Starting Your Chainsaw
First thing’s first, you must ensure that you are actually starting the chainsaw correctly. For beginners that have had little or no prior experience using one of these power tools, a lack of knowledge on how to start a chainsaw the right way could lead to serious problems.
Video | How to Start A Husqvarna Chainsaw
Step 1 : Place it on a flat ground
The first thing you want to do is be sure to place the chainsaw on a flat surface such as the ground. Remove the bar cover, if you haven’t already.
Step 2 : Activate Chain Brake
The next thing you want to do is activate the chain brake, found on the top handle, by pushing forward on it. This keeps the chain from rotating on the bar as a safety measure.
Step 3 : Engage the Smart Start Decompression
Some models feature a decompression control (known as Smart Start in some models) that aids in the startup of your chainsaw. If you’re using a model equipped with this feature such as a Husqvarna chainsaw, push in the decompression valve.
Step 4 : Press the Fuel Pump
Another added feature some models are equipped with is a fuel pump or a primer bulb. Press the button a few times until you can visibly see the fuel for easier startup with fewer pulls to start the machine.
Step 5 : Pull Starter Rope
With the chainsaw still securely on a flat surface, place your right foot on the rear handle of the saw while holding the top handle firmly with your left hand. Be sure the cutting attachment is not in contact with the ground before you begin pulling the starter. Use smooth, quick motions to pull the starter.
Step 6 : Push Throttle Halfway
Push the throttle at halfway and pull the rope until the saw is running. When the engine powers on, you can accelerate it to keep the engine active. You may need to move the Master Lever to open up the choke if the engine starts up then dies right away. When you have successfully started the chainsaw and have it running, touch the throttle button once again to reset the Master Control to its normal setting.
Here are some things to look out for that can cause you to run into problems when starting:
- Cold weather -- when the engine is cold either from cold weather or left not running for a few hours it can make startups more difficult. This is one of the common reasons why a chainsaw won’t start in cooler climates. If this is the case, find the choke and pull it out as much as possible.
- Holding the throttle too long -- when the chainsaw starts up, you will hit the throttle briefly one time to achieve idle speed. Sometimes a chainsaw will sputter right after it starts, which you can help to inject more fuel into the engine by briefly tapping the throttle a few times. If the throttle is held too long, it will stop the engine.
- Stubborn starters -- in some models, the starters will require more effort to get it going than others. A bigger chainsaw engine will have a greater starter cord tension that will require more effort. Give it a few tries at pulling the starter before you give in assuming something is wrong with the saw. Stihl chainsaws are equipped with an Easy2Start system that reduces cord tension for this very reason.
Troubleshooting | Starting your Chainsaw
You’ve ensured that you have done everything right but your chainsaw will not start no matter how many times you pull the starter. There are a few possible causes that you can easily check and resolve on your own. Sometimes all you need is to replace needed parts that may be broken or not functioning correctly. These can be purchased by the manufacturer, online, or even hardware stores typically at a fraction of what it would cost you from a mechanic. Here are some common areas to check that can cause your chainsaw not to start:
The spark plugs
One of the first things you should check is if the saw’s plug ignites a spark. The spark is responsible for initiating combustion within the cylinder where the air-fuel mixture is ignited. It is very common in most chainsaws for the spark plug to corrode over time from wear and tear. To check if the plug gives off a spark first remove it, then use a plug wire to make contact with the metallic part of the engine and observe for the electrodes to produce a spark. If it doesn’t, you can simply clean it using a steel brush to gently remove the corrosion. If it still doesn’t ignite after cleaning it, you can replace it with a new spark plug.
The Ignition Coil
A defective ignition coil can also be the culprit when an engine fails to start. This is what sends the voltage to the spark plug while the chainsaw is running, so if you have checked the spark plugs and tried cleaning and/or replacing it with a new one but still have starting issues, the ignition coil might be to blame. Use an ignition coil tester to determine if it is defective. If it is, you will need to replace it.
Recoil Starter
The recoil starter assembly consists of several elements that initiate the engine when starting the chainsaw such as the recoil starter pulley and rewind spring. There are several issues that can arise with each of these elements that can prevent your chainsaw from starting.
The rewind spring basically reels in the starter rope once it’s been pulled and released onto the recoil starter pulley. If the rewind spring is not functioning properly, the starter rope cannot recoil onto the pulley, making starting up your chainsaw very difficult or even impossible. You can buy replacement rewind springs for your chainsaw or get a new recoil starter assembly, which may be easier.
Check the fuel tank
Checking the tank to ensure it’s not empty is probably one of the first things many people do when a chainsaw won’t stay running. One factor you probably did not consider as to why your chainsaw won’t start is a result of having bad fuel in the tank. The components of gasoline can evaporate over time, so after storing your saw for several weeks in the garage the chemical breakdown of the fuel in the tank may fail to ignite the chainsaw’s engine.
If this be the case, it is recommended that you drain the tank and use fresh fuel. You should also check the fuel mixture as different engine types use different fuel mixtures. For instance, most two-stroke engines operate using a mixture of oil and gasoline in the tank to provide adequate lubrication. Avoid using boat or automotive oil or any gas mixed with methanol or ethanol as it can damage the engine when it becomes acidic after being left in the tank for a while. There is no one generic ratio for all chainsaws so be sure to refer to the user’s manual on the oil to gas ratio specifications for your model.
A Flooded Engine
In one of the steps to getting your chainsaw started you may have pushed a primer bulb or fuel pump as a means of starting it up easily. Overdoing it, however, could flood the engine and cause it not to start. If you can smell fuel from your chainsaw when trying to start it, this might be an indication that the engine is flooded. Another way you can tell when your engine has too much fuel is by removing the spark plug and checking it for moisture. To solve this problem, open the spark plug hole with it facing away from you to drain all the fuel in the tank. Deactivate the choke by pushing in the control then pull the starter cord 6-8 times as you press in the throttle control. Dry off the spark plug and refit it back in place.
Clogged Carburetor
When you leave fuel in the tank for too long, it will clog the carburetor. As the light elements of the fuel evaporate, the thick substance will remain, which will cause the clogging. The solution is to clean the carburetor carefully using a carburetor cleaner then replace it once the residue has been eradicated. There might be some thick and sticky substances on the chainsaw, so you should clean that as well while you’re at it. Ensure that the carburetor throttle is covered with a tape as you clean the chainsaw. If cleaning it doesn’t seem to help then you might need to consider replacing the entire carburetor.
Dirty Air Filters
Your chainsaw not starting could also be the result of dirty air filters. Clogged and dirty air filters draw more gas than air, similar to when the choke is on. Running a saw with clogged air filters increases the amount of carbon deposits as the engine produces plenty of unburned fuel. Carbon build up can also be contributed by constantly idling the engine. It is recommended that you give your saw a regular hard run, especially for the smaller models. After using your chainsaw for over 5 hours, you should remove the air filter and clean it with soap and water before putting it back.
When Your Chainsaw Won’t Stay Running
Other troubleshooting issues many chainsaw owners can experience is when the chainsaw starts but something goes wrong; it may stall, stop running, chain won’t cut, or the chain won’t stop running. Here are some additional things to check and try if you experience these problems:
Check for Clogged Spark Arrestor
Inside the chainsaw’s engine is a small screen that serves to prevent sparks given off by the engine. This is the spark arrestor and is usually made of fiberglass. It can become clogged from soot over time after many uses which can result in the chainsaw stalling once it starts or to run roughly. This is a simple fix that you can do by simply removing the spark arrestor and using a wire brush to clean it out. If this doesn’t seem to do the trick then you may need to just change it with a new one. The spark arrestor should be replaced after 25 hours of use.
Inspect Clutch Pads for Wear
If the engine starts up but the chain isn’t turning on the chainsaw, it could be the result of worn out clutch pads. When these become worn out from use, they do not engage the clutch drum that enables the chain to turn. Another possible cause for the chain not turning is if the stop lever is not activated. Be sure it is disengaged first to ensure that is not the cause. If it’s the clutch pads that are worn, the clutch assembly will need to be replaced.
Chainsaw Maintenance
Just like any other power tool, a chainsaw is composed of many moving parts within the motor. Most people tend to ignore maintenance and care believing that good quality machines are built to work efficiently. Over time, use of your chainsaw will put wear on the parts that should be checked regularly.
Cleaning and properly maintaining necessary areas can be an effective preventative measure to some of the common problems why a chainsaw won’t start. You will get much longer use out of your power tools if they are taken care of. Here are some tips to keep your chainsaw well maintained:
- Make necessary adjustments to tighten nuts and tension on the chain
- Clean off and remove all necessary parts from debris, sawdust, etc.
- Inspect the sharpness of the chain blade
- Be sure all moving parts such as gears and the chain are adequately lubricated as needed.
Video | Chainsaw Maintenance Tips
Inspect, Clean, and Replace Clogged Filters
There are many different filters within the chainsaw that can get clogged over time and will need to be cleaned or replaced including air filters, the fuel filter, and the foam filter. Any of these becoming clogged can cause starting issues so be sure to inspect all filters and replace as needed.
Fuel Filter -- Fuel that is left in the tank for a period of time can clog the fuel filter as well as the carburetor. You will need to drain the old fuel and replace the fuel filter with a new one. If your chainsaw will be stored for a period of time, draining any old fuel that is left in the tank or adding a fuel stabilizer will help to avoid this.
Chain and Chain Brake Care
To ensure that your chainsaw works efficiently with an extended life, it is very important that you take care of the chain brake as well as the chain. The main maintenance tips for your chain include sharpening, lubricating and adjusting the tension. When working with your saw, it is easy to tell when the chain needs sharpening or when it’s damaged and needs to be replaced. A dull chain will not cut efficiently and can be dangerous.
The chain and chainsaw bar require frequent lubrication to run smoothly and provide efficient cutting as it powers through wood and timber. It is recommended that only environmentally friendly lubricants that contain a non-fling additive is used. The lubricant used with chainsaws must be a specific consistency that is capable of preventing tree sap or debris from sticking, yet still able to cling to the chain. This is why motor oil is not a sufficient source as a chainsaw oil. Poulan and Stihl manufacture their own bar and chain oils specifically formulated for use with their brand chainsaws for optimal performance.
Be sure to refer to the manual that comes with the chainsaw model you have. The manual provides addition information on the various parts that require regular servicing as well as important specifications for the machine’s maintenance.
DIY Safety Tip
When your chainsaw won’t start, there are several troubleshooting and repair steps that you can easily try before seeking the help of a professional. However, you should always practice extra caution while performing any of these troubleshooting steps or maintenance on your machine. Always be sure that you have a firm grip on the handle of your chainsaw, just in case it starts suddenly while checking it.
The most important safety tip when repairing or servicing your chainsaw or any other power equipment is to remove the spark plug and the battery cables to ensure that the engine does not start unexpectedly. You should also wear safety gloves as well as glasses to protect you.