Learning how to drain gas in lawn mower is an essential skill for any homeowner. Draining old gasoline from your lawn mower’s tank and carburetor is a critical step for preparing it for storage. If you leave fuel sitting over the winter, it can turn into a gummy varnish that clogs the delicate parts of your engine. This simple maintenance task can save you from costly repairs and frustrating starting problems next spring.
This guide will walk you through the entire process safely and effectively. We’ll cover everything from the tools you need to the final steps for proper storage. You’ll learn multiple methods to ensure your mower is ready for its long rest.
How To Drain Gas In Lawn Mower
Before you start, it’s crucial to gather the right materials and take safety precautions. Gasoline is highly flammable, so always work in a well-ventilated area, away from any open flames, sparks, or heat sources. It’s best to do this outside on a flat, stable surface.
Tools And Materials You Will Need
- A pair of safety glasses and work gloves
- A socket wrench or adjustable wrench
- A flat-head screwdriver
- A clean fuel container approved for gasoline
- A length of clear plastic tubing (about 3 feet)
- A small pan or bowl to catch drips
- Clean rags or paper towels
- Fuel stabilizer (optional, for later steps)
Safety Precautions Before You Begin
Always let the engine cool completely before you start any work. Disconnect the spark plug wire to prevent any accidental starts. This is a non-negotiable safety step. Have a fire extinguisher nearby just in case, and avoid creating sparks with your tools.
Step 1: Prepare Your Work Area
Move your lawn mower to a flat, open area like a driveway or garage with the door open. Place all your tools and containers within easy reach. Put down some cardboard or an old towel to protect the surface from any fuel spills.
Step 2: Drain The Fuel Tank
There are two primary methods for draining the gas tank: siphoning and using the fuel line. The best method depends on your mower’s design.
Method A: Siphoning The Gasoline
This is the most common and straightforward method, especially for mowers without a convenient fuel valve.
- Locate the gas cap on top of the fuel tank and remove it.
- Insert one end of your clear plastic tubing deep into the tank until it touches the bottom.
- Place the other end into your approved fuel container, which should be on the ground lower than the mower’s tank.
- Suck gently on the end of the tube (or use a siphon pump) to start the flow of gasoline. Once the fuel begins flowing, quickly direct the tube into the container.
- Allow the tank to empty completely. Tilt the mower slightly to get the last bit of fuel from the corners of the tank.
Method B: Using The Fuel Line
Many lawn mowers have a fuel line that runs from the tank to the carburetor. This can provide a cleaner drainage point.
- Locate the fuel line. It’s a small rubber hose connecting the bottom of the gas tank to the carburetor.
- Place your drip pan beneath the connection point at the carburetor.
- Using a clamp or your fingers, pinch the fuel line to stop flow. Then, carefully disconnect the hose from the carburetor end.
- Direct the open fuel line into your container and release the pinch. The gasoline should drain out freely.
- If the flow is slow, you may need to gently blow into the gas tank vent (with the cap off) to create pressure and push the fuel out.
What To Do With The Old Gasoline
Never pour old gasoline down a drain, onto the ground, or into regular trash. It is hazardous waste and must be disposed of properly. Check with your local recycling center, auto parts store, or hazardous waste facility for drop-off locations. They often accept old fuel for safe disposal or recycling.
Draining The Carburetor And Fuel Lines
Simply emptying the tank isn’t always enough. Gasoline left in the carburetor bowl and fuel lines will still evaporate and leave gummy residues. To fully protect your engine, you should drain these components as well.
Locating The Carburetor Drain Screw
The carburetor is usually a small, metal box located near the air filter. On the bottom of the carburetor’s float bowl, you will often find a small drain screw or nut. Consult your owner’s manual for its exact location on your model, as designs vary.
Step 1: Access The Carburetor
You may need to remove the air filter cover and the filter itself to get a clear view of the carburetor. Use your screwdriver for this. Keep track of any screws you remove.
Step 2: Drain The Float Bowl
- Place your drip pan directly underneath the carburetor drain screw.
- Using the correct size wrench or screwdriver, slowly turn the drain screw counter-clockwise. Do not remove it completely; just loosen it enough for fuel to trickle out.
- Allow all the gasoline in the bowl to drain into the pan. This may only be a few tablespoons.
- Once it stops dripping, carefully retighten the drain screw. Do not overtighten, as you could strip the threads.
Step 3: Run The Engine Dry (Optional But Effective)
After draining the tank and carburetor, there may be a small amount of fuel left in the lines. To clear it, you can try to start the engine and let it run until it stalls. Reconnect the spark plug wire first. This will burn off the remaining fuel in the system. Do not do this for an extended period, just until the engine naturally stops.
Alternative: Using Fuel Stabilizer
If you prefer not to drain the gas, or if you have a mower you use intermittently during the off-season, using a fuel stabilizer is a great alternative. Stabilizer prevents the gasoline from breaking down and forming gums and varnishes for up to 24 months.
How To Stabilize Fuel For Storage
- Add the correct amount of fuel stabilizer (like Sta-Bil) to a nearly full gas tank. Always follow the instructions on the bottle.
- Run the engine for 5-10 minutes. This circulates the treated fuel throughout the entire fuel system, including the carburetor and fuel lines.
- After running, you can then store the mower with the treated fuel in the tank. This keeps the internal parts coated and protected from corrosion.
This method is often easier for many people and is highly effective for seasonal storage. However, for very old gas (over a year), draining is still the best option.
Final Steps For Proper Lawn Mower Storage
Once the fuel system is prepared, take a few extra steps to ensure your mower is in top shape when you need it again.
Change The Engine Oil
Old oil contains contaminants that can damage engine components over time. It’s best to change the oil at the end of the season, not the beginning. This way, fresh oil sits in the engine all winter, preventing corrosion.
Clean The Mower Deck And Blades
Use a putty knife or brush to remove all caked-on grass clippings from under the mower deck. This prevents moisture retention and corrosion. You can also sharpen the mower blades now so it’s ready for the first cut.
Remove And Charge The Battery
For riding mowers with a battery, disconnect the terminals and remove the battery. Store it in a cool, dry place and put it on a maintainer charger over the winter to prevent it from going dead.
Store In A Dry, Protected Place
Finally, cover your mower with a breathable cover and store it in a dry place like a shed or garage. This protects it from dust and moisture. Avoid plastic tarps that can trap condensation.
Frequently Asked Questions
How Often Should I Drain The Gas From My Lawn Mower?
You should drain or stabilize the gas in your lawn mower anytime it will be sitting unused for more than 30 days. For seasonal storage over winter, it is absolutely essential.
Can I Leave Gas In My Lawn Mower Over Winter?
It is not recommended to leave untreated gasoline in your lawn mower over winter. The ethanol in modern gas attracts moisture and separates, leading to corrosion and clogged carburetor jets. Always either drain it or use a stabilizer.
What Is The Easiest Way To Drain A Lawn Mower Gas Tank?
The easiest method for most homeowners is using a simple hand siphon pump with a tube. It requires minimal tools and no disassembly of fuel lines. It’s a quick and mess-free way to transfer the old fuel to a disposal container.
Why Won’T My Lawn Mower Start After Storage?
The most common reason is old, degraded gasoline clogging the carburetor. The fuel evaporates and leaves a sticky residue that blocks the tiny passages. This is precisely why learning to drain the gas properly is so important. Other reasons include a dirty air filter, old spark plug, or a dead battery.
Is It Better To Drain Gas Or Use Stabilizer?
Both methods are effective. Draining is a surefire way to remove the problem fuel entirely. Using a stabilizer is more convenient and also protects the internal metal parts from rust. For long-term storage of a year or more, draining is generally the safer choice. For shorter off-seasons, a quality stabilizer works perfectly.
By following these steps, you can confidently prepare your lawn mower for storage. Taking the time to learn how to drain gas in lawn mower will extend the life of your equipment and ensure it starts easily when the grass begins to grow again. Regular maintenance like this saves you time, money, and frustration in the long run. Remember to always prioritize safety and proper disposal of materials.