If you run a string trimmer, you know the frustration: you’re halfway through tidying up the yard, and suddenly the line won’t feed, or worse, the head feels sticky and sluggish. These seemingly small issues—line feed problems and a neglected gear head—are the silent saboteurs of an efficient trimming session.
Don’t let a poorly maintained head slow you down! With a little preventative maintenance, you can ensure smooth, reliable performance all season long.
🧵 The Line Feed Fiasco: More Than Just Tangled String
When your trimmer line refuses to advance, it’s rarely because the spool is magically empty. It’s usually one of three common issues:
1. Poor Winding Technique
This is the number one culprit. When reloading the spool, the line must be wound tightly and evenly.
- Do:Â Keep constant tension on the line as you wind it. Each wrap should sit right next to the previous one, like a neatly stacked spool of thread.
- Don’t: Wind loosely or cross the lines haphazardly. This creates gaps where the line can dig into itself under the stress of operation, causing it to bind and stick.
2. Using the Wrong Line
Using old, brittle, or incorrect diameter line can cause problems.
- Brittle Line: Line stored for too long or in direct sunlight can dry out. Before winding, soak the new line in a bucket of water for 24 hours. This rehydrates the nylon, making it more flexible and less prone to breaking off short or fusing inside the head.
- Wrong Diameter: Always use the line size specified in your trimmer’s manual. A line that is too thick may not fit the spool correctly and puts excessive strain on the engine.
3. Clogged Eyelets
Check the metal or plastic eyelets (where the line exits the head). If they are gummed up with dirt, sap, or melted plastic, the line can’t slide out freely.
- The Fix: Remove the eyelets (if possible) and clean them thoroughly with a small wire brush or a narrow file. If they are worn into an oval shape instead of a clean circle, replace them. Worn eyelets create friction and cause the line to break prematurely.
🔩 Gear Head TLC: The Crucial Lubrication Step
The gear head (or gear case) is the angled component at the very end of the trimmer shaft that drives the spool. It contains a set of gears that are subjected to immense heat and friction. If these gears aren’t properly lubricated, they will fail quickly, leading to an expensive replacement.
1. What to Use: The Right Grease
Do not use standard automotive grease, WD-40, or engine oil. You need a specific type of lubricant designed for high-stress gears:
- Recommended: High-pressure, moly-based grease or specific string trimmer gear grease. These are often sold in small tubes with a narrow tip.
2. How and When to Lubricate
Most modern gear heads have a small plug or grease zerk (a tiny fitting) on the housing.
| Action | Frequency | Steps |
| Inspection | Before each season | Clean the outside of the gear head. Check for any leaks or cracks in the housing. |
| Lubrication | Every 25 hours of operation or at least once per season | Remove the plug/zerk. Slowly inject the specialized grease until it just starts to ooze out of the hole. Don’t overfill! Too much grease can cause a pressure build-up that damages seals. Reinstall the plug securely. |
Pro Tip: If you notice grease leaking from the gear head seals, or if the head feels unusually hot after just a few minutes of use, stop immediately. The internal seals are likely compromised, and you need professional service before the gears are permanently damaged.
Taking a few minutes to master your line winding and giving your gear head the grease it deserves will save you hours of frustrating downtime and the cost of major repairs. Your trimmer will thank you with smooth, consistent performance!