That trusty weed eater is a workhorse, tackling tough weeds and trimming grass along fences and driveways. But over time, you might notice a drop in performance. It starts hard, runs rough, or lacks the power it once had. Before you assume it’s time for a new one, there’s a simple, often overlooked maintenance task that could bring it back to life: checking the exhaust for carbon buildup.
Why Does Carbon Buildup Happen?
Small two-stroke engines, like the one in your weed eater, burn a mixture of gasoline and oil. When the combustion isn’t perfect, or if you’re using an incorrect fuel-to-oil ratio, tiny particles of unburnt fuel and oil can get left behind. Over time, these particles accumulate as a hard, black, crusty deposit on the internal components of the engine, especially in the exhaust port and on the muffler’s spark arrestor screen.
This carbon acts like a clog, restricting the flow of exhaust gases out of the engine. A clogged exhaust means the engine can’t “breathe” properly. The old, burnt gases can’t escape efficiently, which prevents fresh fuel and air from entering the combustion chamber. The result is a sluggish, underpowered, and poorly-running engine.
Symptoms of Carbon Buildup
If you’re experiencing any of these issues, a clogged exhaust is a strong possibility:
- Difficulty starting: The engine is hard to pull over or won’t start at all.
- Lack of power: The weed eater struggles to get up to speed and bogs down under load.
- Rough idling: The engine sputters and stalls when you release the throttle.
- Excessive smoke: While some smoke is normal for a two-stroke engine, a significant increase in dark smoke can be a sign of poor combustion.
- Engine overheating: Restricted exhaust flow can cause the engine to run hotter than usual.
How to Check Your Exhaust for Carbon
Thankfully, checking for carbon buildup is a straightforward process that only requires a few basic tools.
What you’ll need:
- A screwdriver or wrench set
- A wire brush or a small metal scraping tool (like a dental pick or a flat-head screwdriver)
- Protective gloves and safety glasses
Step-by-step guide:
- Ensure the engine is cool: Never work on a hot engine. Let it cool down completely to avoid burns.
- Locate and remove the muffler: The muffler is a small metal canister attached to the side of the engine. Use your screwdriver or wrench to remove the bolts or screws holding it in place.
- Inspect the exhaust port: Once the muffler is off, you’ll see a small opening on the side of the engine block. This is the exhaust port. Look inside for any black, crusty buildup. If you can see a significant amount of carbon restricting the opening, you’ve found your culprit.
- Check the spark arrestor screen: The muffler likely has a small metal screen inside, called a spark arrestor. This screen prevents hot carbon particles from exiting the exhaust and potentially starting a fire. This screen is a common place for carbon to build up. Use your wire brush to clean it or, if it’s completely clogged, you may need to replace it.
- Clean the carbon: Use your wire brush or scraping tool to carefully remove the carbon from the exhaust port and the muffler. Be gentle and avoid gouging the metal. Get as much of the buildup off as you can.
Pro Tips for Preventing Carbon Buildup
Once you’ve cleaned everything up, take some steps to prevent it from happening again:
- Use the correct fuel-to-oil ratio: Always mix your fuel exactly as specified in your weed eater’s owner’s manual. Using too much oil is a common cause of excessive carbon.
- Use high-quality two-stroke oil: Not all oils are created equal. Using a good quality, brand-name two-stroke oil designed for your engine type will ensure cleaner combustion.
- Avoid cheap or old fuel: Old or low-quality gasoline can lead to incomplete combustion. Use fresh fuel and consider using a fuel stabilizer if you’re not going through gas quickly.
- Don’t let the engine idle excessively: Running the engine at a low RPM for long periods can contribute to carbon buildup.
By taking a few minutes to check and clean your weed eater’s exhaust, you can avoid costly repairs and keep your small engine running strong all season long. A little preventative maintenance goes a long way in extending the life of your equipment. Happy trimming!