Grass line trimmer common questions

These common questions about grass line trimmers are the ones our experts hear the most often from our customers. You might also find the help you need by checking the common symptoms and solutions for grass line trimmers. When you’re ready to make a repair, search your model number to find replacement parts. Sears PartsDirect has the part you need, no matter where you bought your grass line trimmer.

What mix of gasoline and oil should I use in my grass line trimmer?

Check your owner’s manual for the proper ratio of gasoline to oil needed for a 2-cycle line trimmer. Most models require a 40:1 ratio. To achieve that mix, add a 3.2 oz. bottle of 2-cycle oil to each gallon of gasoline.

Why won’t my line trimmer start?

Stale fuel causes most starting problems. Empty the gas tank and fill it with fresh fuel or 2-cycle gasoline/oil mix. If the trimmer still won’t start, the engine might have a clogged carburetor, failed ignition system, or lack of compression.

How do I replace the gas lines on my line trimmer?

Most trimmers have two fuel lines: a return line and a feed line. The feed line is thinner and has the fuel filter attached to one end. The filter end of the feed line fits inside the fuel tank; the other end connects to a small port on the carburetor. The larger return line connects the primer bulb to the fuel tank.You can replace them following the steps in this repair guide.

If your trimmer has a different fuel line configuration, have a service technician make the replacement.

Why won't my engine on my line trimmer idle properly?

If your line trimmer is idling poorly, the idle speed is likely set too low or too fast. You can adjust the idle speed on some line trimmer models by adjusting the idle set screw on the carburetor.  Refer to your owner's manual for instructions on adjusting the idle set screw on your line trimmer.

Why does my engine bog down or die when I start cutting grass?

If your line trimmer slows or dies when you cut grass, check the air filter. A dirty air filter can cause the line trimmer engine to die or bog down under a load. Clean or replace the air filter if it’s dirty.

If the air filter is clean, check the mounting screws on the carburetor. Loose carburetor mounting screws can cause the engine to die under a load. Tighten the carburetor mounting screws if they’re loose.

Cracked fuel lines can also cause the engine to bog down or die under a load. Replace the fuel lines if they’re cracked or damaged.

The high and low speed limits on the carburetor may need adjustment. Follow the instructions in your owner’s manual to adjust the high and low speed limit screws on the carburetor.

What causes the line trimmer engine to smoke excessively?

If the line trimmer smokes a lot, check the fuel mixture. Too much 2-cycle oil in the gasoline mixture causes excessive smoke. Most 2-cycle line trimmer engines use a 40:1 or 50:1 gasoline to oil mixture.

A dirty air filter can cause the engine in a line trimmer to smoke excessively. Clean or replace the air filter if it’s dirty.

Check the choke position on the carburetor. If the choke is partially closed, the engine can smoke excessively.

Clean and adjust the carburetor if necessary to eliminate excessive smoke.

What causes the line trimmer engine to run hot?

Incorrect fuel mixture causes the engine in a line trimmer to overheat. Check the fuel mixture. Most 2-cycle line trimmer engines use a 40:1 or 50:1 gasoline to oil mixture. Drain the fuel tank and fill it with the proper fuel mix if necessary.

The wrong type of spark plug can also cause the line trimmer engine to run hot. If you recently replaced the spark plug, make sure that you installed the correct type for your model of line trimmer.

In improperly adjusted carburetor can cause the engine in a line trimmer to overheat. Adjust the carburetor according to the guidelines in your owner’s manual if necessary to prevent the engine from overheating.

Can I use E85 fuel in my line trimmer?

E85 is a fuel combination of ethyl alcohol (ethanol) and gasoline. It contains 85% ethanol. Most line trimmer engines cannot use E85 fuel. Many line trimmers can only use unleaded gasoline with up to 10% ethyl alcohol (E10). Check your owner’s manual for fuel specifications.

Can I leave fuel in my line trimmer when stored?

Don’t leave fuel should in the gas tank if a line trimmer longer than 30 days. Stagnant fuel left in the line trimmer for more than 30 days creates gum deposits in the carburetor that clog fuel paths and prevent the engine from running smoothly. If storing the line trimmer longer than 30 days, drain the fuel tank and retighten the gas cap. Start the engine and let it run until it stops to remove all the fuel from the carburetor.

How often should I clean the air filter on my line trimmer?

Clean the line trimmer’s air filter after every 5 hours of use. Clean a foam air filter by washing it in warm, soapy water. Rinse the foam air filter with clean water and let it dry completely before reinstalling it on the engine. If the air filter is damaged, replace it.