Chain Saw: Starts But Immediately Dies

The carburetor is a part that, when plugged or improperly adjusted, can cause your chainsaw to start up, but immediately die. Many carburetors have adjustment screws, and you may be able to use them to get your engine working properly again. If you’ve worked to adjust to the carburetor and it’s still causing this problem, it is probably plugged. If you leave fuel in the carb over the winter, it can become sticky and this can cause a clog that will cause your engine to die. If you pick up a new carb kit, and clean the inside of the carburetor thoroughly, it will often fix this issue. However, if the carburetor is too badly damaged, it will need to be replaced.

A clog in the air filter can starve the engine of fuel and cause it to die. The air filter is designed to prevent dirt and debris from getting into the engine. This debris can build up and create a clog, which will prevent air from reaching the engine. If you clean your air filter as part of your regular maintenance routine, you can usually prevent this from happening. Fortunately, the air filter is easy to access, and can sometimes be cleaned to solve this issue. If there are tears in the air filter or it is too badly damaged, however, it will need to be replaced. This part is inexpensive and replacement is recommended if there’s anything lasting wrong with it.

The fuel filter in your chainsaw is found at the end of the fuel lines, inside the fuel tank. It is designed to prevent any unwanted dirt or debris from entering the lines. If the fuel filter is damaged, this debris can enter the lines causing a clog, and preventing your chainsaw from running. The fuel filter can also become clogged, and this will prevent fuel from reaching the engine, causing it to die. Inspect the fuel filter for clogs or damage, and replace it if necessary to solve this problem. You may need a hook to remove the fuel filter from the fuel tank. Replacing this part should be part of regular chainsaw maintenance, as it’s inexpensive and essential.

A fouled spark plug can cause your chainsaw to start but immediately die. A spark plug is considered fouled when the insulator nose at the firing tip becomes coated with a foreign substance such as fuel, oil, or carbon. This coating makes it easier for the voltage to follow along the insulator nose, leach back down into the metal shell and ground out rather than bridging the gap and firing normally. An incorrectly adjusted carburetor can result in a rich fuel mixture, and this can lead to spark plug fouling. Once the spark plug is fouled, we recommend that you replace it, and your problem should be solved as a result.

Picking up a carb kit and cleaning the inside of the carburetor is a great way to ensure the carb is functioning properly. Often, a gummed-up carburetor is causing this symptom, so if the small parts inside are replaced and it is cleaned, fuel will be able to flow again, and your chainsaw will run properly. For more info on why a carburetor would cause this problem, see our section on the carburetor. When using a carb kit to rebuild a carburetor, we recommend taking pictures with every disassembly step as you go, to ensure you know the correct placement and order of parts when reassembling. This is especially important if it is your first carburetor teardown.

Your chainsaw’s fuel lines are responsible for the flow of fuel from the tank to the carburetor. A cracked fuel line can cause fuel to leak out, and this will prevent it from entering the engine. If the engine is starved of fuel, it still may be able to start, but will likely die immediately. Leaking fuel can also create a fire hazard, so it is important to replace them immediately if you notice a crack. A quick visual inspection of the lines should be all that is required to determine if the lines are cracked. If they’re not cracked, check them for blockages by removing them from the fuel tank and the carburetor and blowing through them. To replace, simply disconnect the lines from the fuel filter and the carburetor, and replace with new line.