What Causes A Weed Eater To Smoke: (5 Reasons)

What Causes A Weed Eater To Smoke

If your weed eater is smoking or overheating, you need to stop using it. Then, you need to find out what causes a weed eater to smoke so you can get it fixed right away.

A weed eater that is overheating or smoking can be a sign of a serious problem. The most common causes for a weed eater to smoke is the wrong mixture of oil and gas, a dirty muffler, a dirty carburetor, leaking gas or oil, or poor combustion.

Without repair, you could end up damaging your weed eater. It is important to understand what can cause a weed eater to smoke and how to fix it. There are different reasons that can cause smoke and we want to help you identify the problem be it the fuel, oil, engine, or muffler.

In many cases, the cause of smoke from your weed eater can be benign, but there are cases where it can be more serious. If a serious problem is left ignored you could damage your weed eater and even cause injury. 

We are here to help you identify the possible causes of smoke, so you can get your weed eater back to keeping your yard weed free

Should A Weed Eater Smoke

A weed eater runs on a combination of oil and gas and you need the right combination for it to run well. If this mixture is off, parts of the weed trimmer can malfunction or get damaged and this can cause overheating and smoking. You do not want to be using a weed eater that smokes.

If your weed eater starts to smoke, you need to turn it off right away. Continuing to use it can damage it and can cause injury. Too little oil will cause the weed eater to overheat and too much can cause it to smoke. 

You need to have the right mixture of oil and gas, so this is the first thing to examine if you notice smoke.

Why Does My Weed Eater Smoke

The most common cause for a weed eater to smoke is the wrong mixture of oil and gas. Weed eaters do not have separate compartments for gas and oil, so you have to create the right mixture. This will keep the engine lubricated and running well. Too much oil causes the engine to smoke.

The Gas/Oil Mixture

The correct mixture will depend on the model of weed eater you have. Some require a 32:1, 40:1, or 50:1 fuel-to-oil ratio. 

Remember that the oil and gas will separate over time, so this may need to be mixed up occasionally. You should also shake the mixture thoroughly every time you change or add oil and fuel.

For fuel, make sure you are using regular unleaded and not diesel fuel. Do not use any fuels that have more than 10 percent alcohol as these do not work well for weed eater engines.

In addition to the wrong amount of gas or oil, there are other possible causes for a weed eater to be smoking.

Dirty Muffler

The fuel in the engine gets ignited which creates exhaust fumes. These fumes need to be pumped out to prevent overheating. 

Fumes travel from the exhaust port to the muffler and after a few years, carbon layers can develop and clog the muffler. 

These carbon layers can become ignited by new exhaust fumes and this will cause smoking. To prevent this, make sure you clean the muffler with a tube brush and rag after every 30 hours of use.

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Dirty Carburetor

Fuel that passes through the carburetor over time can leave impurities behind. These clog the carburetor forcing gas to flow through other channels. 

Gas can then hit the engine, burn and cause smoke. To unclog the carburetor, you will need to have a professional mechanic service and clean it. Once clean, the smoking will cease.

Leaking Gas/Oil

The gas in a weed eater flows from the gas tank to the carburetor and then to the cylinder and back to the tank. A faulty gas hose can cause leaking and if this gas hits the heated engine, it can cause smoking. 

If you replace the fuel lines and hoses every season you can prevent this. When you add a new hose make sure you use a press fluid to make sure the lines stick to the carburetor ports.

Poor Combustion

The engine of the weed eater cannot run as needed if the fuel-air mixture is too rich. When this happens in the combustion chamber, some fuel can burn incompletely which produces a thick, black smoke. 

This typically happens if you forget to turn off the choke after the engine starts. It also happens if the fuel is too old, so be sure you are adding new fuel regularly.

White Smoke From Trimmer

Smoke from a weed eater is typically either going to be white or black. Black smoke will only come from a gas-powered engine, but white smoke can come from both gas and electric weed eaters. 

White smoke is caused when there is too much friction in the motor. This can happen as a result of wear and tear to the motor brushes or because there is not enough lubrication.

Too much friction can cause serious damage to the motor and you will need to have it replaced. So, it is important to pay attention when you see white smoke. 

You may have to replace the motor brushes if lubrication does not fix the issue. You can avoid this by keeping the motor properly lubricated regularly and by not using the weed eater if it is smoking.

With cordless weed eaters, there can be an additional cause for white smoke. There may be a connection between the motor and the battery. Water damage and wiring can cause this connection to degrade and the engine can short circuit.

The battery ends up sending excess electric power to the motor directly which can burn the casing material around the motor. 

White smoke is produced and because the material will contain plastics, it can be dangerous to inhale. At this point, you can replace the connections or get a new weed eater.

Weed Eater Blowing Blue Smoke

Blue smoke coming from your weed eater is typically a sign that there is too much oil and the fuel ratio is too rich. 

This can be easily fixed but you need to turn the weed eater off immediately to prevent serious damage. Simply, replace the fuel with a correct ratio of gas and oil. The right amount of oil is important as it keeps the piston lubricated. 

Too much oil does not cause as much damage as having too little, but you still want to maintain the correct ratio to take the best care of your weed eater.

Weed Eater Overheating

Your weed eater required fuel to burn in order to create power. Except for battery or electric-powered machines. Gas powered weed eaters are the ones most likely to smoke but all types can overheat. 

If the engine is unable to release the gases created, then it can overheat. This happens if the engine vents become blocked in any way, such as carbon layer buildup. There are several things you can do to help prevent your weed eater engine from overheating.

  • Clean Air Passages: The air passages of a weed eater regulate air flow. There is an air filter to bring in cool, clean air and a muffler to push out hot gases from the engine. These passages can both get blocked or dirty which affects incoming and outgoing air. Remove the air filter and wash with soapy water or clean the muffler with a wire brush, depending on which area is clogged.
  • Check The Fuel: Because the gas and oil can separate over time, this can cause the engine to overheat. To make sure the engine gets the oil it needs, regularly shake the oil and gas to maintain a good mix. As mentioned previously, you also need to make sure the fuel to oil ratio is correct.

Why Is My Electric Weed Eater Smoking

An electric weed eater will likely be smoking as a result worn out motor brushes. You will need to remove the brushes to check their length. 

If they have become too short, they will need to be replaced. Smoke from an electric weed eater can also indicate that the motor needs more lubrication. Regular cleaning and lubrication can fix this.

There are also electrical problems that can cause your electric weed eater to smoke. If the weed eater voltage does not match the voltage of the outlet, you can overheat the engine which causes smoking. 

There may also be electrical shorts in the wires, causing overheating, and the plastic compartment around the engine begins to burn and smoke. 

You need to check all wires and circuits before continuing to use the weed eater. And change the outlet you are using if necessary, too.

Why Is My Ryobi Weed Eater Smoking

Smoke from a Ryobi weed eater likely means you need to change the oil levels. Additionally, you may need to also check the valves which may be faulty. 

To do this, remove the Torx head screw which keeps the plastic cover in place. Then remove the screw that keeps the rocker cover on.

If you notice oil in the cylinder head, then drain it out. You will need to replace the faulty valves to prevent this from happening again. This oil accumulation can also happen if you store the weed eater in a vertical position. 

It needs to be horizontal and level to ensure the oil does not move out of its chamber, where it can burn and cause smoke.

Why Is My Husqvarna Weed Eater Smoking

The carburetor may need to be adjusted on your Husqvarna weed eater, if you notice smoke. Loosen the gas cap to look at the cap vent to see if it is plugged. 

There will be a fuel filter that you can remove. If this is plugged, it could be the cause for your smoke, and it needs to be cleaned. 

Filters can be cleaned by washing in soapy water. If this is not plugged, you may need to remove the muffler to clean the spark arrestor screen.

Craftsman Weed Wacker Smoking

Hanging the Craftsman weed eater by its head can cause internal problems that cause it to smoke when used. 

Oil flows into the cover and once the weed eater is turned right side up, the oil flows back through the cover and into the carburetor. 

If you start the engine before all the oil has had a chance to drain away from the engine, it can get sucked into the air filter.

This will cause the plugs to clog which can cause smoke. To avoid this, make sure you hang or store the weed eater properly by keeping the engine facing upwards. 

Additionally, you can also give the oil time to flow back to its crank shaft before starting the weed eater.

Troy Bilt Weed Eater Blowing White Smoke

White smoke from a Troy Bilt weed eater can be because of a blocked air filter or because the muffler is not working. Check the muffler first to see if it runs better without it. 

If it does, then you need to burn the carbon residue from the muffler. Then, clean the muffler port and replace. This should clear up the smoke issues. If not, try removing and cleaning the air filter using soapy water.

Stihl Weed Eater Overheating

Operating a Stihl weed eater improperly is the usual cause for smoke and overheating. It can also be caused by overuse of the choke or carbon deposits on the motor and spark plugs. To make sure you are not overusing the choke, there are a few tips to remember.

  • Once the weed eater is going, move the choke in the opposite direction, all the way

If you are overusing the choke or have an incorrect gas-to-oil ratio, carbon deposits can collect on the spark arrestor screen and block air flow. 

You need to clean this screen regularly in order to prevent this. Check this screen any time that you notice smoke and clean if it is dirty.

4 Cycle Weed Eater Smoking

If your 4 cycle weed eater is smoking, chances are there is too much oil. Weed eaters need to have a specific fuel to oil ratio in order to function efficiently. 

Too much oil causes the engine to smoke. Follow the instruction manual for your specific model to make sure you keep the fuel and oil amounts accurate. You also need to make sure they are combined and shaken well.

Helpful Tips To Know What To Do If Your Weed Eater Smokes

There are many different types of weed eaters on the market, but in general any weed eater that is smoking needs attention. An electric weed eater may have a short circuit, or a gas-powered one can have several different issues. 

Some additional tips to remember if you notice smoke from your weed eater are:

  • Turn it off right away
  • Check oil and fuel mixture first as this is the most common problem
  • For electric weed eaters, make sure it is unplugged before inspecting the motor
  • Confer with the manual to identify where parts are located and cleaning instructions
  • Consider itching out to a professional if you need help

Final Thoughts

A weed eater is an essential part of any yard maintenance routine. The last thing you want to see is smoke coming from the weed eater. No matter which brand and style you have, that is not a good sign. 

Ignoring the smoke can lead to more serious damage. Instead of having to replace the weed eater, learn what causes a weed eater to smoke. 

With our guide, you can identify the problem and most likely can take care of it yourself quickly. The only smoke you should be seeing this season, should be coming from your barbecue.

Drew Thomas

My name is Drew Thomas and I’m the creator of Fun In the Yard, your one stop site for all your outdoor games, sports, party activities, outdoor gear, and lawn & gardening tips.

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