How to Fix a Chainsaw That Won’t Start

fixing-chainsaw It’s a beautiful day outside and you’re looking for something to do. You’ve been wanting to cut down some trees in your yard but can’t figure out how because all your chainsaw won’t start.

In this blog post, I’ll go through the steps of troubleshooting a chainsaw that won’t start, from checking the gas tank to replacing the spark plug and more. Let’s get started!

Common Reasons Why Chainsaw Won’t Start and How to Fix Them

Reason 1: Fuel

The most common reason for a chainsaw not starting is a lack of fuel or air in the carburetor. The first step is to remove the spark plug and take it out of the chainsaw and dip it into some petrol. If you see a strong spray of fuel, this shows that there’s no blockage in the line between the tank and engine – so next check that there’s actually enough petrol in your chainsaw to run properly. Ensure that you replace your chain cover as well as check for any damage such as cracks before proceeding with other checks.

If you don’t see much spray, then usually check whether or not there is sufficient ventilation around your chainsaw – if not,  there is a chance that the petrol may have evaporated inside the fuel tank.

If this is the case, you’ll need to unscrew your chainsaw’s fuel cap and let out all of the remaining vapors, then mix in some fresh petrol before trying again.

If you still don’t see any spray at all, then there could be a blockage further up – usually caused by old petrol or dirt. It needs to be very fine gasoline or else it will clog up your line into the carburetor, so if possible try cleaning it with paper towels first. If that doesn’t work, use a thin wire inserted down through the jets (underneath where the spark plug goes) until it is down to where everything comes together – where you should be able to push out any clogs with ease. If that still doesn’t work, then the last resort is to remove the carburetor itself, soaking it in gasoline overnight or until you are confident that all petrol has been removed.

Still no pressure? Then your fuel tank might have sprung a leak…or there’s a problem with your pump. Sometimes if there’s dirt in the fuel tank blocking the pick-up tube, water seeps in and rusts out everything inside. You’ll need to drain everything out of your chainsaw’s fuel tank (including old gasoline) and check for blockages on your underside pickup tube (underneath where your fuel line is connected). Replacing this would be fine if you’ve had it for a while. If you are concerned, try blowing through the tube after removing the fuel line. If this is blocked, clean out with wire brush and some high-pressure water or suck up some petrol into it to clear it out first.

Reason 2:  Faulty Fuel Filter

When your fuel filter gets clogged up to the point that it can’t do its job, sand and other debris in gasoline will cause problems. If the sand is blocking enough so that fuel can’t get through, this will hurt your saw. Likely solution: Unfortunately you need to replace your gas tank’s entire fuel filtration system. Not cheap but necessary if you don’t want to take chances or pay for repairs later on when sand clogs up something expensive in your chainsaw.

Reason 3: Your Carburetor Needs Cleaning or Adjustment

A dirty carburetor won’t let air flow at a fast enough rate, which means it can’t burn gasoline efficiently. The end result is that your saw spits, pings, and dies. Cleaning the carburetor or having it adjusted by a professional can solve this problem.

Reason 4: Your Air Filter Is Dirty (or Missing)

A dirty air filter can choke your saw by slowing down the gas flow. Don’t try to clean your air filter, just replace it.

Reason 5: The Air Filter Is the Wrong Size

No matter what you do or how well you maintain your chainsaw, if the carburetor intake/air filter intake is set up for a 50cc engine and your saw has an 80cc engine, you’re asking for trouble. Get rid of that mismatch!

Reason 6: Your Spark Plug’s Gapped Incorrectly Or Has Gone Bad

If the gap between electrodes on your spark plug is too big or too small, the plug won’t fire properly. If it’s getting weak, the plug will misfire and burn up. As a result, you’re not getting good compression and your saw isn’t running smoothly: reason enough to replace that plug!

Reason 7: The Saw Is Uncharged

If your chainsaw is cordless, low voltage might cause it to act flaky. Not only will this make your saw hard to start, but the batteries also won’t last long so you’ll probably be recharging them all the time which is no fun either! On the other hand, if your power cord appears damaged or worn you could have a problem charging your battery.

Reason 8: The Saw Is Overheated

Turn off the saw immediately if it starts to overheat! It takes a while for a chainsaw engine to cool down, so make sure you give it plenty of time before trying to restart it.

Reason 9: The Saw Is Dirty

If your chainsaw is dirty or contains dirt, dust or other impurities, it can create problems with starting.

Reason 10:  The Saw Is Not Getting Enough Oil

If you don’t add enough oil to your chainsaw, the engine is going to be overheated when it is used for a long time and will stop starting eventually. The manufacturer’s guide will tell you how much bar and chain oil your machine needs in order to function properly.


Now that you know how to fix a chainsaw, don’t let your tool get the best of you. Don’t be like some other people and wait until it’s too late! Start reading this blog post now, so next time you can quickly make minor adjustments before calling in for help or heading out to purchase a new one. I hope I’ve helped solve the mystery behind why your chainsaw isn’t starting and given you some tips on how to maintain it better going forward. If not, please reach back out and I’ll try my best to point you in the right direction.

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