Stale fuel is a leading cause of lawn mower problems, making proper gasoline drainage an important seasonal task. Knowing how to drain gasoline from lawn mower is a key skill for any homeowner. It prevents starting issues, protects your engine, and saves you money on costly repairs. This guide will walk you through the safest and most effective methods.
Gasoline begins to degrade in as little as 30 days. Over time, it forms varnish and gum that can clog your mower’s carburetor and fuel lines. Draining the tank before storage, or when you suspect bad gas, is the best solution. The process is straightforward with the right tools and a bit of caution.
How To Drain Gasoline From Lawn Mower
This section covers the primary method for draining fuel from your mower’s tank. Always work in a well-ventilated area, away from sparks or open flames. Have a proper fuel container ready for the old gasoline—never use a milk jug or glass jar.
Tools And Materials You Will Need
- A certified gasoline safety can or container
- Protective gloves and safety glasses
- A length of clear plastic tubing (1/4- to 3/8-inch diameter)
- A flat-head screwdriver or a socket set
- A clean rag or shop towels
- A funnel (optional, but helpful)
- A pair of pliers (for some models)
Step-By-Step Drainage Procedure
Step 1: Prepare Your Workspace
Move your lawn mower to a flat, level surface outdoors. Ensure the engine is completely cool before you begin any work. Running or hot engines pose a serious fire risk. Gather all your tools and place your empty fuel container on the ground nearby.
Step 2: Locate The Fuel Shutoff Valve
Many lawn mowers have a small fuel valve on the fuel line between the tank and the carburetor. This valve is usually located underneath or near the fuel tank. If your mower has one, turn it to the “Off” position to stop fuel flow. Not all models include this valve, so don’t worry if you can’t find it.
Step 3: Disconnect The Spark Plug
For absolute safety, always disconnect the spark plug wire. Pull the boot off the plug itself. This prevents any accidental starting while you are working on the fuel system. It’s a simple step that should never be skipped.
Step 4: Drain The Fuel Tank Via The Fuel Line
This is the most common and cleanest method. First, locate the fuel line that runs from the gas tank to the carburetor. It’s a small rubber or plastic hose. Use pliers to loosen the clamp securing it to the carburetor, and gently pull the hose off.
- Place your empty fuel container on the ground.
- Insert one end of your clear plastic tubing onto the carburetor end of the fuel line.
- Place the other end of the tubing into your fuel container.
- If your mower has a fuel valve, turn it to the “On” position. If not, the fuel should begin to siphon out immediately.
You may need to gently blow into the fuel tank’s vent to start the siphon if gravity alone isn’t enough. Let the tank drain completely.
Step 5: Drain The Carburetor Bowl
Even after draining the tank, fuel remains in the carburetor bowl. To drain it, look for a small bolt or nut at the very bottom of the carburetor. This is the bowl drain plug. Place your container underneath and carefully loosen the plug with a wrench. Let all fuel drip out, then retighten the plug securely.
Step 6: Run The Engine Dry (Optional But Recommended)
After draining, you can reconnect the fuel line to the carburetor. Reconnect the spark plug wire. Start the mower and let it run until it stalls from the remaining fuel in the lines. This helps clear the carburetor’s internal passages. It’s a good final step for winterization.
Alternative Method: Using A Siphon Pump
If disconnecting fuel lines seems daunting, a manual siphon pump is a great alternative. These are inexpensive and available at any auto parts store. Simply insert the pump’s tube into the mower’s fuel tank, pump the primer bulb a few times, and direct the flow into your container. It’s mess-free and effective, though you may not get every last drop from the carburetor.
Safety Precautions When Handling Gasoline
Gasoline is highly flammable and its vapors are explosive. Your safety is the most important part of this task. Never take shortcuts when dealing with fuel.
Essential Safety Gear
- Wear safety glasses to protect your eyes from splashes.
- Use chemical-resistant gloves to keep gasoline off your skin.
- Work in a well-ventilated area to avoid inhaling fumes.
Critical Safety Rules
- Never drain gasoline indoors, in a garage, or near a water heater.
- Do not smoke or have any ignition sources nearby.
- Always use a container designed and approved for gasoline storage.
- Clean up any spills immediately with rags, and dispose of them properly outdoors.
- Store leftover gasoline in a labeled, approved can, out of reach of children.
What To Do With The Drained Gasoline
You should never pour old gasoline down a drain, onto the ground, or into the trash. This is illegal and harmful to the environment. Proper disposal is easy.
Options For Disposal Or Reuse
- Check with your local waste management authority or auto repair shop. Many communities have hazardous waste collection days where you can drop off old fuel.
- If the gasoline is relatively fresh (less than a month old) and uncontaminated, you can mix it with fresh gas in your car’s tank. Use a ratio of one part old gas to at least four parts new gas. Your car’s larger engine can typically handle the slight dilution.
- Never use old, stale gasoline in any small engine. It will cause the same problems you are trying to avoid.
When Should You Drain Your Lawn Mower’s Gas?
Timing is important. Draining your mower’s fuel at the right moments prevents most fuel-related issues.
Before Long-Term Storage (Winterization)
This is the most common reason. If you won’t be using your mower for more than 30 days, especially over winter, you should either drain the tank completely or use a fuel stabilizer. Draining is often the more reliable method to ensure no residue is left behind.
After Using Ethanol-Blended Fuel
Most gasoline contains ethanol, which attracts moisture from the air. This moisture can separate from the fuel inside your tank, leading to corrosion and engine damage. If you use regular pump gas, consider draining the mower if it will sit for an extended period.
When The Mower Won’t Start
If your mower has been sitting and now refuses to start, old gas is the prime suspect. Draining the old fuel and replacing it with fresh gasoline is the first troubleshooting step you should take. It often solves the problem immediately.
Preventative Tips To Avoid Frequent Draining
While draining is sometimes necessary, you can reduce how often you need to do it with a few smart habits.
Use A Fuel Stabilizer
For seasonal storage up to 12 months, add a fuel stabilizer to a full tank of fresh gas. Run the engine for a few minutes to circulate the treated fuel through the carburetor. This keeps the gasoline from breaking down as quickly.
Consider Ethanol-Free Fuel
Many small-engine manufacturers recommend using ethanol-free gasoline (often sold as “recreational fuel”). It is more stable and less prone to absorbing moisture. It can be found at many hardware stores, marinas, and some gas stations.
Run The Mower Regularly
If possible, try to run your mower for a few minutes every month during the off-season. This keeps the fuel moving and the internal parts lubricated. It’s a simple way to maintain the system.
Frequently Asked Questions
How Do You Get Gas Out Of A Lawn Mower Without A Siphon?
You can drain the gas by disconnecting the fuel line from the carburetor, as described in the main steps. Alternatively, you can carefully tip the mower on its side (with the air filter and carburetor facing up) and pour the gas out through the filler neck into a container. Be extreamly careful to avoid spills.
Is It Better To Drain Gas Or Use A Stabilizer?
For very long storage (over 6 months), draining the tank and carburetor is the most thorough and reliable method. For shorter off-season periods (1-6 months), using a high-quality fuel stabilizer in a full tank is a convenient and effective alternative. Both are good practices.
Can Old Gas Ruin A Lawn Mower Engine?
Yes, stale gasoline is a primary cause of lawn mower failure. As it degrades, it forms gummy deposits that clog the tiny jets and passages in the carburetor. This prevents the engine from getting the correct fuel-air mixture, leading to poor performance or a complete failure to start. In severe cases, it can require a costly carburetor rebuild or replacement.
How Long Does Gas Last In A Lawn Mower?
Fresh, untreated gasoline begins to oxidize and go bad in about 30 days. After 60 days, it can cause starting problems. After 90 days, it’s often too stale to use reliably. Using a stabilizer can extend this life to 12-24 months. Always try to use fuel that is less than a month old for best results.
What Is The Easiest Way To Drain A Lawn Mower Fuel Tank?
The easiest method for most people is to use a manual hand siphon pump. It requires no disassembly, is relatively mess-free, and is very effective at removing most of the fuel from the tank. It’s a worthwhile investment if you maintain several small engines.
Learning how to drain gasoline from your lawn mower is an essential piece of maintenance. It protects your investment and ensures your mower starts easily when you need it. By following these steps and safety guidelines, you can perform this task confidently. Regular maintenance, including proper fuel management, is the key to a long-lasting and reliable lawn mower. With the old fuel properly disposed of, you can look forward to a trouble-free mowing season.