Keeping your STIHL leaf blower well-maintained by performing routine service and using fresh fuel will help minimize the issues from developing. It also helps you catch small problems before the become large problems.
However, when you own a leaf blower long enough, chances are you’ll run into some problems with the engine and fuel system.
To help you identify common STIHL leaf blower problems so you can perform troubleshooting procedures, I have put together tables with links providing information in more detail.
Always follow the safety procedures found in your STIHL operator’s manual. This includes waiting for the engine to cool and for all parts to stop moving. Remove the spark plug boot prior to performing repairs.
Common STIHL Leaf Blower Problems:
- Leaf blower won’t start
- Leaf blower starts then dies
- Leaf blower runs rough and sputters
- Leaf blower only runs with the choke on
- Leaf blower loses power and bogs down
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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 STIHL Leaf Blower Problems & Solutions
1. Blower Won’t Start
To troubleshoot a starting problem, look at the items that keep air, fuel, and spark required to start the blower.
Check the fuel. Using straight fuel or fuel without enough lubrication can keep the engine from starting. Avoid fuel restrictions due to old fuel by choosing the right type of fuel and using it within 30 days.
Choose an unleaded gas that has a minimum 89-octane rating (mid-grade) and a maximum ethanol content of 10%. Stay away from gas with higher ethanol contents than this.
Mix with a premium 2-cycle engine oil like STIHL High Performance or STIHL HP Ultra. Use a fuel stabilizer to keep the fuel stable and reduce moisture in the fuel system.
Detailed information can be found at:
Reasons Your STIHL Leaf Blower 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 gas and 2-cycle oil. mix at a ratio of 50:1. Use a fuel additive like Sea Foam to stabilize the fuel and assist with cleaning the fuel system. Use the right fuel. |
| Incorrect 2-cycle oil mix | An incorrect mix can fail to provide the lubrication the engine requires. | Mix gas and 2-cycle oil at a rate of 50:1. Use gas with a minimum 89-octane rating and maximum 10% ethanol content. |
| 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 to flow out of the tank. | Replace a plugged fuel tank vent. |
| Plugged spark arrestor | Hot air isn’t able to exit the leaf blower when the spark arrestor is plugged with soot. | 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. | Turn the switch to the run position. Move the choke lever to the run position. Press the throttle trigger while pulling the starter rope over and over. |
| Broken starter recoil | A damaged or broken recoil prevents the recoil from starting your engine. | Check the recoil to see if it can be restrung. Broken parts must be replaced. Replace the recoil assembly if needed. |
2. Blower Starts Then Dies
Many of the items that prevent a STIHL leaf blower from starting are also the same items that can cause it to stall and die after it’s been running.
If the blower starts and dies soon after, ensure you are starting it correctly. The choke lever must be placed in the on position to restrict airflow to start a cold engine.
Once the engine warms, it must be placed in the off position or the engine will no longer run.
Detailed information can be found at:
Your STIHL Leaf Blower 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 and 2-cycle engine oil mixed at a ratio of 50:1. Use a fuel additive like Sea Foam to stabilize the fuel and assist with 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 carb cleaner and compressed air to clear the clog out of the 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 to flow 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 |
3. Blower Runs Rough and Sputters
A dirty carburetor is often the reason your STIHL blower begins to run rough and sputter. This is common when old gas clogs the fuel passageways so the engine isn’t getting sufficient fuel.
Another common item that can cause this is a plugged spark arrestor that won’t allow hot exhaust air to leave the engine.
Detailed information can be found at:
Your STIHL Leaf Blower Runs Rough
| Cause | Reason for the Problem | Solution |
| Old fuel | Old fuel leaves behind gummy deposits that can restrict fuel and cause component failure. | Remove old fuel and replace it with fresh gas and 2-cycle engine oil mix at a ratio of 50:1. Add a fuel additive like Sea Foam Motor Treatment to stabilize gas and clean the fuel system. |
| Dirty spark plug | The intermittent spark from a dirty spark plug can cause it to run sluggishly. | Replace the spark plug. |
| Plugged fuel filter | A good flow of fuel is not able to pass through a plugged fuel filter. | Replace the fuel filter. |
| Clog fuel lines | Fuel is restricted when the fuel line develops a clog due to old fuel or dirt. | Clean or replace the fuel line. |
| Plugged fuel tank vent | When the fuel tank is unable to vent, it forms a vacuum that keeps fuel from leaving the tank. | Replace the fuel tank vent. |
| Plugged air filter | The air filter can become plugged with so much dirt that sufficient air isn’t able to pass through it. | Replace the air filter. |
| Dirty carburetor | Fuel passageways in the carburetor become plugged with old gas deposits keeping sufficient fuel from getting to the engine. | Remove the carburetor and clean it. Rebuild or replace it if needed. |
| Plugged spark arrestor | Hot exhaust air isn’t able to exit the blower when the spark arrestor is plugged with carbon buildup. | Remove and clean the spark arrestor screen. |
4. Blower Runs With the Choke On
The choke is used to restrict airflow. Your choke may need to be used once the engine is warm to correct the fuel and air mixture to keep the blower running.
This is usually due to the engine receiving too much air or not enough fuel. Look for fuel restrictions and places where additional air can get drawn into the cylinder.
Detailed information can be found at:
Your STIHL Leaf Blower 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. Refill with fresh gas and 2-cycle oil mixed at a ratio of 50:1. Use a fuel additive to stabilize fuel and clean the fuel system. Start and allow the fuel to work its way through the fuel system. |
| 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. |
5. Blower Loses Power and Bogs Down
When a STIHL blower isn’t giving you good power or is bogging down, the cause is often a dirty carburetor and other items that are restricting fuel.
Other items to check are those that keep hot air from exiting the blower, air from getting to the engine, or spark problems.
Detailed information can be found at:
Reasons STIHL Leaf Blower 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. Refill with fresh gas and 2-cycle oil mixed at a ratio of 50:1. Use a fuel additive to stabilize fuel and clean the fuel system. Start and allow the fuel to work its way through the fuel system. |
| 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 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. |
| Carbon buildup on the exhaust port | Carbon that builds up in the exhaust port and hot air isn’t able to exit through the muffler. | Clean the exhaust port. |
| 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. |
Don’t Skip Maintenance on Your STIHL Leaf Blower
While you will experience a problem with your STIHL blower at some time, you can minimize significant problems by performing regular routine service.
I recommend completing a full maintenance service on your STIHL blower 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 to this, you must inspect the blower before use to make sure it is in good condition before operating.