Check a trimmer running slowly ID: lst300-slow Version: 2.0.0 Model: BLACK+DECKER LST300 · US · AF-100 Region: US Parts: Automatic-feed head with AF-100 spool; match model and tool type to manual Not covered: LST420 / LSTE525; GH corded models; Dual-line heads; Metal line or blades; Nonmatching tool type or modified head; Unknown tool type or missing exact-type manual; Bump-feed conversion MATCH YOUR VERSION Model and tool type: LST300 and the exact type on my label match my manufacturer manual and figures Remove the battery before finding the label. Use the manufacturer model-and-type lookup; this site does not infer a type number from LST300 alone. Cutting head: Original AF-100 automatic-feed single-line head Do not substitute a bump-feed procedure, dual-line spool or metal cutting attachment. PREPARE [ ] Release the trigger, let the head stop, engage the lock-off and remove the battery. Leave it removed throughout hands-on care. Keep fingers away from the sharp cutter on the guard. [ ] Read LST300 and the tool type from the label. Open the official model/type lookup and compare its manual and parts figures with your actual guard, single-line head and AF-100 spool. A readable model name alone does not establish the type. If the exact type manual cannot be obtained, or any figure differs, save a preparation record and stop. [ ] Tool: Good lighting [ ] Tool: Scissors for nylon only [ ] Material: No replacement material needed for an intact tool STOP Keep the battery removed if the exact type/manual match is unknown or parts differ from the figures. Stop for a damaged battery, exposed wiring, a faulty switch, cracked guard, broken spool/hub, damaged cap tabs or housing slots. Use an authorized service center. Never open the battery, motor housing or charger. CONSUMABLE FIT CHECK ROUTE safety: Is the battery removed, the trigger released and the cutting head stopped, with no battery damage, exposed wiring or faulty switch? Yes -> compatibility: Keep the battery removed for every hands-on step. No -> service: Stop using the tool for electrical, battery or switch damage. If you have only omitted battery removal, make the tool safe before restarting. Not sure -> prepared: Keep the battery removed. Save your preparation record and check the matching manual before continuing. compatibility: Have you matched the label LST300 AND its exact tool type to the official lookup manual and its figures, with the original AF-100 automatic single-line head? Yes -> check-1: Record the label type and matching manual reference in the first step. No -> prepared: An unknown type, unavailable type manual, different figures, bump-feed head or dual-line conversion blocks this procedure. Use manufacturer support to identify the correct instructions. Not sure -> prepared: Keep the battery removed. Save your preparation record and check the matching manual before continuing. check-1: Did the tool run slowly without burning smell, smoke, damaged wiring or battery damage? Yes -> check-2: Check only the manual’s accessible mechanical causes. No -> service: An electrical or battery warning ends this external check. Not sure -> prepared: Keep the battery removed. Save your preparation record and check the matching manual before continuing. check-2: Are the guard and cap secure enough to inspect the head safely? Yes -> steps: Check the stopped housing and line length. No -> service: Repair damaged retention parts before any operation. Not sure -> prepared: Keep the battery removed. Save your preparation record and check the matching manual before continuing. CARE STEPS (only when the route reaches steps) [ ] 1. Record the exact tool and make it safe Release the trigger, let the head stop, engage the lock-off and remove the battery. Leave it removed throughout hands-on care. Keep fingers away from the sharp cutter on the guard. Read LST300 and the tool type from the label. Open the official model/type lookup and compare its manual and parts figures with your actual guard, single-line head and AF-100 spool. A readable model name alone does not establish the type. If the exact type manual cannot be obtained, or any figure differs, save a preparation record and stop. Look for: The battery is physically separate from the tool; your label type and matching manual reference are written below. Source: bd-manual-help, Official model/type lookup instructions; type is beside or below the model number [ ] 2. Note the symptom before cleaning Record when slow running occurred and whether long line or heavy grass was visible. Keep the battery out throughout the inspection. Slow running alone does not identify a battery or motor failure. Look for: The original symptom is recorded before any change. Source: lst300-manual, English p10 Trimmer runs slowly [ ] 3. Check the stopped spool housing Carefully check whether the spool housing rotates freely as the manual instructs, with hands clear of the guard cutter. Do not force a seized housing or use pliers on the head. Look for: Movement is free or binding is clearly recorded; no powered test is used for this check. Source: lst300-manual, English p10 Trimmer runs slowly [ ] 4. Clear accessible material Carefully remove loose dirt or grass that is restricting the accessible housing. If it cannot be cleared gently, stop for service. Use the housing-cleaning task for dirty external air slots. Look for: Only accessible debris has been removed; an internal obstruction is not pursued. Source: lst300-manual, English p10 Trimmer runs slowly [ ] 5. Correct excessive line length Check the nylon projection against the manual’s approximate 5-3/8 inches (136 mm). If it is excessive or reaches past the guard cutter, use scissors to cut it so it just reaches the cutter. Avoid the blade itself. Look for: The line reaches no farther than the cutter and is still the specified round nylon. Source: lst300-manual, English p10 Trimmer runs slowly [ ] 6. Record the unpowered result Record whether free movement and line length were restored. Keep the battery out and complete after-care before normal use. If the housing binds or slow running recurs, end the test and request service. Look for: The saved result states the external checks and does not claim an internal diagnosis. Source: lst300-manual, English p10 Trimmer runs slowly OBSERVATIONS Tool type exactly as printed on the label (required): ____________________ Exact-type manual reference or link that you matched (required): ____________________ When the slow-running symptom occurred (required): ____________________ Head movement after the check (required): ____________________ Choices: Moves freely / Still binds; service needed [service required] Result of this task (required): ____________________ Choices: Checks passed; ready for the stated next step / More preparation or a linked task is needed [further care/preparation needed] / Leave unused and contact service [service required] RESULT CHECKS [ ] The stopped spool housing moves freely after any accessible debris is removed. [ ] Excess nylon is corrected; persistent binding or slow running leads to service. NEXT CARE Trimmer runs slowly Inspect when the stated condition occurs. The manual gives no fixed day or month interval. Basis: manufacturer Source: lst300-manual, English p10 Trimmer runs slowly Record preparation, maintenance readiness, problem located or service needed. This is not proof of a physical repair. SOURCES BLACK+DECKER LST300 instruction manual (manufacturer document, retailer-hosted) https://pdf.lowes.com/productdocuments/1935f26b-7448-4c95-b467-a223bb73d80f/63056925.pdf English p10 Trimmer runs slowly Checked: 2026-10-13 Manufacturer copyright, hosted by Lowe’s. Facts paraphrased; no diagrams or manual redistributed. BLACK+DECKER: locate a manual using model and type number https://support.blackanddecker.com/hc/en-us/articles/360012700118-How-can-I-get-a-parts-list-or-manual-for-my-tool Official model/type lookup instructions; type is beside or below the model number Checked: 2026-10-13 Linked only. BLACK+DECKER LST300 product and support https://www.blackanddecker.com/products/lst300 LST300 model identity; Automatic Feed Spool; Includes AF-100 Checked: 2026-10-13 Linked only; no product photos reused.