Ariens Lawn Mower is Leaking Gas (FIXED!)

You smell a strong fuel odor in the air or maybe you see dead spots in the grass from gas leaking onto the lawn. These are signs you have a fuel leak on your Ariens mower.

At times it can be tough finding the place your Ariens mower is leaking, especially if it’s a small leak because gas will evaporate leaving no evidence of a leak.

An Ariens lawn mower can begin leaking gas from the carburetor when the carburetor bowl gasket is bad or the float and float needle are stuck. It can also leak from a cracked or degraded fuel pump, fuel filter, or fuel lines; a faulty fuel shut-off valve; and a bad seal in the fuel cap.

Follow all safety precautions outlined in your owner’s manual to keep you safe while working on your Ariens lawn mower. Because gas fumes can be harmful, make sure you are working on your mower in a well-ventilated area.

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Follow all safety instructions provided in your equipment operator’s manual before diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.

7 Reasons Your Ariens Lawn Mower is Leaking Gas

Carburetor is Leaking Gas

Your carburetor is a good place to start looking for a fuel leak on your Ariens mower. Carburetors get dirty with gummy and crusty buildups that can cause the parts in your carb to not function correctly.

This is the place fuel is stored after it leaves your gas tank. When parts get stuck or the gasket fails, your Ariens will begin leaking gas.

Carburetor bowl gasket failure

The first place to check on your carburetor for a leak is the gasket on the carburetor bowl. It’s common for this gasket to become hard and brittle over time due to the location of the gasket.

It’s located right next to the engine so it heats up when the engine runs and cools down when it is not in use. This constant heating and cooling put a lot of stress on the gasket causing it to lose its sealing ability.

The gasket is located between the carburetor bowl and the carburetor. It kind of looks like a rubber band. If you find a leak in this area, you will have to replace the gasket. This is a pretty simple procedure.

You will need to buy a replacement gasket. To find a good replacement, you’ll need to locate the model and spec number from the engine. Don’t confuse this with the model and serial number of the lawn mower.

Steps to replace the carburetor bowl gasket:

• Shut off the fuel supply using the fuel shut-off valve located at the bottom of your fuel tank. You can also use pinch pliers to crimp the fuel line to stop the flow.
• Wipe the outside of the carburetor so you don’t allow any dirt to enter the carburetor while removing the bowl.
• Have a rag available to collect any fuel remaining in the bowl.
• Remove the screw at the bottom of the carburetor bowl and remove the bowl.
• Remove the old gasket and replace it with the new gasket.
• Reinstall the carburetor bowl.
• Reinstall the screw to hold the bowl and carburetor together.
• Wipe down the carburetor again to remove any spilled fuel
• Turn on the fuel supply and check for additional leaking from the carburetor.

Stuck carburetor float

Next, look for a fuel leak near the air intake port. When you find a leak in this area, you could have a stuck float that can no longer regulate fuel flow into the bowl. Fuel keeps flowing into the carburetor bowl and then overflows out of the carb when you have a stuck float.

Take your carburetor apart when you find a stuck float to determine the actual cause of the failure. You may be able to clean the carburetor to keep the float from sticking.

You may also have to rebuild it to get your carburetor to work right. Read the steps to clean your carburetor in this article.

Stuck float needle

The last thing you should check on your carburetor is the float needle. The float needle works in conjunction with the float to keep gas flowing into the carburetor bowl. If the needle gets stuck, it will need to be repaired.

You will have to take your carburetor apart to fix the float or you can take it to your local small engine mechanic to have the carburetor rebuilt.

Some Ariens owners tap on their carburetor gently with the rubber handle on their hammer or with a rubber mallet to free the needle. This does work a time or two, but it is only a temporary fix.

Fuel Filter is Cracked or Deteriorating

Fuel can cause degradation in plastics like that used for an Ariens inline fuel filter. The filter can begin leaking at the seams when your filter deteriorates. It can also leak if the plastic is cracked. A leaking fuel filter needs to be replaced.

Be careful when removing the ends of the inline filter from your fuel lines as the plastic can become soft and break off. You can find a replacement inline fuel filter online or at your local hardware store.

The type of fuel you use in your Ariens mower and how you store it can affect your fuel system. Read more about the effects of ethanol and the best way to stabilize the gas for your Ariens lawn mower here.

Bad Fuel Pump

Your vacuum fuel pump can wear over time because the makeup of fuel today can degrade plastics causing leaking at the plastic seams. When the plastic is compromised, your fuel pump is no longer able to build the pressure it requires to pump fuel to the carburetor.

A fuel pump with a fuel leak must be replaced. You can purchase one at your Ariens dealership or online for your Briggs, Kawasaki, or Kohler engine.

Failed Seams on the Fuel Tank

Fuel tanks used on Ariens lawn mowers are made with high-density polyethylene. The seams on the tanks can fail to cause your fuel tank to leak. The best solution is to replace your fuel tank with a new tank.

Faulty Fuel Shut-Off Valve

Your Ariens mower may have a valve on the bottom of the fuel tank called the fuel shut-off valve. Its function is to start and stop fuel flow. Your valve can leak whether it is made of plastic or metal. You need to replace your fuel shut-off valve when you find it leaking gas.

Dry and Cracked Fuel Lines

Fuel lines can become dry and brittle with age. They can develop cracks where gas can leak from your Ariens.

Another place that is known to leak is in the areas where clamps are used to secure your fuel lines. The clamps can either be loose or puncture the hose causing fuel to leak out of your Ariens’ fuel line.

Any cracked fuel lines need to be replaced. This may also be a good time to replace your fuel clamps if your mower uses a pinch-style clamp. I like using a worm gear clamp because they are less likely to pinch your lines and cause leaking.

Bad Gas Cap Seal

When your gas cap doesn’t seal, your Ariens can form a leak around the cap. If you smell gas and went through all the above checks for a gas leak and still can’t find it, you should definitely check the seal in the gas cap.

A leak around the cap will leave a wet spot for a short time before it evaporates and doesn’t leave a sign of leakage. To determine if your cap is sealing, rock your mower back and forth to splash gas up around the cap area and watch for wet areas to develop around the cap.

Replace a gas cap with a new cap when you see signs of gas around the cap on the outside of the fuel tank.