Introduction
Restringing a Black and Decker weed eater is a routine maintenance task that keeps your trimmer cutting cleanly and efficiently. Whether you own a classic spool‑feed model or a newer bump‑feed version, the process is straightforward once you understand the parts and the proper technique. This guide walks you through every step, from identifying your model to troubleshooting common line‑feed problems, so you can get back to yard work with confidence.
Table of Contents
- Introduction
- Understanding Your Black and Decker Weed Eater
- Tools and Materials Needed
- Safety Precautions
- Step‑by‑Step Restringing for Spool Models
- Step‑by‑Step Restringing for Bump Feed Models
- Comparison Table: Spool vs. Bump Feed
- Common Mistakes to Avoid
- Maintenance Tips for Longer Line Life
- Troubleshooting Line Feed Issues
- Frequently Asked Questions
- Conclusion
Understanding Your Black and Decker Weed Eater
Black and Decker offers a range of string trimmers, each with a slightly different line‑loading mechanism. Knowing which system your unit uses is the first step in a successful restring.
Model Types
Most current Black and Decker trimmers fall into two categories: spool‑feed and bump‑feed. Spool‑feed models house a pre‑wound spool that you replace entirely, while bump‑feed models use a reusable head that you wind with fresh line. Older “auto‑feed” units may combine elements of both, but the basic principles remain the same.
Spool vs. Bump Feed
A spool‑feed head is a sealed cartridge; you simply pull the old spool out and snap a new one in. This design is fast but can be more expensive over time because you purchase whole spools. A bump‑feed head has a removable cover, a spool hub, and a spring‑loaded bump knob. You wind line onto the hub yourself, which gives you control over line length and diameter, and typically costs less per foot of line.
Tools and Materials Needed
Before you begin, gather the following items so the job proceeds without interruptions:
- Replacement trimmer line (match the diameter recommended in your owner’s manual, usually .065‑.095 in)
- New spool cartridge (if you have a spool‑feed model)
- Scissors or a sharp utility knife
- Work gloves to protect your hands from sharp line ends
- Safety glasses
- Flat‑head screwdriver (only needed for some bump‑feed heads that use a screw to secure the cover)
- Clean rag for wiping debris from the head
Safety Precautions
Always treat a string trimmer as a power tool. Follow these safety steps before you start:
- Disconnect the power source – unplug corded units, remove the battery from cordless models, or ensure the gas engine is off and the spark plug wire is detached.
- Wear safety glasses and gloves; trimmer line can snap and cause eye or skin injuries.
- Work on a stable, flat surface with good lighting.
- Keep children and pets away from the work area.
- Never attempt to restring while the motor is running or the battery is installed.
Step‑by‑Step Restringing for Spool Models
Spool‑feed trimmers are the quickest to service because the entire line assembly is a single cartridge. Follow these steps carefully.
Remove the Old Spool
Locate the spool release button on the trimmer head – usually a small tab on the side of the housing. Press the tab while gently pulling the spool straight out. If the spool is stuck, wiggle it slightly; do not force it, as the plastic housing can crack.
Cut the New Line (If Using a Refill Spool)
Some spool‑feed models accept a refill spool that you wind yourself. If you have a refill, cut a length of line about 10‑12 feet long. This gives you enough material to wind the spool fully without running short.
Wind the Line onto the Spool
Insert one end of the line into the anchor hole on the spool hub. Hold the spool steady and wind the line in the direction indicated by the arrow on the spool (usually clockwise). Keep the wraps tight and even, avoiding overlaps. Continue until the spool is full but not bulging; over‑filling can cause the line to jam during operation.
Reinstall the Spool
Align the spool’s notches with the guide slots in the head housing. Push the spool in until you hear a click, confirming the release tab has engaged. Give the spool a gentle tug to verify it is locked in place.
Step‑by‑Step Restringing for Bump Feed Models
Bump‑feed heads require a bit more hands‑on work, but they let you choose line length and diameter. The procedure below covers the most common Black and Decker bump‑feed design.
Open the Bump Head
Turn the bump knob counter‑clockwise until it stops. On some models you may need to press a small release latch while turning. Once the knob is free, lift the cover off the head. Set the cover and knob aside on a clean rag.
Insert and Wind the New Line
Cut two equal lengths of line, each about 9‑10 feet long. Insert one end of the first piece into the upper anchor hole on the spool hub, and the second piece into the lower anchor hole. Wind both lines simultaneously in the direction shown by the arrow on the hub (typically clockwise). Keep the lines separated in their respective channels; crossing them will cause feeding problems. Stop winding when the spool is about 80 % full – leave a small gap to allow the bump mechanism to advance line.
Close the Head and Test
Replace the cover, aligning any tabs or grooves. Turn the bump knob clockwise until it clicks into the locked position. Reattach the battery or plug in the unit. Start the trimmer and gently tap the bump knob on the ground; the line should advance a few inches each tap. If the line does not feed, reopen the head and verify that the lines are seated correctly in their channels.
Comparison Table: Spool vs. Bump Feed
| Feature | Spool‑Feed | Bump‑Feed |
|---|---|---|
| Line replacement speed | Very fast – swap whole cartridge | Moderate – wind line manually |
| Cost per foot of line | Higher (pre‑wound spools) | Lower (bulk line spools) |
| Line diameter flexibility | Fixed by cartridge | Choose any compatible diameter |
| Risk of line jam | Low (sealed cartridge) | Higher if wound incorrectly |
| Typical models | Black & Decker LST136, LST300 | Black & Decker LST420, LST520 |
Common Mistakes to Avoid
Even experienced users can slip up. Keep these pitfalls in mind:
- Using the wrong line diameter – Too thick a line stalls the motor; too thin a line breaks quickly.
- Over‑filling the spool – Excess line creates friction and prevents the bump mechanism from advancing.
- Crossing the two lines in a bump head – This causes uneven feed and frequent tangles.
- Forgetting to disconnect power – A sudden start can cause serious injury.
- Neglecting to clean the head – Grass buildup can block the line path and wear the bump spring.
Maintenance Tips for Longer Line Life
Proper care extends the interval between restringing sessions:
- Trim only dry grass when possible; wet vegetation wraps around the line and accelerates wear.
- Keep the trimmer head clean – brush out clippings after each use.
- Store the trimmer in a dry place; moisture can cause the line to become brittle.
- Inspect the bump spring periodically; a weakened spring reduces line advance.
- Use high‑quality, UV‑resistant line; cheap line degrades faster under sunlight.
Troubleshooting Line Feed Issues
If the line refuses to advance or cuts poorly, run through this checklist:
- Line not feeding – Verify the bump knob moves freely; lubricate the spring with a light silicone spray if it feels stiff.
- Line breaks immediately – Check for sharp edges inside the head; file down any burrs.
- Uneven line length – Re‑wind the spool ensuring both lines are equal length and seated in separate channels.
- Motor bogs down – Confirm you are using the correct line diameter; a thicker line increases load.
- Head vibrates excessively – The spool may be unbalanced; re‑wind with even tension.
Frequently Asked Questions
How often should I restring my Black and Decker weed eater?
Frequency depends on usage. For a typical residential yard, restringing every 2‑3 hours of cutting time is common. Heavy‑duty or commercial use may require restringing after each session.
Can I use any brand of trimmer line?
Yes, as long as the diameter matches the specification in your owner’s manual. Using a reputable brand ensures consistent quality and reduces breakage.
Why does my bump head not advance line when I tap it?
The most common cause is a jammed or weak bump spring. Open the head, clean any debris, and test the spring tension. If the spring is damaged, replace the bump knob assembly.
Is it okay to mix line diameters on a bump‑feed head?
No. Both channels must use the same diameter; mixing sizes leads to uneven feed and premature line failure.
What line diameter is best for thick weeds?
A .095 in line provides more cutting power for dense vegetation, but it also draws more current from the motor. Check your model’s maximum recommended diameter before upgrading.
Conclusion
Restringing a Black and Decker weed eater is a simple yet essential skill that keeps your trimmer performing at its best. By identifying whether you have a spool‑feed or bump‑feed model, gathering the right tools, and following the step‑by‑step instructions above, you can replace the line quickly and safely. Remember to observe all safety precautions, avoid common mistakes, and perform regular maintenance to extend the life of both the line and the trimmer head. With a fresh spool or a properly wound bump head, you’ll be ready to tackle any overgrown edge with clean, precise cuts.