Diagnosing What's Wrong with Your Weed Eater

A weed eater being used to trim a lawn.
What You'll Need
Weed eater
Weed eater string replacement cartridge
Weed eater oil filter
Weed eater air filter
Spark plug
Screwdriver
Electrical outlet
What You'll Need
Weed eater
Weed eater string replacement cartridge
Weed eater oil filter
Weed eater air filter
Spark plug
Screwdriver
Electrical outlet

A weed eater is one of the simplest powered garden tools to use. Like all technology, however, there will be times when it doesn't work properly. Here are a few things to consider when diagnosing what's wrong with your tool and getting it back in working order.

Weed Eater Not Starting

Check the obvious first. Make sure the switch is in the ON position. For an electric unit, make sure it's properly plugged in to a working outlet. For a gas unit, make sure there's enough fuel in the tank.

If you have a gas weed eater, check to see you haven't flooded it with too much fuel. This happens if you've overcranked the weed eater or if you've poured too much fuel into the engine. If the problem is too much fuel, syphon out some. If the problem is overcranking, you'll need to let the eater sit for about 15 minutes so that the fuel can settle.

Next, check to make sure the fuel filter isn't clogged. This could prevent the fuel from reaching the carburetor. If the filter is dirty, simply replace it. It's always a good idea to have an extra fuel filter on hand for a quick fix. A kinked or split fuel line can also prevent fuel from getting to the carburetor. Check along the line for problems or leaks, and replace it as needed.

A faulty spark plug could also be the the reason why your weed eater isn't starting. Again, this is an easy fix. Take out your old spark plug and bring it to the hardware store to buy a new one. Then just install the new spark plug.

Rough Idling

This is a problem more frequently with gas-powered weed whackers and is usually a sign of a problem that needs to be fixed by an authorized service dealer. Possible causes of an engine not idling properly include low compression, worn crankshaft seals, or a carburetor that requires adjustments. Adjusting the carburetor can be done yourself by tweaking the carburetor screws while the unit is idling. Compression and crankshaft seal problems will need to be fixed by a professional.

Engine Running but Not Cutting Grass

This is usually a sign that the string, the part of the weed eater that does the actual grass cutting, has come out. The easiest way to replace the string is to buy a string replacement cartridge. If you prefer to save yourself a little money, you can restring the weed eater yourself.

To do this, remove the lower part of the head where the string comes out by pushing it in and turning it counterclockwise. Thread the new string through the guides by following the arrows. Make sure you cut the string no shorter than six inches otherwise it won't advance when the weed eater is on. Follow the same steps for the bottom of the head.

Weed Eater Lacks Power

This could be caused by a dirty air filter, damaged spark plug, low compression, carbon build-up on the muffler outlet screen, or idling problems with the carburetor.

An air filter is easy to replace and so is a damaged spark plug. Low compression, carbon build-up on the muffler outlet screen, or idling problems with the carburetor will likely need to be fixed by an authorized service dealer. However, you may be able to do carburetor adjustments yourself if they are minor.

When trying to fix a failing power tool like a weed whacker, always start with the simplest problems first. Obviously a damaged spark plug or clogged filter will not cost a lot to repair like professional service. Checking these parts on a regular basis is also just a good practice, to avoid problems at a later date.