A chainsaw that refuses to start is a common problem. This issue can prevent anyone from cutting wood or performing other tasks that require a functioning chainsaw.
This issue is often called "flooding." It means something prevents the chainsaw from starting right. This happens with gasoline engines or electric motors. You need to understand how to find and fix this problem. This knowledge will help you quickly diagnose and resolve the issue to get your chainsaw running again. It helps you fix the real problem, not just what you see happening. It also gives you insight into how different chainsaws actually work.
1. What Is a Flooded Chainsaw?
"Flooding" most accurately describes a gasoline engine problem. Excess fuel overloads the combustion chamber. However, many people informally use the term 'flooded' to describe any chainsaw that fails to start, regardless of its power source. However, the term 'flooded' is often used informally to describe starting issues, even in electric saws that do not use fuel. In gasoline engines, flooding occurs when the air-fuel mixture becomes too rich due to excessive fuel entering the combustion chamber. The spark plug cannot ignite the fuel correctly. Electric saws seem "flooded" when they fail to start or run poorly. This comes from electrical, mechanical, or battery problems. These issues stop the motor from functioning.
Symptoms of a Flooded Chainsaw
Looking for specific signs tells you what is wrong. Different chainsaw types show different symptoms.
For Gasoline Chainsaws
The engine struggles to start. It takes many pulls of the cord. Still, it does not start. This often points to an issue. You might smell raw gasoline strongly around the chainsaw. This indicates that excess unburned fuel is present, a sign of flooding in the engine. The engine may produce gurgling sounds when you pull the cord, indicating the presence of excess fuel. The engine might start briefly. Then it sputters and dies right away. Or it runs very roughly before stopping unexpectedly. These symptoms suggest the fuel mixture is wrong. The spark plug cannot ignite it well.
For Corded Electric Chainsaws
The chainsaw may exhibit a weak response when you try to start it, such as a low hum or clicking noise. The motor might hum softly. It might click. But the chain does not spin. Sometimes, you get no power at all when you pull the trigger. The motor might run, but slowly. It runs with less power. The chainsaw might feel very hot. You could smell something unusual. It might smell like burning insulation. This indicates an electrical issue, such as wiring problems, or mechanical strain on the motor due to excessive load.
For Cordless Electric Chainsaws
The chainsaw might not power on at all when you push the start button. If it does power on, the motor runs slowly, and it lacks its normal cutting power. If the battery pack feels too warm, it may indicate improper discharge or an internal fault. Similarly to corded chainsaws, the motor can stutter.
It tries to spin but stops suddenly. You might see diagnostic lights flashing. Check the chainsaw body or battery pack for these lights.
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2. Causes of Flooding Chainsaw
Several things cause a chainsaw to fail to start. They also make it run incorrectly. Knowing the cause helps you fix it.
For Gasoline Chainsaws
Over-priming the carburetor is a main cause. The primer bulb sends fuel directly into the carburetor throat, helping cold engines start. Pumping it too many times forces too much liquid fuel into the engine. A faulty or worn carburetor also causes big problems. Parts inside, like the needle valve, control fuel flow. If they fail, too much fuel enters, making the mixture too rich or causing flooding. Incorrect starting procedures, such as improperly using the choke or over-priming, can also lead to too much fuel entering the engine.
Repeatedly pulling the cord with the choke on adds more fuel. Do this after the engine has already sputtered or warmed up. A bad spark plug causes trouble, too. If its tip is covered in wet fuel or oil, it cannot make a strong spark, leaving unburned fuel in the cylinder.
For Corded Electric Chainsaws
Electrical faults stop the chainsaw. These happen in the power cord, internal wires, switch, or motor winding. Electrical faults can prevent current from reaching the motor, often due to issues in the power cord, internal wiring, or connections.
Or they send it the wrong way, which often trips circuit breakers and causes immediate failure. Motor overload happens when you try to cut too much or cut material that is too hard, exceeding the chainsaw's power rating.
A dull chain or wrong tension also makes the motor work too hard, forcing it to draw too much current. Thermal cutouts then activate, protecting the motor from permanent damage. Using the chainsaw wrong, like dropping it, damages internal parts. Wiring gets broken. Poor maintenance lets sawdust build up, blocking vents. The motor overheats, shutting down due to heat. This feels like a starting problem.
For Cordless Electric Chainsaws
Battery problems are a big reason. The battery pack might not hold enough charge. Its internal management system might find a fault. This could be a cell imbalance or getting too hot. It could detect that the battery is too empty and stop the battery from giving power. Electrical faults within the motor controller or motor windings also stop the motor. They prevent it from turning. Overuse also causes issues. Cutting heavily nonstop overworks the motor and battery. A jammed chain also puts a lot of load on them. This triggers the battery system to shut down. It can activate a heat protector in the motor controller, stopping the chainsaw to prevent damage.
The NewBeny 42V 16-Inch Brushless Cordless Chainsaw offers powerful performance with its brushless motor and 42V battery. The 16-inch bar allows longer cuts, making it suitable for larger tasks. It is not easy to flood, showcasing its durable design.
3. How to Recognize if Your Chainsaw Is Flooded
Look for specific signs to confirm the starting problem.
For Gasoline Chainsaws
The engine fails to start after many pulls. Each pull feels spongy or resistant, not like a normal compression stroke. This means liquid fuel is in the cylinder. Another sign is a strong smell of raw gasoline. It hangs around the chainsaw, especially near the muffler. This confirms that the fuel entered the engine but did not burn. Remove the spark plug and inspect the tip for signs of fuel fouling.
If it looks wet, black, and maybe oily, it's fuel-fouled. It's mixed with two-stroke oil, which stops a spark. The engine might briefly fire. It might cough right when you start it. But then it dies. This means it got some fuel and air, but the mix was wrong. Or the spark was too weak. This indicates that while some fuel and air were present, the mixture was incorrect or the spark was too weak to sustain operation.
For Corded Electric Chainsaws
When you try to start it, the motor responds slowly. It might make a low hum or click, but the chain does not spin. This points to an electrical issue, but it might also be mechanical parts stuck. An unusual smell suggests a problem. Burning plastic or ozone smell often comes from the motor housing, which means insulation is breaking down.
The motor windings or control circuits are overheating. Starting attempts result in a weak response, and sometimes, nothing happens at all. First, check the power source. Then suspect a problem inside the chainsaw. It could be electrical parts or the motor itself.
For Cordless Electric Chainsaws
The battery light shows low power, or the chainsaw acts like the battery is dead, even if you charge it. The battery does not deliver enough power. The problem is with the battery pack or its connection. The motor stutters or stops suddenly while you use it. You might hear clicking or grinding sounds. This points to a motor fault. It could be the controller.
Severe mechanical parts could be stuck. An unusual electrical smell or too much heat is a clear sign. It means an electrical problem exists. This often activates a heat shut-off. This protector is in the battery or motor controller. Many cordless saws have lights that flash. They show specific patterns.
These patterns signal different faults. This includes getting too hot, overload, or battery talking errors. Check your chainsaw's manual. It explains what the light codes mean. This gives you specific diagnosis help.
4. Step-by-Step Guide to Starting a Chainsaw
Follow these steps. They are for your specific chainsaw type. They help fix the starting issue.
For Gasoline-Powered Chainsaws
First, turn the engine stop switch to OFF. Then, disconnect the spark plug wire and pull it from the plug end. This prevents accidental starting while you perform maintenance.
Get the right size wrench. Remove the spark plug. Check the tip of the plug. Is it wet or foul?
With the spark plug out, pull the starter cord strongly. Do this about 5 to 10 times. This makes the crankshaft turn, opens the intake and exhaust ports, and pushes extra liquid fuel out of the cylinder. The fuel comes out the spark plug hole. Wipe the old spark plug dry. Use a clean cloth. You can clean it with a wire brush. If it is not too fouled, use contact cleaner.
Inspect the spark plug closely for any signs of damage, such as cracks in the porcelain. Is the electrode worn? Does it have heavy black stuff or oil? If it looks worn or very dirty, put in a new one. Use a plug with the right heat range and gap. Put the spark plug back in by hand first, to avoid screwing it in wrong. Then, tighten it gently with the wrench.
Do not tighten too much. This damages the cylinder head threads. Connect the spark plug wire again. Push it on firmly. Now, set the choke. If the engine was cold when it flooded, open the choke fully. Put it in the RUN position. Some chainsaws have a half-choke setting. Use that if your manual says to after it sputters. Some chainsaws have a "clear flood" way to start. You hold the throttle wide open. Then you pull the cord. This lets in maximum air. It helps clear the cylinder.
Check your chainsaw's manual for this method. Pull the starter cord with force. The engine might need several pulls. It might run roughshod at first. Smoke might come out. This is normal as it burns off the extra fuel. If it still will not start, let the chainsaw rest. Take the spark plug out again. Let it sit for 20-30 minutes. This lets the fuel evaporate from inside the engine. Then repeat the drying and starting steps.
For Corded Electric Chainsaws
Unplug the chainsaw power cord right away. Disconnect it from the wall or extension cord. Look closely at the power cord. Check its whole length. Look for cuts, kinks, or heat marks. Pay attention to where it connects to the chainsaw and the plug. Check if your chainsaw or extension cord has a circuit breaker. It might be a GFCI. See if it tripped. Try to reset it.
Ensure that all safety features, including the chain brake and any safety switches, are properly set according to your manual. This includes the chain brake. Your manual shows the correct starting position. Plug the chainsaw cord back in firmly. Use an outlet that works. Try to start the chainsaw by pulling the trigger. If the motor still does not run, consider overload. The motor might have run poorly before. Make sure the chain brake is off.
Spin the chain wheel by hand. Do this with the chainsaw unplugged. The chain should turn freely. If the chain is stuck in the bar or wood, free it. If the problem continues after checking outside issues, the motor might be broken inside. Windings could be damaged. Brushes might be worn on some motor types. The switch could be bad. A repair person should look at these issues.
For Cordless Electric Chainsaws
Start by taking the battery pack out. Check how much charge it has. Use its indicator lights if they are there. If it is low, try to charge it. See if it charges or shows an error. Look at the battery contacts and the chainsaw's contacts. Clean off dirt or corrosion. Check for damage. Make sure the area where the battery sits has no debris.
Feel the battery and motor area. Are they too hot? This might mean a problem inside, or it could mean a recent overload. If they are hot, let them cool completely. Put the cooled, charged battery back in. Make sure it clicks securely. Some models have electronic controls that you can reset. You might take the battery out and put it back in.
Or press a reset button. Try starting the chainsaw by pulling the trigger. If the motor stutters, makes strange sounds, or stops fast, it could be an overload or a motor or controller problem. Make sure the chain is free and not stuck. If the chainsaw stops while you are cutting, it probably got too hot. The heat protection in the battery or motor controller stopped it. Let it cool longer. If the chainsaw still will not start with a good, charged battery, the battery pack might be bad, and the motor or controller needs repair.
5. How to Prevent Chainsaw Flooding
Using and caring for your chainsaw correctly helps avoid these issues.
For Gasoline-Powered Chainsaws
Always use fresh fuel mixed with oil. Get high-quality oil made for 2-stroke engines. Mix it at the ratio the chainsaw maker recommends. Old fuel can lose its volatility and develop phase separation over time, leading to poor engine performance.
Fuel with ethanol is worse. It harms fuel lines and carburetors and fouls the engine. Use a fuel container with a vent. Do not keep mixed fuel for more than 30-60 days. Learn how to prime your chainsaw. Follow your chainsaw's manual.
Usually, you pump the primer a few times. Stop when fuel shows in the clear return line. Know how to use the choke. A full choke makes the fuel mix rich. Use this for cold starts. Move it to half-choke or run as soon as the engine fires. Or use the run position after a couple of pulls if the engine is warm. Learn the right way to pull the starter cord. Pull it firmly and smoothly. Do it in one movement. This helps the engine build good pressure and draws the right fuel and air mix. Do not use short, jerky pulls. They do not start the chainsaw well and damage the starter. Clean your chainsaw regularly. Keep the air filter clean. Replace it if it is dirty.
Check the spark plug often, cleaning or replacing it. Check the fuel filter, too. It is often in the fuel tank. Make sure fuel lines are not cracked or brittle. Keep your chain sharp. Adjust its tension right. This makes cutting easier and reduces stress on the engine.
For Corded Electric Chainsaws
Use a power outlet and extension cord that handle your chainsaw's power. The cord must be thick enough (the right gauge). This is very important for long cords. It stops voltage from dropping, which prevents motor strain. Do not push the chain saw hard into wood. Let the sharp chain cut itself.
Forcing it makes the motor draw too much power, risking overloading it. Check the power cord and plug often. Look for any signs of damage. Check the chain saw's housing, too. Look for damage. Check the vents on the motor housing. Keep them clear of sawdust. This lets air cool the motor and prevents it from overheating. If the motor feels hot when you use it, stop. Let it cool completely. Then start cutting again.
For Cordless Electric Chainsaws
Start cutting with a fully charged battery. Make sure it sits firmly in the chainsaw. Do not let the battery run completely empty often. Running batteries too low stresses the cells, shortening their life. Do not cut wood that makes the motor struggle. Do not cut wood that makes the chainsaw slow down a lot. This means the load is too high. If the chain gets stuck while cutting, let go of the trigger right away. This stops motor and battery overload. Pay attention to how hot the chainsaw feels. Feel the battery too. If either feels too hot, stop using the chainsaw. Let them cool down fully. Store battery packs as the maker says. Keep them cool and dry. For long storage, keep them partly charged, maybe 50%. Clean battery contacts regularly. Check the motor area on the chainsaw. Remove any debris that stops air flow.
6. Conclusion
Successfully addressing a chainsaw that will not start involves accurately diagnosing the underlying issue. Is there too much fuel in a gasoline chainsaw? Is there a power or motor problem in an electric saw? Follow the steps for your saw type. This often fixes the starting issue. Clean extra fuel. Dry the spark plug. Check electrical plugs. Manage battery charge. Implementing these steps effectively addresses many common starting issues. More importantly, take good care of your chainsaw regularly. Use it only as it was designed. This prevents many problems from starting. Knowing how your chainsaw works helps you keep it running. It also ensures that the chainsaw is ready when you need it.
7. FAQs
When is it not advisable to attempt to start a flooded chainsaw?
Avoid starting if you smell strong gas or the engine feels mechanically locked when pulling. Do not try near sparks or open flames. Forcing a locked engine risks internal damage.
Can flooding cause mechanical damage?
Yes, significant flooding can cause a hydraulic lock. Liquid fuel stops the piston, and forcing it can bend the connecting rod. Repeated attempts also stress and can break the starter system.
What methods help accelerate fuel evaporation after flooding?
Remove the spark plug to vent the cylinder and let fuel drain out. Point the plug hole downwards and allow significant time. Airflow and warmer temperatures aid natural evaporation.
Are drying agents or chemicals effective for clearing fuel floods?
No, do not use drying agents or chemicals; they damage engine components not designed for them. These products are not made for gasoline. Rely on mechanical clearing and natural evaporation instead.
