Diagnosis
Excessive, unusual vibration is transmitted through the shaft and handle. This is caused by an unbalanced rotating assembly.
How to Fix It
Checklist. 1: Remove the trimmer head spool and inspect for uneven line wear or a broken/missing line segment. Replace line evenly. 2: Ensure the spool is seated correctly and the retaining mechanism is fully tightened. 3: Check that the debris shield is secure and not touching the spinning line. 4: Inspect the trimmer head for physical damage or cracks. If vibration persists, proceed.
If That Didn't Work
The issue may be in the gearbox or motor. A bent output shaft or damaged internal bearing will cause severe vibration. This requires disassembly and service by a technician.
Heads Up
Continued use with high vibration can loosen internal components, damage the gear coupling, and cause accelerated wear. It also increases user fatigue and reduces control.