String-trimmer care

At as little as $60 to $80, competent gas and corded electric string trimmers also cost less than mowers, tractors, and other machines. (See our string trimmer Ratings and recommendations.) While that often makes buying a new trimmer more feasible than repairing a broken one, the right care can help stave off both scenarios.

Electric trimmers need little beyond periodic checks to be sure that straps, handles, and bolts are secure. But trimmers with a gasoline engine need regular upkeep to maintain their superior cutting power. Here's what to do and when:

When the yard-care season begins:

• Replace the cutting line with fresh line at the start of each season. Many cutting lines age quickly and become brittle so that they break more easily, requiring repeated line feed. Fresh line holds up better.
• Replace the spark plug on gas-powered trimmers.
• Carefully balance the trimmer by setting the handles so they're comfortable for trimming or edging. Make sure the debris shield over the cutting line is free of cracks and other damage; replace the shield if needed.
• Most gas string trimmers use two-stroke engines that require a mix of fuel and oil. Check your owner's manual for the proper ratio. Craftsman and Troy-Bilt are among the few brands that have offered four-stroke trimmers with a separate oil reservoir. Check that the oil-dipstick level is at or near the full mark. Add more if needed, but don't overfill. Too little oil can damage or destroy the engine by leaving parts unlubricated; too much can also underlubricate by causing air bubbles.

During the season:

• For gas trimmers, be sure intake vents near the air filter are clear of debris so that the engine runs efficiently.
• Clean or replace a gas trimmer's air filter as needed--more frequently in dry, dusty environments.
• Some gas trimmers have a centrifugal clutch that keeps the cutting head from spinning until you squeeze the throttle. (You can tell by looking at the head when you start the engine.) On these, the carburetor idle speed should be slow enough so that the cutting head doesn't turn.

Before winter storage:

• Add stabilizer to the fuel and run the engine to distribute the stabilized mixture through the fuel lines and carburetor.
• Thoroughly clean outer surfaces and clear all intake and exhaust vents of debris.
• Remove a gas trimmer's spark plug and pour an ounce of oil into the cylinder. Slowly pull the starter cord to distribute the oil on moving parts and help prevent rust. Then reinstall the plug.
• Hang or store the trimmer in a clean, dry area according to manufacturer's directions.