How It Works: String Trimmer


String trimmer won’t start, runs poorly or line won’t feed? This video provides information on how a string trimmer works and offers troubleshooting tips to assist you in diagnosing and repair.

Here is a list of the most commonly replaced parts associated with each string trimmer symptom:

String trimmer won’t start: spark plug, carburetor, rewind pulley and spring, fuel filter
String trimmer engine stops after a few seconds: spark arrestor, carburetor, fuel filter, air filter
String trimmer runs poorly: carburetor, fuel filter, air filter, spark plug, spark arrestor
String trimmer head won’t spin: clutch, drive shaft, trimmer head, throttle cable
String trimmer head won’t stop spinning: clutch
String trimmer string line won’t feed: trimmer head, trimmer line, trimmer housing

All of the information provided in this string trimmer troubleshooting video is applicable to the following brands: Craftsman, Echo, Homelite, Mantis, Poulan Pro, Ryobi, Stihl, Toro, Troy-Bilt, Weedeater.

RepairClinic has millions of replacement parts for appliances, lawn equipment, power tools, and heating & cooling equipment including washers, dryers, dishwashers, refrigerators, lawn mowers, snowblowers, furnaces, and air conditioners. Our customer care team is available to help by phone or live chat, seven days a week: 1-800-269-2609. We guarantee the fastest shipping possible—all in-stock parts ship the same business day. Return any part for any reason with our generous 365-day return policy.

In addition to providing replacement parts, offers free online troubleshooting information and DIY repair videos. Use our website to choose from a series of problems to discover the likely causes and the correct replacement part(s) for your particular model. Once you’ve determined the solution, our expertly-produced video tutorials will guide you through every step of the repair.

At RepairClinic, we make fixing things easy!
1Maintenance tips for your string trimmer
Maintenance tips for your string trimmer
String trimmers enable homeowners to give their yards a well-manicured look. Proper maintenance will maximize efficiency and prevent problems.
2Change the fuel filter.
Change the fuel filter.
In most models, fuel filters can be removed and cleaned. Some fuel filters are located in the fuel line and others are located inside the fuel tank. Be sure to consult your owner’s manual for information about this. If you find debris clogging the mesh screen inside the filter, replace it.
3Clean/replace the spark arrestor
Clean/replace the spark arrestor
Located inside the string trimmer engine’s muffler, the spark arrestor has an important role in the proper functioning of the string trimmer. It should be cleaned or replaced every 25 hours of use or once a season. Note that if your model has a fiberglass spark arrestor, it should be discarded and replaced every 25 hours of use, as this type cannot be cleaned and reused.
4Replace the cutting line.
Replace the cutting line.
Over time, string trimmer line weakens, becomes brittle and easily breakable. Use a high quality, non-rounded string for a dramatically better cut. Enter your string trimmer model number to find replacement string trimmer line.
5At the end of the season, degrease.
At the end of the season, degrease.
Before storing your string trimmer at the end of the season, spray a degreaser on greasy and dirty areas. Let it sit for 10-15 minutes before wiping the sprayed area with a clean cloth. Rinse it off and ensure that it’s completely dry before storing the string trimmer.

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