How to Start a Lawn Mower with Old Gas ?

Are you a homeowner worried about starting the lawn mower in freezing weather? While many homeowners assume that if it’s too cold outside, the grass seed won’t take hold or grow, this isn’t always true.

Depending on where you live and what type of grass seed you are using, there might be times when it is too cold even for planting grass seed.

As a mechanic, I want to share a comprehensive and easy-to-follow guide to help you start your lawn mower with old gas and ensure that your machine remains in proper working condition. Please adhere to the safety precautions and use the necessary tools while handling the device.

How to Start Lawn Mower with Old Gas?

Tools Required:

  1. Safety gloves
  2. Goggles
  3. Flathead screwdriver
  4. Wrench
  5. Old rag or cloth
  6. Spark plug wrench
  7. Gas container
  8. Oil container
  9. Funnel
  10. Carburetor cleaner (optional)

Safety Precautions:

  1. Wear safety gloves and goggles while working with the lawn mower to prevent injury.
  2. Detach the spark plug cable before beginning other tasks to avoid accidental ignition. Please make sure the engine is off and completely cooled down.
  3. Work in a well-ventilated area to prevent inhaling any harmful fumes.

Here are some simple steps for the lawnmower old gas starting procedure.

1. Detaching the Spark Plug

  1. Locate your lawn mower’s spark plug. Check the consumer manual if you are unsure about its location.
  2. Using your hands or a wrench, gently remove the spark plug wire from the plug by pulling on the boot.

2. Removing Oil and Old Gas

  1. Use a flathead screwdriver to open the gas cap and place the funnel inside the gas tank.
  2. Place the gas container under the funnel and slowly tip the lawn mower to pour the old gas into the container. Be careful not to spill the old gas on the engine or the ground.
  3. For the oil, locate the oil drain plug according to your lawn mower’s user manual and use a wrench to remove it. Place an oil container under the drain plug to catch the old oil.
  4. Following local regulations, allow all the old oil to drain and properly dispose of it.

3. Cleaning or Replacing the Spark Plug

  1. Check the spark plug for any signs of wear, corrosion, or carbon buildup. If it looks dirty, use an old rag to clean it off. If any of these issues are severe, consider replacing the spark plug.

4. Priming the Engine (if applicable)

  1. Locate the primer bulb of your lawn mower, which is generally a small rubber button near the carburetor.
  2. Press the primer bulb a few times to send fresh fuel to the carburetor.

5. Filling Up With Fresh Gas and Oil

  1. Pour fresh gas into the lawn mower’s gas tank using a funnel, but do not overfill it. Close the gas cap when done.
  2. Refill the oil tank with the recommended type and amount specified by your lawn mower’s manufacturer. Replace the oil drain plug securely.

6. Starting the Engine

  1. Reassemble the spark plug wire to the spark plug.
  2. Start the lawn mower following the standard procedure– pulling the start cord or turning the key.

Regular Maintenance Tips

  1. Drain your lawn mower’s fuel and oil at the end of every mowing season.
  2. Store your mower with an empty gas tank or use a fuel stabilizer during off-season storage.
  3. Clean the carburetor regularly to avoid any problems with poor performance.
  4. Check the spark plug and air filters at least once a year, and clean or replace them if necessary.
  5. Keep your lawn mower in a dry place, away from any combustible materials.

Frequently Asked Question

What to do with old gas in lawnmowers?

There are several options for disposing of old gas from your lawn mower. The best option is to take it to a hazardous waste collection facility, which can safely dispose of the fuel. You can also call your local government to see if any household dangerous waste programs in your area will accept used gasoline for disposal.

Additionally, you can mix the old gas with cat litter or sawdust to absorb the gasoline and dispose of it in a sealed container. Never pour old gas directly onto the ground, as this can be hazardous to people and the environment. If you are unsure how to dispose of your used fuel safely, contact an experienced mechanic for advice.

How often should I replace my lawn mower’s spark plug?

Replacing the spark plug in your lawn mower every season or after 100 hours of use is generally recommended. This will assist in ensuring that your engine starts reliably and runs smoothly. Additionally, check the spark plug for any signs of wear, corrosion, or carbon buildup before each use and clean or replace it if necessary. If you are unsure how to return your lawn mower’s spark plug, consult a qualified mechanic.


I hope you found this guide helpful and enabled you to start your lawn mower even with old gas. Don’t forget to follow the regular maintenance tips so that you can keep up the performance of your machine year after year.

Old gas in lawn mower engines can be dangerous if mishandled, so always take the necessary safety precautions and use the right tools when working with your machine. If you ever feel like something is wrong, consult an experienced mechanic for advice. Happy mowing.

Keep in mind that regular maintenance of your lawnmower is vital to keeping it running correctly and efficiently. It’s essential to regularly inspect your spark plug, air filters, gas and oil tanks, and carburetor to make sure everything is running smoothly. Taking the time to do a bit of maintenance on your lawn mower will ensure that it runs reliably for many years to come.

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