Why Your Weed Eater Keeps Bogging Down

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Sometimes a weed eater will start only to shut down moments later. Or the machine will not start at all. No matter what weed eater or string trimmer brand you use, this can happen every now and then. This troubleshooting guide shows you exactly what to do.

The most common reasons why weed eaters keep shutting down are a clogged carburetor, dirty air filter or faulty spark plug. The engine will also die out if the fuel mixture is wrong or the fuel is too old.

Check the Fuel

The first place to look is the fuel. There are several problems related to this that might cause your weed eater to bog down. They are:

  • Old fuel
  • Wrong fuel mix
  • Not enough fuel
  • Too much fuel
  • Damaged fuel filter
  • Broken fuel line

How to Fix. There are different solutions for these fuel issues, but they are easy enough.

Remove old fuel. Turn the weed eater off and drain the fuel tank. Hose the tank interior with hot water. Add detergent to the water or better yet, use Star Brite to clean the tank.

If the tank is large enough, use a brush to remove stuck debris. Swish the liquid so it gets all the debris.

Dispose of the water properly and use a clean cloth to wipe the tank interior.

Check the tank for signs of damage. Replace it if there are cracks. If it is only dirty and gummed up, proceed to the next steps.

You can let the fuel tank dry naturally or use compressed air to speed it up. Add water remover or antifreeze to get rid of the moisture. Let the fuel tank dry for at least half an hour.

Wrong fuel mix. You have to discard the fuel and pour in a new mixture. Weed eaters run on a 40:1 or 50:1 ratio, so check your manual for the proper ratio. Clean the tank first before adding the new mix. If you are using a Black + Decker electric string trimmer this will not be necessary.

Too much or too little fuel. If there is too little fuel, add some more. If there is too much, turn the weed eater on and let it run the excess fuel off.

Damaged fuel line and filter. You will often find the fuel line inside the tank, but check your manual to be sure. Remove the fuel line and examine it along with the filter. Replace both if there is damage.

Defective Spark Plug

if the spark plug is dirty or damaged, the engine will not start. You will know it is a spark plug issue if you added fuel but the weed eater still refuses to run.

A blown spark plug can cause widespread problems. It can affect the trimmer head and prevent the line feed from working.

Related. Weed eater line not feeding: causes and solutions

How to Fix. Remove the boot from the spark plug. Check the plug for signs of burnout or dirt buildup. If the tip is damaged, replace it. You can clean a spark plug but if it is already old, get a replacement.

If the spark plug is new, clean it and try again. If that does not work, it has already been damaged and must be disposed of. You can find replacement spark plugs for your weed eater online, just look for the make and model.

Blown Gasket

String trimmer gaskets function as sealants to prevent fuel and air from getting into areas they are not supposed to. A blown gasket for instance, could lead to increase of air in the air/fuel mixture.

This can have serious repercussions in terms of performance. If there is too much air in the mix, the engine might bog down. The same thing will happen with other 2-stroke engines like lawn mowers and hedge trimmers.

How to Fix. The only option is to replace the gasket. You have to take the fuel filter and fuel line out first before you can see the gasket. If there are cracks or tears, replace it. Gaskets cannot be reused so you have to replace them.

You can find a replacement gasket – as well as other parts – for your string trimmer online. The best place to look is the manufacturer website. Just enter the make and model number of your weed eater and you should be able to find a suitable gasket. This also applies to other components.

Blocked Air Filter

Air filters do two things: keep dirt out and let fresh air in. If there is a blown gasket however, too much air will get into the trimmer. This can cause the engine to stall and refuse to start.

Too much can cause problems and so will excessive dirt. Air filters accumulate grime and if they get too clogged, can no longer function. Thee dirt could scatter throughout the engine and prevent air from getting in.

How to Fix. Remove the air filter and brush the debris off. Use water if there is a lot of stuck dirt. You might need to use soap too. Wait for the filter to dry before putting it back.

Replace the filter if it is damaged. The filter might develop tears and get worn out. Just replace these and your trimmer should run fine.

Dirty or Damaged Carburetor

The fuel lines connect to the carburetor, so any clogging or damage here affects the whole engine. When checking for carburetor issues, there are usually two options: cleaning or replacement.

Cleaning. In majority of cases, the carburetor just needs to cleaned up. Use a solvent-based solution or one of the many cleaners available. Once cleaned the unit should be ready for use.

Carburetor rebuild kit. If there is some damage, you will need a rebuild kit. As the name suggests, these kits contain parts that you can use to rebuild the carburetor after cleaning it.

Replace the carburetor. Rebuilding is not for everyone. It can be cumbersome and complicated. That is why some prefer to just buy a new carburetor. It makes things easier and at some point, you have to replace the unit anyway. But if the carburetor is new and just clogged, cleanup will be enough.

Electrical Weed Eater Problems

If your electric weed eater keeps stalling, there is probably an issue with its electronic motor. Here are some common problems and fixes.

Loose power cord. If the power cord is too short, it could come off and lose power. This will cause the weed eater to suddenly stop. Check the cord and make certain it is plugged in. Get an extension cord if it keeps coming loose.

Blown breakers or fuses. This can happen with almost all electrical devices and string trimmers are no exception. Always check the fuses before turning the machine on.

Overloaded motor. Electric weed eaters are not as powerful as gas-operated trimmers. If you use the trimmer for extended periods on large areas, the motor can overload and overheat. At some point the engine is going to shut down.

Weed Eater Maintenance Tips

How you maintain your weed eater makes a huge difference in its performance. With the proper approach you can prolong its life and minimize engine problems.

Clean the trimmer after each use and a more thorough cleaning every week, two weeks or every month. For standard cleaning, remove all clogging in the trimmer head. During the more thorough maintenance, clean the filters and check the spark plugs, gaskets etc.

Store the trimmer in your garage or shed. Do not let it get rained or snowed on. Always turn the trimmer off before storage. If you will be storing it for winter, empty the fuel tank or put antifreeze to prevent the fuel from turning gummy.

For electric weed eaters, check the cord regularly for signs of damage. Replace immediately if it is worn out. Shut the tool immediately if the motor gets too hot or smokes.

Only use weed eaters as indicated in the operating manual. If you want to use it for other yard work, look or attachments that can expand its functions.