As a professional lawn care team, we rely on our tools to get the job done efficiently and effectively. That’s why we trust in our Stihl string trimmers to keep our clients’ lawns and gardens looking their best.
However, just like any tool, our Stihl string trimmers can encounter issues that prevent them from starting. Here are some common reasons why your Stihl string trimmer may not start and how to solve them:
Plugged Air Filter: Like any engine, a Stihl string trimmer’s air filter protects it from dirt and other contaminants. A dirty or plugged air filter can prevent air from passing through and reaching the engine, causing it to fail to start.
Like with Ryobi string trimmers, a Stihl string trimmer may also fail to start or run sluggishly due to a plugged air filter. The air filter is responsible for keeping dirt and debris out of the engine, preventing damage and prolonging the life of the trimmer.
A plugged air filter on a Stihl string trimmer will restrict the flow of air into the engine, which can cause starting and performance issues. Over time, dirt and debris will build up on the filter, preventing it from properly filtering the air.
It’s important to check and clean or replace the air filter regularly to ensure that the engine is getting enough air to run properly. Stihl recommends cleaning the air filter after every 5 hours of operation or at least once a month, and replacing it every 50 hours of operation or once a year, whichever comes first.
To clean the air filter on a Stihl string trimmer, remove the cover and take out the filter. Clean it with a soft brush or compressed air, making sure to remove all dirt and debris. If the filter is damaged or excessively dirty, it should be replaced with a new one.
It’s important to never operate a Stihl string trimmer without an air filter, as this can cause serious damage to the engine. Always replace the air filter with a new one if it is damaged or excessively dirty.
Solution: Remove the air filter and clean or replace it as needed.
Bad Spark Plug: The spark plug is responsible for igniting the fuel in the engine. Over time, the spark plug can become dirty or worn, causing it to misfire or prevent the engine from starting.
A bad spark plug is a common problem that can prevent your Stihl string trimmer from starting. The spark plug is responsible for igniting the fuel in the combustion chamber, which is necessary for the engine to start and run. If the spark plug is not functioning properly, the engine will not start or will run poorly.
There are several signs that indicate a bad spark plug in your Stihl string trimmer. These include difficulty starting the engine, rough idling, reduced power, and increased fuel consumption. If you notice any of these symptoms, it is important to inspect the spark plug to see if it is the source of the problem.
To check the spark plug, first remove the spark plug wire from the spark plug. Then, use a spark plug wrench to remove the spark plug from the engine. Inspect the spark plug for any signs of damage, such as a cracked porcelain insulator, a damaged electrode, or excessive carbon buildup. If the spark plug is damaged or worn out, it should be replaced.
When replacing the spark plug, it is important to choose the correct type of spark plug for your Stihl string trimmer. The owner’s manual will provide information on the correct spark plug to use. Be sure to properly gap the spark plug before installing it, as an incorrectly gapped spark plug can cause starting and running problems.
Regularly maintaining and replacing the spark plug in your Stihl string trimmer is important for ensuring optimal engine performance. It is recommended to replace the spark plug every 50 hours of operation or at least once per season.
Solution: Replace the spark plug and ensure it is gapped correctly.
Dirty Carburetor: The carburetor is responsible for mixing fuel and air to create the combustible mixture for the engine. A dirty or clogged carburetor can prevent fuel from reaching the engine, causing it to fail to start.
A dirty carburetor can be a common cause of a Stihl string trimmer not starting. The carburetor is responsible for mixing air and fuel in the proper ratio to create combustion. Over time, dirt, debris, and old fuel can clog the carburetor and restrict the flow of fuel and air.
When the carburetor is dirty, the engine may not receive the correct amount of fuel or air, making it difficult to start or causing it to stall during operation. Symptoms of a dirty carburetor can also include rough idling, reduced power, and increased fuel consumption.
Cleaning the carburetor is a relatively simple process but requires some disassembly of the trimmer. The first step is to remove the air filter cover and air filter to access the carburetor. Once the carburetor is exposed, it can be removed from the engine and disassembled.
Using carburetor cleaner and a soft-bristled brush, the carburetor can be cleaned of any dirt or debris that may be clogging it. Pay particular attention to the small passages and jets that can be easily clogged. Be sure to also clean the fuel filter and fuel lines to ensure there are no obstructions.
Once the carburetor is clean, reassemble it and reinstall it on the engine. It is recommended to also replace the carburetor gasket to ensure a proper seal. Start the engine and adjust the carburetor as needed to ensure it is running smoothly.
Regular maintenance of the carburetor, such as cleaning it annually or after extended periods of non-use, can help prevent future starting problems and keep the Ryobi string trimmer running smoothly.
Solution: Clean or replace the carburetor as needed.
Old Fuel: Fuel that has been sitting for an extended period can break down and restrict the fuel supply, causing the engine to fail to start.
Old fuel is a common problem for all types of power equipment, including Stihl string trimmers. Over time, the gasoline in the fuel tank can break down and lose its potency, which can lead to starting problems and poor performance.
The shelf life of gasoline is typically around 30 days, after which it starts to degrade and lose its ability to ignite properly. In addition, gasoline can attract moisture, which can lead to corrosion and other issues with the fuel system.
When old fuel is left in a Stihl string trimmer for an extended period, it can cause the fuel lines and carburetor to become clogged with varnish and other deposits. This can restrict the flow of fuel to the engine and make it difficult to start or run properly.
To avoid problems with old fuel, it’s important to use fresh gasoline and mix in the correct amount of oil for your Stihl string trimmer. It’s also a good idea to empty the fuel tank and run the trimmer dry at the end of each season to prevent the fuel from sitting in the system for an extended period.
If you suspect that old fuel is causing problems with your Stihl string trimmer, you can try adding a fuel stabilizer to the tank or draining and replacing the fuel altogether. It may also be necessary to clean the carburetor and fuel lines to remove any buildup of varnish and other deposits. In some cases, it may be best to take the trimmer to a professional for servicing to ensure that all components are cleaned and properly adjusted for optimal performance.
Solution: Drain the old fuel and replace it with fresh fuel.
Incorrect Fuel Mix: Stihl string trimmers require a specific fuel mix of gasoline and oil. Using the wrong mix or using straight gasoline can cause engine damage and prevent it from starting.
Using an incorrect fuel mix for a Stihl string trimmer can cause starting issues and damage to the engine. Stihl string trimmers typically use a 2-cycle engine, which requires a specific oil and gas mixture to function properly.
The most common mix ratio for Stihl string trimmers is 50:1, which means 50 parts gasoline to 1 part oil. However, some older models may require a different ratio, such as 40:1 or 32:1. It is important to check your operator’s manual or the original fuel cap for the correct mix ratio for your specific model.
If the fuel mixture is incorrect, it can cause the engine to run lean or rich. Running lean means there is not enough fuel in the mixture, which can cause the engine to overheat and seize up. Running rich means there is too much fuel in the mixture, which can cause fouled spark plugs and excessive carbon buildup.
To avoid starting issues and engine damage, it is important to mix the fuel and oil correctly. Use only high-quality, unleaded gasoline with a minimum octane rating of 89. Mix the oil and gas thoroughly in a separate container before adding it to the fuel tank. Use only Stihl-approved 2-cycle oil or a high-quality, synthetic oil that meets the specifications for your engine.
If you accidentally use an incorrect fuel mix, drain the fuel tank and refill it with the correct mixture. It may also be necessary to clean or replace the spark plug and carburetor to ensure proper engine function. Consult your operator’s manual or a professional for assistance if needed.
Solution: Refer to your operator’s manual to ensure you are using the correct fuel mix for your Stihl string trimmer.
By maintaining and regularly checking these key components, you can ensure your Stihl string trimmer starts up and operates as it should. As a professional lawn care team, we rely on our Stihl string trimmers to get the job done right the first time.
