How to Troubleshoot a Toro String Trimmer

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When your Toro string trimmer won't start or otherwise experiences problems, working through a few troubleshooting steps can help you diagnose the problem and find the right solution. Before you think the worst — that there's a major problem with your string trimmer — it may be comforting to know that most issues are easily resolved with a little DIY tweaking.


Here are the most common issues with a Toro string trimmer — and how to fix them.

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Before operating, maintaining, or repairing your string trimmer, observe all safety precautions outlined in your user manual. Be sure to wear protective equipment, including eye protection (eyeglasses or safety glasses), rubber gloves and long pants. If you have an electric trimmer, don’t forget to unplug it before making any adjustments or repairs.

Battery-Powered Trimmer Won't Start

When something prevents the transfer of power from the power source to the working parts of a Toro string trimmer, where you'll target your troubleshooting depends on what type of trimmer you have. If you have a cordless trimmer that won't start, check to make sure that the battery pack is fully charged and that it's properly locked in place. You may need to replace the battery pack if it no longer works.


Gas-Powered Trimmer Won't Start

If you have a gas-powered trimmer, check the air filter and the fuel filter. Both of these components can become clogged over time, which causes the trimmer to operate sporadically or not to start at all. If either filter is clogged, you'll need to replace it. If the fuel filter is clogged, drain the old fuel from the tank and refill with new fuel (use fresh gas unless the fuel you have has been stabilized), then replace the fuel filter.


The Carburetor Is Clogged

Old fuel left in the trimmer's tank may partially evaporate, leaving a sticky substance that clogs the carburetor, eventually preventing the trimmer from starting. Instead of replacing the carburetor as a first measure, try cleaning it with a carburetor cleaner. You may also need to adjust the carburetor according to the directions in your user manual.



Draining the fuel at the end of the season is the best way to prevent fuel-related problems and is an important part properly storing a string trimmer.

The Spark Plug and Spark Arrestor Are Defective

If you suspect your trimmer may have a faulty spark plug, use a spark plug tester to find out if it's defective. When you try to start the trimmer, the tester should show a strong spark between the terminals on the tester. Sometimes, you'll be able to observe obvious signs of damage without even using a tester, including cracks to the porcelain insulator or a burned electrode, which shows signs of black carbon buildup.


A spark arrestor is a different part from the actual spark plug. It's the small screen that stops errant sparks from the engine. Over time and after many starts, the spark arrestor becomes clogged with soot. This can prevent the string trimmer from starting. A simple fix is to remove the spark arrestor and clean the screen with a wire brush. You can also easily replace this part if it's in bad shape.


Whenever you replace any part on a Toro string trimmer, be sure to use replacement parts that are factory-approved. Otherwise, you may void your warranty if you use non-approved parts.



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