Chainsaws are invaluable tools for felling trees, pruning branches and cutting up firewood. Yet like all power tools, they can sometimes be a little stubborn starting up.
With gas-powered chainsaws, there are quite a few things that can go wrong, but fortunately, most of them are relatively easy to fix. Here, we look at the top 11 reasons why your chainsaw won’t start.
If you want a preview of some of the things we’ll be looking at, you can check out this video before reading on.
How to check for possible problems
Whenever any kind of machinery breaks down, the correct way to diagnose the problem is to start with the most basic issues and eliminate each possibility one by one until you find what’s wrong. Here’s what you need to check with a chainsaw.
1. Check it has fuel!
Let’s get this out of the way first. Does your chainsaw have gas in it? Yes? Ok, good. Onto the next one.
2. Check it has fresh fuel
Does your chainsaw have fresh fuel in it? Gasoline doesn’t last long, and if it has been sitting inside your chainsaw for anything over about a month, it will start to deteriorate. After this, part of the liquid content will begin to evaporate, leaving a sticky goo.
If your chainsaw has old fuel inside, you need to remove it. Clean the inside of the tank, add fresh gas and try again.
3. Is the carburetor clogged?
A slightly more serious consequence of leaving old fuel in the engine for too long is that the carburetor can become clogged as the fuel turns sticky – which will definitely prevent you from starting the engine.
If it’s not too bad, you might get away with cleaning the carburetor. Otherwise, you may need to rebuild or replace it entirely.
4. Check the spark plug
Another common reason a chainsaw won’t start is that the sparkplug is old, dirty, damaged or not correctly attached.
Check to make sure the porcelain insulator is not cracked and that the electrode has not been burned away. Also, look to see if there is excessive carbon build-up
If it’s only a little dirty, give it a clean – but often, since sparkplugs aren’t expensive, it’s easier just to replace it anyway.
5. Check the engine isn’t flooded
If you pressed the primer bulb too many times, you may have flooded the engine – a good indication of this will be if you can smell gasoline.
If you think you have a flooded engine, drain the fuel, push the choke back in and pull the starter cord about eight times while holding the throttle. Dry and replace the spark plug and start again.
6. Check the air filters
If the air filter is clogged or dirty, this will affect the air-to-gas ratio and may prevent the engine from firing up. If it won’t start, check the air filter and clean as necessary.
As part of your general chainsaw maintenance, you should regularly clean your air filter – and if it becomes excessively dirty, you should replace it completely.
7. Is it too cold?
If the temperature is too low, it can make it hard to start a chainsaw. If you live somewhere cold and you’re having trouble starting your chainsaw, try giving it a little more choke. This should help in most cases.
8. Ignition coil
If you’ve checked everything above and still haven’t found the cause, the next possibility to consider is the ignition coil.
This is what sends voltage to the sparkplug, causing it to spark, and if this isn’t happening, your chainsaw won’t be able to function.
To check if the ignition coil is to blame, you need to use an ignition coil tester or a multimeter. If you discover this is the reason your chainsaw won’t start, your only option is to replace the ignition coil
9. Rewind spring
Another common problem has to do with the rewind spring. This is the spring that rewinds the starter cord after each pull, and if it is broken, the cord won’t wind up again – meaning you won’t be able to start your chainsaw.
If the starter cord doesn’t wind back in after you pull it, you might be able to just replace the spring, depending on the model of your chainsaw. However, with many models, you may have to replace the whole recoil starter assembly.
10. Recoil starter assembly
If your recoil starter has a problem, pulling the starter cord won’t cause the engine to turn over and so it won’t fire up. If none of the above reasons appears to be the problem, this is the next thing to check.
To check, you will need to remove the whole recoil starter assembly. Pulling the cord should cause tabs to extend from the pulley and cam, grabbing the hub on the engine and making it turn over. The tabs then retract and the cord is pulled back in when you release the cord.
If this isn’t happening correctly, the recoil starter assembly is defective, and you need to replace it.
11. Blocked or clogged spark arrestor
The spark arrestor is a screen that prevents sparks from flying out of the chainsaw while it is being used and that also affects the fuel-air mixture.
With time and use, this can become blocked and needs to be cleaned regularly. If your chainsaw won’t start, it is worth checking the state of the spark arrestor to see if it requires cleaning.
Electric and battery-powered chainsaws
If you are having trouble starting one of these machines, the only advice is to check all the most obvious possible issues.
With corded chainsaws, check it is plugged into an outlet and that the power is on. With battery-powered models, make sure that the battery is fully charged.
Beyond simple checks like this, if one of these types of chainsaw doesn’t start, you might need to have it looked at by a professional.
Check methodically to identify the problem
By working through all the possible problems in a methodical way, you can diagnose the issue. Once you know what is wrong with your chainsaw, you can then take the necessary steps to fix it.
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