How to Maintain Your String Trimmer

With a few simple steps every now and then, you can keep your string trimmer trimming for years to come.

Cleaning the Air Filter

Just like in your car, a clean air filter improves performance and prevents engine damage.

1. Make sure the string trimmer engine is off and cool to the touch. Open the filter cover and remove the air filter.

2. Wash it in detergent and water. Rinse it and let it dry.

3. Lightly coat the filter with clean motor oil to keep debris from getting sucked into the engine. Squeeze the air filter to distribute the oil, and to remove any excess.

4. Put the filter back in the trimmer and close the filter cover until the lock tab snaps into place.

Replacing the String Trimmer Spark Plug

Your string trimmer’s spark plug will only last so long – check it at least once a season.

1. Make sure the engine is off and cool to the touch. Then remove the spark plug boot and clean around the area, then remove it with a 5/8-inch socket – check to see if it’s fouled, blackened, corroded or damaged.

2. If needed, replace it with the model specified for your trimmer – use a feeler gauge to set the gap according to the manual – don’t over tighten.

3. Finally, put the spark plug boot back on.

Replacing the grass trimming line

When you come to the end of the line, get familiar with the string trimmer parts and follow these steps and you’ll be back to trimming in no time.

Step 1: Removing the inner reel

• Hold the outer spool with one hand and unscrew the bump knob counterclockwise.
• Make sure the bolt inside moves freely. If the bump knob’s damaged, replace it.
• Remove the inner reel from the outer spool, and then remove the spring from the inner reel.
• Use a cloth to clean the inner reel, spring, shaft and inside of the spool.
• Check the indexing teeth and holding slots for wear. If they’ve seen better days, replace the inner reel, outer spool or both.

Step 2: Winding line onto the reel

If you’re using a new prewound inner reel, go ahead and skip to step 3. If you’re winding the line yourself, you’ll be using either single line or split line. Let’s go over the winding process for both.

Option 1: Winding single line

1. To wind a single line, first cut a 12-foot length of new line. Fold the line in half to create a loop in the middle.

2. Insert the loop into the slot in the split wall.

3.Wind the line tight in the direction shown on the bottom of the inner reel until about 6 inches of line remains. Keep the top half of the line above the split wall and the bottom half of the line below the split wall.

4. Insert the two 6-inch sections into the two holding slots. Now you’re ready to reinstall the inner reel.

Option 2: Winding split line

1. If you’re doing a split line, cut a 6-foot length of new split line. Split each end about 6 inches.

2. Using one split end, insert one line into the top hole and the other line into the bottom hole in the inner reel.

3. Wind the line tight in the direction shown on the bottom of the inner reel. That split wall will divide the line on its own. Wind until it’s completely divided and you’ve got about 6 inches of line left.

4. Insert the two 6-inch sections into the two holding slots. Now you’re ready to reinstall the inner reel.

Step 3: Installing the inner reel

1. Place the spring inside the inner reel and insert the inner reel into the outer spool. Push the inner reel and outer spool together.

2. Pass the two line ends through the eyelets in the outer spool.

3. While holding the inner reel and outer spool together, firmly pull the two line ends to release them from the holding slots.

4. While holding the inner reel and outer spool together, screw on the bump knob. Done.

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