A chainsaw that won’t start can be frustrating. Pulling the cord of a saw over and over can be tiring. If something is wrong with your saw, no amount of pulling is going to start it. Below are ten reasons your saw may not be starting. At the end of the article, I’ve provided some general tips to prevent many of the problems listed.
Saw Has No Fuel
It may seem obvious, but one common reason why a chainsaw won’t start is that it has no fuel. Getting caught up in the job can cause people to overlook the essential things.
Chainsaws need a mix of gasoline and 2-stroke engine oil. The ratio of gas to oil is 50:1. This ratio means you will need 2.6 fl oz of oil for every one gallon of gas.
Having no fuel is a simple fix. Fill up your saw with gasoline, and also check to see if your saw needs bar oil too. Once filled, your saw should start without any issues.
Again, the on/off switch being in the right position might seem obvious. I’ve seen this before, and admittedly I’ve fallen for it too.
Some on/off switches can be a little confusing. Generally, the switch needs to be down, activating the choke. Using the choke on a saw increases fuel flow into the engine and decreases the airflow. Starting a saw with the choke needs to be done when the saw is cold. Keep trying to start the saw in a choke position until the engine begins to turn over.
When the engine has started turning over, change the on/off switch to the warm start position. Now keep trying to start the engine until it is on and stays running.
Chainsaw fuel doesn’t last too long. If you don’t use your chainsaw frequently, the fuel left sitting in your saw can go off. It only takes about a month for the fuel to start going bad.
The gasoline that has gone bad becomes sticky; this happens when the liquid part of the fuel starts to evaporate.
To prevent the fuel from going off, it’s a good idea to empty the fuel tank after use. Draining the fuel tank isn’t something I need to worry about as I use my saws every day. If you use your saw every few weeks or even months, empty your saw once finished.
If you suspect your gasoline has gone off, you will need to drain the tank. Once depleted, the tank will need a good clean. To clean the tank, you will need to disconnect the fuel line. Next, you will have to fill the gas tank with a commercial cleaner. Each cleaner will have its own set of instructions to follow. Generally, after you fill the tank with cleaner, you will put the lid back on and shake the saw.
After you finish cleaning your fuel tank, put in some fresh fuel, and now your saw should start.
Chainsaw Has Flooded
A flooded chainsaw is when too much fuel has been pumped into the engine. If there is too much fuel in the machine, it means there isn’t enough oxygen; this will prevent your saw from starting.
There are a few reasons why a saw may flood:
- Poor fuel quality
- Saw not cranked properly
- Cold temperature
Poor fuel quality
As mentioned above, low fuel quality is a problem for saws. If you attempt to start your saw with off fuel, the saw can flood. If you don’t realize the gas is bad, repeatedly starting the saw will flood the engine. Again, to prevent off fuel, drain your tank after use.
Saw not cranked properly
If a chainsaw is over-cranked, it can flood. Over-cranking happens when starting the saw has been attempted too many times without success.
The choke position on a saw allows a richer fuel mix into the engine. Having the saw in the choke position and attempting to start it for too long can cause too much fuel in the machine.
If your saw is flooding from too many attempts, give your saw a break. If your saw always has difficulty starting, there may be another issue. Servicing or identifying the problem can prevent the chances of flooding in the future.
When the temperature is cold, chainsaws can take a little longer to start. If someone isn’t aware of this, they try too hard to start the saw. Too many unsuccessful attempts at starting a saw will lead to flooding.
To prevent saw flooding from a cold start, try a few times, then take a break. Eventually, the saw will start.
If your saw has flooded, the easiest fix is to wait. Switch the saw to the off position and give the saw a few minutes. The oxygen levels in the engine need time to rise again. After a few minutes have passed, the saw will be ready to start.
Bad Spark Plug
For a saw to start, the spark plug needs to ignite the fuel. The ignition creates a small explosion, giving the saw power. If there is an issue with the spark plug, the saw won’t be able to ignite.
- Wet spark plug: If a spark plug is wet, it won’t produce the spark needed to ignite the fuel. The most common way a spark plug becomes wet is by engine flooding. To fix a damp spark plug, you can wait for it to dry itself. A quicker method is to remove the spark plug and dry it with a clean rag.
- Old and worn spark plug: Over time, a spark plug will naturally degrade. Signs of degradation can be cracks in the porcelain, a burned-out electrode, or dirt build-up. In most cases, replacing the spark plug is a quick and inexpensive fix. It is possible to clean dirty spark plugs, but replace your spark plug if it is damaged.
Air Filter Blocked
The air filter in a chainsaw prevents dust and dirt from entering the engine. Over time, the air filter can become blocked by too much dust. If the air filter is clogged, the air isn’t getting into the engine.
Part of regular chainsaw maintenance is the checking of the air filter. Checking the air filter is easy to do, and if done regularly, it shouldn’t be hard to clean. Giving the air filter a few taps on a bench or a gentle blow with an airgun will remove any debris.
Damaged or air filters that are too dirty will need replacing. Air filters are cheap and can be purchased online.
A carburetor on a chainsaw is responsible for maintaining the correct fuel and air mix. The carburetor monitors small amounts of fuel and mixes it with the air that enters the engine.
If the carburetor is clogged, it won’t be able to mix the fuel and air correctly. A saw won’t start with a clogged carburetor.
If the carburetor is slightly dirty, you can get away with a quick clean. However, if the carburetor is majorly dirty, you will need to either replace or rebuild it. New carburetors aren’t too expensive, but it can get complicated trying to replace them.
Cleaning the carburetor is a long process and can get complicated if you are a beginner. There are many components to a carburetor; taking them all apart and cleaning each piece can take some time. You will need to ensure each part is installed correctly before starting your saw.
Blocked Spark Arrestor
The spark arrestor on a saw is there to prevent sparks from flying out of the saw. If these sparks got out, they could start fires.
When spark arrestors get dirty and clogged, they can also prevent your saw from starting. Spark arrestors are part of the saw’s exhaust system. A clogged spark arrestor will stop air from leaving the motor. If burned air can’t escape the engine, the oxygen levels will be off, causing the saw to stop working. Your saw won’t be able to start if the exhaust can’t leave the engine.
The best fix for a clogged spark arrestor is to clean it out. To find the spark arrestor on your saw, refer to your user manual. In most instances, the spark arrestor will be near the muffler. Unscrew the muffler cover to access the spark arrestor. To remove any build-up, use a blow torch. Burning off any dirt is the easiest way to clean a spark arrestor, a lighter works just as well as a blowtorch.
Blocked Fuel Filter
The fuel filter is responsible for keeping dirt and other particles out of the fuel. If too much grime builds up on the fuel filter, it will prevent fuel from entering the engine. Thus, the saw won’t start.
Fuel filters are very cheap, so it’s easier to replace them as needed. As air and fuel filters are so inexpensive, it’s worthwhile investing in a few of each. If you have spare parts lying around, you won’t be stuck waiting around if your saw needs fixing.
Recoil Pull Starter
The recoil pull starter is the unit responsible for starting a chainsaw. You can find the pull cord in this part of the saw. When the operator pulls the rope, the rope spins the crankshaft. The crankshafts spinning will engage the flywheel, allowing the engine to start. If you have a problem with this unit, you won’t be able to start your saw.
One of the most significant issues the recoil pull started can have is the cord not rewinding. The pull cord has a rewind spring; this spring will rewind the cord up after it is out. Without the rewind spring working effectively, the rope will not rewind. Thus the cord won’t be able to be used.
Some chainsaw brands will allow you to replace the rewind spring. Others will force you to replace the whole assembly unit. One brand that does let you replace the spring is Echo.
Changing the spring should only take about 15 minutes. The saw needs to be off with the spark plug disconnected. Next, the starter assembly unit will need to be opened. Once inside, take each piece out until the recoil spring is visible. Take the spring out and replace it with the new one. Be careful doing this as the spring is sharp. Once the new spring is in, put the saw back together and reconnect the spark plug. The saw should start now.
Replacing the whole unit will be similar; rather than taking apart the unit to get to the spring, the entire unit will come off in one. Switch the unit out and replace it with the new one.
There are many reasons a saw may not start. It’s easy to avoid most of these problems with proper saw maintenance.
Start by running your saw frequently. If you don’t use your saw often, it’s a good idea to start up the saw once a week and let it run for a bit; this will keep all parts active and running.
After you finish using your saw, please give it a good clean and chain sharpening. As I use my saws every day, I do this as part of my morning routine.
Always use fresh fuel when using your saw. If you don’t use your saw often, drain the fuel after use; this will prevent the fuel from going bad.
Get your saw serviced as per the manufacturer’s recommendations. Having your saw serviced will go a long way in preventing issues and improving the saw’s longevity.
My name is Matt. As a profession, I specialise in Arboriculture for more than seven years. Here I share my views on trees to help beginners and experts with pruning, planting, cultivation of trees, shrubs, and woody plants and their health assessments.