You can get your weed eater, weed whacker, or string trimmer up and running again by following these instructions.
What Should I Do If My Gas Weed Eater Isn’t Starting? Try This
The likelihood is that your string trimmer, weed eater, or weed whacker will not start at some point. When there’s work to be done, there are few things more frustrating than destroying your shoulder trying to get a gas weed eater to start.
Many DIYers can troubleshoot and fix a broken gas weed-eater with a few simple tools and some basic knowledge because the engines on these machines are pretty simple.
When a Gas Weed Eater Won't Start, Here Are Some Troubleshooting Tips
1) Check The Gasoline in your weed eater
Gasoline can break down in as little as 30 days, especially the gasoline we use today, which has ethanol gas it.
When the season is over, some people put their string trimmers in the garage without stabilizing the gas. Oxygen has all winter to break down and ruin the gas, so in the spring your trimmer won’t work.
If this is the case with your trimmer, empty the old gas out of the tank and fill it with new gas.

If your weed eater won’t turn on, try taking out the air filter and spraying it with carburetor cleaner.
2) Clean The Carburetor in your weed eater
When gas breaks down, varnish, gums, and other particles can build up inside the carburetor and block the tiny fuel passages. This keeps fuel from getting to the combustion chamber and igniting, leaving you with a trimmer that won’t start.
Take out the air filter and spray the intake with carburetor cleaner. Let it sit for a few minutes to help the varnish loosen and break down. Try starting the trimmer again after you’ve changed the filter.
If this doesn’t fix the problem, you might want to take apart the carburetor to clean it better.
Be careful, though. Once you take apart a carburetor, you can’t put it back together again. Even on a fairly simple string-trimmer carburetor, it can be hard to figure out how the small gaskets, screws, and needle valves go back together. Take pictures of the process with your phone to help you put it back together. With carburetor cleaner, clean all of the holes and passages.
If you don’t want to take the carb apart, go to a service dealer.

To fix a gas trimmer that won’t start, take out the spark plug and clean the electrodes with light sandpaper.
3) Clean/Replace Spark Plug in your weed eater
If a low-quality oil is used in a two-stroke engine, oil deposits and carbon can clog the spark plug. If there are deposits on the electrode, the spark plug won’t work right, which can hurt the engine’s performance or stop it from running at all.
Plugs are cheap, so if yours is clogged, just buy a new one. If you don’t have a new plug, use light-duty sandpaper to clean the deposits off the electrode and check the gap. Check the owner’s manual to find out how big the gap should be.
If you know the spark plug is good but the engine still won’t start, the coil is probably to blame and needs to be replaced.
Cleaning the air filter on a weed-eater that won’t start

Move the compressed air from the inside of the air filter to the outside to clear out any dirt that might be blocking the airflow.
4) Clean/Replace Air Filter in your weed eater
If the air filter is clogged, the engine doesn’t get enough air to work right.
Before you take out the air filter, use a brush to remove any loose dirt from around the cover and filter element. Tap rigid filters on a tabletop or the palm of your hand to get rid of any dirt or debris that might be stuck in them. Also works well is compressed air. Make sure to let air flow through the filter from the inside so that debris doesn’t get stuck deeper in the filter.
Don’t wash paper filters because it can ruin their tiny structure. Foam filters, on the other hand, are easy to clean. All you need is a mild detergent and warm water.
As with the spark plug, though, it is often best to replace the filter, especially if it is very dirty.

If deposits build up on the spark arrestor screen, they can cut off enough airflow to stop the trimmer from starting.
5) Clean The Spark-Arrestor Screen in your weed eater
A small screen covers the exhaust outlet on many trimmers. This keeps sparks from coming out of the muffler and starting a fire.
As with dirty plugs, too much oil in the gas, bad oil, or running the engine at low speeds for a long time can cause carbon deposits to clog the screen. This stops the flow of exhaust gas, which makes the engine lose power. In the worst cases, heavy deposits can block enough airflow to make it so that the weed eater won’t start.
To fix the problem, take out the spark arrestor screen and spray it with a heavy-duty cleaner, like AMSOIL Power Foam®, to soften the deposits. Then, use an abrasive pad to clean the screen. Put the screen back in place and test the trimmer.
If there is too much carbon on the screen, you should throw it away and get a new one.
