String Trimmer Maintenance

String Trimmer Maintenance

Level: Experienced

String trimmers, also known as “weed whackers,” “weed eaters,” “weed whips” and a host of other names, are essential lawn tools and should be as big a part of a lawn care arsenal as a lawnmower. While the lawnmower usually does most of the heavy lifting, the string trimmer cuts down all the grass that the mower can’t reach along hardscaping edges, around trees and other objects. This is a handy guide on how to maintain your string trimmer and use it safely to make your yard a manicured marvel.

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  • Maintain a String Trimmer

    Properly maintaining your string trimmer is essential. While both gas-powered and electric models require some effort to keep them in prime running condition, the two types do require different amounts of maintenance. Because of its engine, a gas-powered model requires more upkeep. Corded electric models and models with rechargeable lithium-ion batteries are convenient because they don’t require fuel, oil or spark plugs. Depending on your particular lawn care needs, however, electric models may not supply the amount of power required to cut through heavier growth. So keep that in mind and weigh your specific needs before purchasing.

    • Step 1: Clean and Inspect the Trimmer

      Clean the string trimmer to keep it performing well. Dust, grime and caked-on grass clippings build up on the debris shield and trimmer head and can lead to inefficiency and possible malfunction if not cleaned. Wipe the trimmer parts down with a rag after use and before storing it. Do a deeper cleaning with a stiff brush and a damp cloth periodically. Use cotton swabs, lightly dampened with machine oil to clean exhausts and intakes and other hard-to-clean areas.

      Helpful Tip

      Use an air compressor or a can of compressed air to blow air into the trimmer engine vents and crevices to remove dirt and dust from inside.

      Remember to inspect your string trimmer for any signs of wear or damage when you’re cleaning it.

      Safety Alert!

      Before cleaning or maintaining your string trimmer—particularly when handling the business end—always remove the spark plug from a gasoline-powered unit. Unplug the power cord or detach the battery from an electric unit.

      Helpful Tips

      Store your trimmer and accessories somewhere where they will be protected from dust and moisture, preferably in a garage or tool shed. This not only keeps them protected, it also keeps them organized so you can easily find the tool you need when you need it.

      Remember to keep the instruction manual. Not only is it a great guide and resource on how to properly and safely use your string trimmer, the manual also has valuable information on how to care for it, find replacement parts and other important pieces of information.

    • Step 2: Replace Trimmer Line
      trimmer line

      No matter if your trimmer model is gas-powered or electric, both require replacement of the trimmer line periodically. The type of head on your trimmer does determine how you replace the line though. You will most likely have a single or dual-line head. This means that there will be one or two protruding pieces of line for cutting. Follow the instructions from your trimmer’s manufacturer on how to replace the line.

      Helpful Tips

      Keep surplus trimmer line around so that you don’t run out and have to stop working to go buy more.

      When replacing the trimmer line, take this time to clean the trimmer head. Use a damp rag to remove caked on grass and debris.

    • Step 3: Check/Change Oil and Fuel

      If you’re using a gas-powered string trimmer, you need to maintain its engine by considering its fuel/oil requirements. Gas-powered string trimmers use oil and gasoline to function, with some using a fuel/oil mixture, depending on the type of engine. Four-cycle engines have separate gas and oil reservoirs, while 2-cycle engines operate on a mixture of gasoline and 2-cycle engine oil.

      Consult the manufacturer’s instructions on the proper fuel/oil ratio (typically 50:1 or 40:1) if you own a trimmer with a 2-cycle engine. Use a funnel to pour the fuel and 2-cycle oil into a small gas can to mix them together at the correct ratio. Fill the trimmer’s fuel reservoir when needed.

      When using a 4-cycle trimmer, check fuel and oil levels before each use. Remove the spark plug before doing any maintenance. This will ensure the trimmer is completely deactivated. Your particular trimmer model will determine how you can check its oil level. Some models will have an oil level window, or a dipstick; in lieu of either of those, you can simply open the oil reservoir and peer inside to check the oil level. Shine a flashlight on the opening if you need help seeing inside. Fill the reservoir with the manufacturer-recommended type and amount of oil when needed. Use a funnel for spill-free filling.

      As with a motor vehicle, the oil will turn dark when it‘s time to change it. Remove the reservoir plug and position the trimmer so that the old oil will drain into an oil pan or another container. Once all of the oil has drained, use a rag to clean up anything that spilled and then fill the reservoir with the appropriate oil type by pouring the oil through a funnel into the oil reservoir. Check the oil level again to ensure that the proper amount has been added and then close the reservoir by inserting its plug .

    • Step 4:Check/Replace Air Filter

      Gas-powered models also require that you check the engine air filter. Read the manufacturer’s instructions to determine where your air filter is located and how to access it. Check to see if the filter is covered with dust and debris. Some filters are washable and reusable. Check your owner’s manual for instructions on how to clean the filter. If the filter is unsalvageable or damaged, replace it.

    • Step 5: Store Trimmer Appropriately

      Where and how you store your string trimmer when not in use is essential to keeping it in prime working order. Store your trimmer in a well-ventilated tool shed or garage, out of the elements. Do not store gas or gas/oil mixtures for the trimmer inside your home or basement. Fumes can build up and create a dangerous situation. Be sure that the trimmer and other tools are not accessible by children.

      Wait for the engine to cool before putting the trimmer away. When storing your trimmer at the end of the season, remove all dirt, grease and debris from the trimmer using a stiff-bristle brush. Tighten all screws and nuts. Drain the fuel tank, remove the spark plug and add a small amount of oil into the cylinder. Pull the starting cord a couple of times to distribute the oil. Reinstall the spark plug, but don't connect the ignition cable.

    String Trimmer Safety

    In addition to maintaining your trimmer, you also need to know how to operate it safely. Follow these tips on how to use your string trimmer safely and efficiently to keep your landscape neat and trim.

    • Use Proper Technique

      Using a string trimmer properly is the first step in keeping yourself and others safe during operation. Keep an eye out for any people or pets around where you’re working. String trimmer line spins at high velocity and can pick up rocks and other debris and fling them at high speed. If someone approaches your vicinity, stop cutting until they have passed. Keep an approximate 50 feet between yourself and any bystanders. Do not remove debris shields and other safety features built into your trimmer. Always cut away from yourself.

      When refilling fuel or oil, or when starting a gas-powered trimmer, place the machine on the ground. To start a gas-powered trimmer, pump the primer bulb to feed gas to the engine, turn on the choke and then pull the starter cord. Once the unit is operating, lift it, adjust the choke and let it run for about a minute to warm up.

      Keep the engine of the trimmer at waist level with the head of the trimmer parallel to the ground. Move the trimmer from side to side along the area to be cut. Always ease into the cut, so that you don’t cut too much, or damage something you’re not trying to cut. Keep in mind that string trimmers are meant to cut grass and similar growth; don’t use a string trimmer to cut thicker growth. It probably won’t work well—you will waste trimmer line and put strain on the trimmer engine. To get the best results, keep an eye on your trimmer line to be sure it is protruding at an effective length for cutting. Depending on your trimmer model, the line may spool out automatically as it is cuts, then wears and breaks off. If your trimmer head does not have an automatic line feed, you may need to pull it out by hand to the right length. Be sure you have turned off the trimmer beforehand.

    • Wear Safety Equipment

      Dress properly and wear safety equipment to protect yourself from potential injury from flying debris. Wear long pants, long sleeves and work gloves. Wear safety glasses to protect your eyes. Gas-powered models can be very loud when operating and cutting. Wear earplugs to protect your ears .

      Great job! Now you know how to maintain and safely use your string trimmer.

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