While performing regular maintenance and using the right fuel through your chainsaw can help minimize problems, you are still likely to encounter issues over the life of your chainsaw.
I’ve put together this guide to help you troubleshoot the cause of your chainsaw problem. Here you will find simple charts with causes and solutions. I’ve also provided links to articles in more detail to further help.
Always follow the safety precautions found in your operator’s manual. Make sure you remove the spark plug wire before beginning repairs.
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Follow all safety instructions provided in your equipment operator’s manual before diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.
Common Chainsaw Problems & Solutions
Problem 1: Chainsaw Won’t Start
Air, fuel, and spark are needed for the chainsaw to start. When you encounter starting problems, look for items that can keep the engine from getting these items.
It is common for old gas to result in a lack of fuel which can result in a starting problem. Make sure you are using the correct fuel mixture for your chainsaw. Consume the fuel within 30 days before it begins to break down.
2-cycle engines require a gas-to-oil fuel mixture. 4-cycle engines require straight gas. Filling the tank with the wrong fuel can cause the chainsaw to stop running. It can also cause significant engine damage.
Detailed information can be found at:
Reasons Your Chainsaw Won’t Start
| Cause | Reason for the Problem | Solution |
| Bad or old fuel | Fuel breaks down over time making the fuel less efficient and prone to clogging the fuel system. | Drain the fuel tank and fill it with fresh fuel. Use a fuel additive like Sea Foam to stabilize the fuel and assist with cleaning the fuel system. 2-cycle and 4-cycle engines have different fuel requirements. Check out this guide to choose the right fuel. |
| Incorrect oil mix for a 2-cycle engine or wrong fuel in a 4-cycle engine. | An incorrect mix can fail to provide the lubrication the engine requires. | Mix gas and 2-cycle oil for 2-cycle engines. Use gas with a minimum 89-octane rating and maximum 10% ethanol content. 4-cycle engines require straight gas. |
| Bad spark plug | A dirty or damaged spark plug; loose spark plug wire, or incorrect gap can prevent the engine from starting. | Replace with a new spark plug, secure connections, and ensure it is gapped to manufacturer specifications. |
| Plugged air filter | Dirt can plug the air filter preventing airflow | Remove the filter and clean it. Replace the filter if it is in bad condition. |
| Plugged fuel filter | A dirty fuel filter will restrict fuel flow. | Replace the fuel filter. |
| Blocked fuel lines | Deposits left behind by old fuel and dirt can clog the fuel lines preventing the engine from getting fuel. | Use a carburetor cleaner and compressed air to clear the clog out of the fuel line. Replace the line if necessary. |
| Plugged fuel tank vent | A plugged fuel tank vent will no longer allow the tank to vent. A vacuum will form keeping fuel from flowing out of the tank. | Replace a plugged fuel tank vent. |
| Plugged spark arrestor | Hot air isn’t able to exit the chainsaw when the spark arrestor is plugged with carbon deposits. | Remove and clean the spark arrestor screen. |
| Dirty carburetor | The carburetor can become dirty and clogged due to bad fuel and ethanol deposits preventing fuel flow. | Clean the components making up the carburetor. Replace it if needed. |
| Bad primer bulb | A cracked primer bulb will fail to move fuel to the carburetor. | Replace the primer bulb |
| Flooded engine | The fuel-to-air mixture is running too rich that it can’t ignite. This can be caused by pressing the primer bulb too many times or pulling the starter rope too many times while the choke is closed. | Remove the spark plug. Place the chainsaw on its side. The spark plug hole should be pointed away from you. Pull the starter 6 to 8 times. Reinstall the clean dry spark plug. Start the chainsaw. |
| Broken starter recoil | A damaged or broken recoil prevents the recoil to start the engine. | Check the recoil to see if it can be restrung. Broken parts must be replaced. Replace the recoil assembly if needed. |
Problem 2: Chainsaw Starts, Stalls & Dies
Many of the items that can cause a chainsaw’s starting problem are also reasons that can cause it to stall and die after running.
Make sure you have adjusted the choke to the open position after the engine has warmed or it will begin to run sluggishly and die due to a lack of air.
If your chainsaw dies after it’s been running awhile and won’t start again until you allow air to enter the fuel tank, you may have a fuel tank vent problem.
Detailed information can be found at:
Your Chainsaw Starts, Stalls and Dies
| Cause | Reason for the Problem | Solution |
| Wrong choke setting | The engine will die when the choke lever isn’t placed in the open position after the engine warms. | Close the choke to restrict air to start a cold engine. Open it once the engine warms. |
| Bad fuel | Fuel breaks down over time making your fuel less efficient and prone to clogging the fuel system and engine damage. | Drain the fuel tank and fill it with fresh fuel. Use a good fuel additive to assist with keeping the fuel stable and cleaning the fuel system. |
| Plugged air filter | Dirt can plug the air filter preventing airflow. | Remove the filter and clean it. Replace the filter if it is in bad condition. |
| Plugged fuel filter | A plugged fuel filter won’t allow sufficient gas to pass through it. | Replace the fuel filter |
| Clogged fuel lines | Bad fuel deposits and dirt can build up and clog the fuel lines preventing the engine from getting the required fuel. | Use a carburetor cleaner and compressed air to clear the clog out of the fuel line. Replace a bad fuel line. |
| Dirty carburetor | The carburetor can become dirty and clogged due to bad fuel and ethanol deposits preventing fuel flow | Clean all the components making up the carburetor. Rebuild or replace if needed. |
| Plugged fuel tank vent | A plugged fuel tank vent will no longer allow the tank to vent. A vacuum will form keeping fuel from flowing out of the tank. | Replace a plugged fuel tank vent. |
| Plugged spark arrestor | The spark arrestor can plug with soot so hot air can no longer exhaust. | Remove the spark arrestor screen and clean it with a metal brush. Replace a damaged screen |
Problem 3: Chainsaw Chain Won’t Turn or Move
The chain may no longer move smoothly around the bar. First thing, never touch the chain without removing the spark plug wire for safety reasons.
Next, look for bar or chain damage or incorrect chain tension. Make sure the bar and chain are sufficiently lubricated, and check for worn clutch pads.
Detailed information can be found at:
Your Chainsaw Chain Won’t Move, Spin or Rotate
| Cause | Reason for the Problem | Solution |
| Chain brake is engaged | The chain brake is a safety guard that reduces the possibility of injury in the event of a kickback by stopping the chain. | Ensure the chain brake is pulled to the rear of the saw so the is not engaged. |
| Bar & chain are not sufficiently lubricated | A buildup of friction and heat due to insufficient lubrication can cause the chain to stop turning on the bar. | Fill the bar and chain oil reservoir. Check the oil channel to make sure there isn’t a clog. |
| Chain tension is too tight | The chain should sit securely around the guide bar and still be able to move easily. The chain should not be hanging loose from the bar. | Remove the spark plug wire. Adjust the chain by loosening the bar retaining nuts. Hold the bar nose up. Turn the tensioning screw counter-clockwise to loosen the chain and clockwise to tighten it. |
| Clutch pads are worn | Worn clutch pads won’t engage the clutch drum to turn the chain. | Replace the clutch assembly. |
Problem 4: Chainsaw Runs With the Choke On
A chainsaw only runs with the choke on when the engine is getting too much air or not enough fuel. The choke is engaged to correct the gas-to-air ratio required so the mixture ignites.
Detailed information can be found at:
Your Chainsaw Only Runs with the Choke On
| Cause | Reason for the Problem | Solution |
|---|---|---|
| Old fuel | Old fuel can leave behind varnish and deposits that cause fuel restrictions and fuel component failures. | Drain the fuel tank and fill it with fresh fuel. Use a fuel additive like Sea Foam to stabilize the fuel and assist with cleaning the fuel system. 2-cycle and 4-cycle engines have different fuel requirements. Check out this guide to choose the right fuel. |
| Fuel line puncture | Air can be sucked into the line increasing the amount of air getting to the engine. | Replace the fuel line. Check for fuel line restrictions. |
| Plugged fuel filter | A dirty plugged air filter restricts airflow. | Replace the air filter. |
| Bad carburetor gasket | The gasket may no longer seal allowing excess air into the carburetor. | Remove the carburetor and replace the gasket. |
| Dirty carburetor | Fuel passages can clog and no longer allow sufficient gas for the combustion process. | Remove and clean the carburetor. Rebuild or replace it if needed. |
| Plugged fuel tank vent | A plugged fuel tank vent will cause a vacuum to form in the fuel tank. This will keep fuel from flowing out of the tank. | Replace the fuel tank vent. |
Problem 5: Chainsaw Loses Power and Bogs Down
It is often a dirty carburetor that causes a chainsaw to lose power and bog down. Old gas clogs the fuel passageway.
Check for items that interfere with the air and fuel mix. You should also check the exhaust to make sure hot air is able to exit from the chainsaw.
Detailed information can be found at:
Reasons Chainsaw Loses Power & Bogs Down
| Cause | Reason for the Problem | Solution |
|---|---|---|
| Old fuel | Old fuel can leave behind varnish and deposits that cause fuel restrictions and fuel component failures. | Drain the fuel tank and fill it with fresh fuel. Use a fuel additive like Sea Foam to stabilize the fuel and assist with cleaning the fuel system. 2-cycle and 4-cycle engines have different fuel requirements. Check out this guide to choose the right fuel. |
| Plugged air filter | Good airflow cannot pass through a plugged air filter. | Replace the air filter. |
| Dirty spark plug | A dirty spark plug can cause an intermittent spark. | Clean or replace the spark plug. |
| Plugged fuel filter | Sufficient fuel is unable to pass through a plugged filter. | Replace the fuel filter. |
| Clogged or punctured fuel line | Clogged fuel lines can keep fuel from getting to the carburetor. | Try to clean the fuel line or replace it. |
| Plugged fuel tank vent | A plugged fuel tank vent will cause a vacuum to form in the fuel tank. This will keep fuel from flowing out of the tank. | Replace the fuel tank. |
| Plugged spark arrestor | The spark arrestor can plug with soot so hot air can no longer exhaust. | Remove the spark arrestor screen and clean it with a wire brush. |
| Chain brake is engaged | The chain brake is a safety device to stop the chain in the event of a kickback. | Place the chain brake in the off position. |
| Dirty carburetor | Fuel passages can clog and no longer allow sufficient gas for the combustion process. | Clean the carburetor to remove varnish left behind by old fuel. Rebuild or replace it if necessary. |
| Carburetor requires an adjustment | The RPMs at idle speed and full throttle may need to be adjusted for good performance. | Refer to your operator’s manual to properly adjust your chainsaw’s carburetor. |
6. Chainsaw Is Smoking
When your chainsaw smokes when cutting, you need to look for items that can cause increased friction between the bar and chain.
You may experience smoke coming from the engine and exhaust. This may be due to a wrong fuel mixture, water in the fuel, or a plugged air filter.
Detailed information can be found at:
Reasons a Troy-Bilt Chainsaw Smokes
| Cause | Reasons for the Problem | Solution |
|---|---|---|
| Dull chain | More pressure must be applied when using a dull or incorrectly sharpened chain. Pressure increases friction. | Sharpen a dull chain. Have the chain professionally sharpened if you are unsure how to sharpen the chain for safe use. |
| Tight chain | Friction and smoke occur when the chain isn’t able to move freely around the bar. | Remove the spark plug wire and adjust the chain. |
| Empty bar & chain oil tank | Friction builds when there is a lack of oil. | Fill the tank with bar & chain oil. |
| Wrong bar & chain oil | Too thin of oil will not sufficiently stick to the bar. | Use a good oil like Husqvarna or ECHO Bar & Chain Oil. |
| Clogged oiler | Oil isn’t able to lubricate the bar and chain when the oiler is clogged. | Clean the oiler. |
| Plugged air filter | A plugged filter will cause the fuel mixture to run rich resulting in smoke. | Replace a very dirty air filter. Check and clean it regularly. |
| Too much oil in the fuel mixture | More oil than required in Troy-Bilt 40:1 fuel mix can cause the chainsaw to smoke. | Drain the fuel and fill the tank with the correct fuel mix. |
| Water in the fuel mixture | Water can create white exhaust smoke. | Drain the fuel and fill the tank with fresh fuel. |
Don’t Skip Your Chainsaw Maintenance
Like other outdoor equipment you own, you will eventually experience a problem with your chainsaw.
Regularly maintaining your saw and always running fresh fuel through it will help reduce problems developing in the saw and increase its life expectancy.
I recommend completing a full maintenance service on your chainsaw once a year to keep it in good condition.
The annual service includes replacing the maintenance parts: air filter, fuel filter, and spark plug. You should also check the fuel system and cooling system, and clean the exterior.
Tighten any loose hardware and replace any damaged or missing parts. In addition, you must inspect the chain before each use to ensure it is in good condition.