Symptoms of Bad Gas in a Lawn Mower

Storing a lawn mower for a long time unused turns gasoline into bad gas. If you have to keep the mower away for an offseason, you have to take the proper steps for your lawn mower to get back in shape.

The first thing is checking the gasoline – particularly when you didn’t use a fuel stabilizer.

Gas has a short shelf life of about three months without treatment.

So, without a fuel stabilizer, the lawn mower will splutter or not start. Before you panic or call your mechanic, do a quick checkup of bad gas symptoms. Bad gas is among the prevalent problems to expect.

This article will explore various topics on bad gas in lawn mowers. We have also highlighted some insights on what you should do after the lawn mower’s gas goes bad.

Let’s get started:

Common Symptoms of Bad Gas in Lawn Mower

Most lawn owner users will not check the condition of their lawn mower’s gas after the offseason. Using bad gas will present as one of the problems the lawn mower experiences.

If you experience these problems with your lawn mower, the gas could be responsible after it expired:

  • Thumping noise from the engine
  • The lawn mower doesn’t start
  • Mower experiences difficulty while starting

Before taking the mower for checkup or maintenance, ensure you have checked gasoline.

Ensure the gas is still in good condition or change to fresh gas. That may cost you less amount than taking a trip to your mechanic.

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How to Test Bad Gas in a Lawn Mower

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If you suspect the problem with your mower is the gas, consider these two tests below:

How to Test Bad Gas in a Lawn Mower

1. Gasoline Smell Test

Gasoline usually has a distinctive odor you are familiar with. Therefore, a simple way you can check the condition of the gas is to smell it.

Take the mower outdoor and far from your car. That ensures the smell from gas and oil will not confuse your nose.

The other step is to open the gas cap of your mower and waft the smell towards your nose. The smell determines the condition of the gas; where sour or stale means the gas has gone bad.

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2. Check Appearance of the Gasoline

If you have seen fresh gasoline before, then bad gasoline will look different. Fresh gasoline is clear in color and free of clumping. If your mower is the push type, get a tin pan or something you can use to collect the fuel.

Riding mowers require you to use a siphon pump when removing the fuel. So, when you realize the gas is dark in color or has clumps, that will mean it has turned bad.

You can have fresh gas and use it to compare with the gas in question. The method provides you with a control subject where you can check against your observations.

Also read: How to clean a metal lawn mower gas tank

Why Gasoline Go Bad

There are a few reasons that turn gasoline in your lawn mower bad. First, the main cause will be volatility.

This is the ability that allows gasoline gas to burn. The lighter the chemical, the more it evaporates fast, which leaves incombustible gas to turn gummy. This is the substance you find clogging up in the fuel lines.

When you keep your lawn mower with gas for an extended time, the gas goes bad.

That’s because old gas usually has hydrocarbons and will react with oxygen to form new compounds – due to oxidation. The reaction produces a gum-like substance clogging the fuel filter, carburetor, and gas lines.

Bad gasoline is harmful to carburetors because it is expensive to fix them. Again, they will not run smoothly until you clean inside. It is something that will occur at empty tanks, too, after residues remain in the tank.

The other thing that may make the gas turn bad is temperature fluctuation. When the temperature fluctuates, gasoline condenses, forming water that finds its way into the fuel tanks leading to problems.

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how to tell if gas is bad in lawn mower

Effects of Bad Gasoline in a Lawn Mower

As we mentioned earlier, having a bad gas in your mower clogs up its fuel line. The effect causes the engine not to function correctly. In addition, bad fuel has proved to kill the engine.

Condensation of old gas will form water in the engine, thus forming corrosion and rust.

That will make the engine stop working until you take the lawn mower to a mechanic for proper cleaning. In extreme cases, you will be forced to replace your engine.

Water may also hinder engine lubrication. The right thing is avoiding bad gas, and when in your engine, replace it.

This happens: Adding too much fuel stabilizer

Effects of Bad Gasoline in a Lawn Mower

FAQs on Symptoms of Bad Gas in a Lawn Mower

How will I tell my lawn mower gas is bad?

The smell and appearance of gasoline can help determine the state of your mower’s gas.

Bad lawn mower gas will have a muddier and darker appearance.

The gas will also have a disagreeable or sour odor.

Will bad gas damage my lawn mower’s engine?

Running your lawn mower with bad gas will damage your carburetor, filters, and gas pipes.

This will result from the condensation of old gas-forming water in the engine; water corrodes the fuel tank and stops the engine from working.

How long will gas stay good in my lawn mower?

Generally, gasoline gas will stay fresh depending on its formula. Most formulas degrade within 30 days while treated stay over a year.

You can prevent that by adding a stabilizer or emptying the fuel tank. 

Read: How to dispose of old mower gasoline

Bad gas is among the reasons resulting in the defective functioning of your lawn mowers.

Symptoms of bad gas in a lawn mower should be the first thing you check when the lawn mower doesn’t function properly. This will result from old gas that oxidizes to damage the fuel system.

The proper precaution of the lawn mower is to keep it where it’s not exposed to temperature changes.

If the gas turns bad, drain it and wipe it clean. Ensure at least you change the fuel once in two months for the safety of your lawn mower’s engine.

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  • Ricky

    Hi, I’m Ricky. I’ve been involved in lawn care and landscaping from when I was 15. To be honest, I didn’t like the idea of pushing mowers, collecting grass clippings, and maintaining flowerbeds at the time. But having seem the passion my parents had for gardening and outdoors and the effort they put in maintaining the health and beauty of our landscape, I couldn’t help but not only admire their hard work but also I became a part of it. As someone who loves to spend time with nature’s best, I find myself learning a lot more about gardening and outdoors on a daily basis. Not to mention I love to share the knowledge I’ve gathered over the years with my readers at We Mow Dallas. To be clear, I don’t have a Master’s degree in gardening or anything like that. Everything I’ve learned about gardening, landscaping, and lawn care spring from passion and engagement with my parents. And with a ton of free information out there, plus the ability to run tests and determine what works best for lawn care and landscaping, every day is an opportunity to learn and implement something new. My goal with We Mow Dallas is to teach you exactly how to maintain your lawn and landscape. And since I walk the talk in reality, you shouldn’t hesitate to join me in this wonderful world of landscaping and lawn care. K Beatrice

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