Water in Gas Lawn Mower: Why + How to Get it Out

Water can get into lawn mower gas tank when using a fuel containing ethanol. It attract moisture into the fuel tank that condense into water. Keeping the lawn mower out in rain or damp places also increases the chances of water seeping into the fuel tank to cause performance problems. So, how do you tell if there is water in gas lawn mower tank and what should you do?

How can Water get into Lawn Mower Gas Tank?

There are several ways that water can get into lawn mower gas tank:

Using Fuel Containing Ethanol

Using fuel containing ethanol increases the chances of water getting into lawn mower gas tank. Ethanol draws moisture from the air which condense inside the fuel tank to form water. It usually happen in winter break when you fail to drain off lawn mower fuel tank.

If the lawn mower is not in use for more than a month, it’s recommended to drain off the gas tank. Alternatively, use fuel stabilizers to keep the gasoline fresh for a long period of time.

Other than attracting moisture into mower gas tank, prolonged stay of gas in fuel tank will block fuel filters, fuel lines and carburetor. The gas evaporate leaving behind sticky substances that clog fuel filters, fuel lines and carburetor.

Keeping Lawn Mower Out in Rain

It is advisable to keep your lawn mower in a safe shelter away from environmental hazards. Forgetting to keep your mower in a safe place on a rainy weather can expose the gas tank to rain water especially if the gas cap it not tightly fitted. Lawn mower getting rained on is thus not a good idea.

Improper storage of a lawn mower

Water can enter the fuel tank through condensation if you store the lawn mower in a dump and humid locations where it warm up during the day and get cold overnight. This process usually create a vacuum that pulls in moist air into fuel tank. It condense into water and settle at the bottom of gas tank.

How to tell if there is Water in Gas Lawn Mower

Contamination of the fuel tank with water can cause severe performance problems. Prolonged contamination can cause corrosion or rust to the fuel tank and carburetor components. Diagnosing this problem will help to fix the problem. Here is how to tell if there is water in lawn mower fuel tank:

1. Hard Start

Cranking the pull cord severally but nothing happens? There are several issues that cause this problem. One of them is presence of water in fuel tank. Lawn mower won’t start if there is water in the gas tank. Water is denser than gas and will sink at the bottom of the fuel tank.

Since most lawn mowers are designed to draw fuel from the tank bottom, the mower will draw water first into the carburetor to cause the hard start.

2. Poor Engine Performance

If the lawn mower is starting but keep on revving up and down could be indicating presence of water in fuel tank. The water may not be enough to stop the engine but it is significant to affect performance.

In some cases, the engine may be running but stops when engaged or increasing the throttle. The only solution to this problem is empting the tank to get rid of the water, cleaning the carburetor and fuel lines to remove traces of water.

3. Start but Sputters

Small amount of water in gas tank will cause the engine to start smoothly followed by sudden sputter. The engine may also stall or stop running completely. This happen when there is little fuel that allow start up but fail to maintain combustion. The same thing will reoccur when restarting the engine.

4. Excess Smoke from the Engine

Unusual amount of smoke coming out of a lawn mower engine may also indicate presence of water in the gas tank. Excess smoke can result from poor fuel combustion in the piston chambers. The smoke is usually accompanied by fuel smell.

5. Fuel System Damage

Prolonged presence of water in the fuel tank can lead to serious fuel system damages such as corrosion or rust. If you notice performance issues created by presence of water in the gas tank, it is important to check your lawn mower as soon as possible to fix the problem.

How to get Water out of Lawn Mower Gas Tank

If you realize presence of water in lawn mower fuel tank, it is importance to get it out as soon as possible before it causes a serious damage. The tips below provides step-by-step guide on how to fix this problem.

1. Take the lawn mower into garage and assemble the necessary tools

You are basically going to remove the fuel tank, fuel lines and the carburetorfrom the mower to get rid of the water. Therefore, you will need a safe place and necessary tools to do the job. Fortunately, you won’t need much, a socket wrench, screwdriver, pliers and flathead screwdriver are enough.

2. Disconnect the spark plug

For safety purposes, remove the spark plug before doing anything else. Remove fuel filter and loosen the fuel tank bolts and disconnect it from the mower. Be sure to remove the governor springs by bending them down. The fuel tank should be able to come out with ease.

3. Empty the fuel tank

Empty out all of the gas contaminated with water into a special container that is set aside for that purpose. Remove the primer assembly from the gas tank to access the reservoir that will be containing contaminated fuel. Be sure not to damage the gasket and diaphragm when opening the reservoir for clean-up.

4. Dry the gas tank

Insert a dry piece of cloth into the tank to clean up contaminated fuel residues at the bottom and sides of the tank. Move it inside the tank using a long screwdriver to ensure it reaches all the corners. Use pliers to remove it from the tank when done with cleaning.

5. Empty the Carburetor bowl and fuel lines

Dis-assemble the carburetor and empty the carburetor bowl. Use carburetor cleaner to clean the carburetor. Dip paper towel into carburetor cleaner and wipe thoroughly all around the bowl. When done, reassemble the carburetor. Ensure the fuel lines are empty and free from contaminated fuel.

6. Re-attach fuel lines, carburetor and fuel tank

When you are done with cleaning, re-attach everything. Be sure all the bolts are tightly secured. Fix back the spark plug onto the cylinder.

7. Refill the tank

Refill the tank with fresh gasoline and start the engine. The lawn mower should be able to run smoothly. If you live in an area with moisture problems, be sure to use fuel additives to combat this problem.

Final thoughts

It is always recommended to store your lawn mower in dry and safe shelter. Keeping it out in rainy weather or damp shed increases chances of water seeping into the fuel tank. Contamination of gas by water can cause severe performance problems. Empty the tank, dry it and refill with fresh oil to fix this problem.

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