Your mower is running sluggish and almost acts like it’s going to shut off. This may be due to a fuel restriction in the fuel system or a failed component. I have put together a list of items to check that can keep your mower from running due to a lack of fuel.
A riding mower will not get fuel when old fuel has caused clogging and degrading of fuel system components. This can cause a plugged fuel filter, clogged fuel lines, a dirty carburetor, and a failed fuel pump.
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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.
This is Why Your Riding Mower is Not Getting Fuel
Using Bad or Old Fuel
Gasoline in your mower can go bad and not be as effective. Much of today’s gasoline includes ethanol, an environmentally friendly corn-based fuel.
Ethanol is okay to run in most vehicles, but it is not good for small engines like the one in your mower. Because of this, make sure you are using a fuel with an ethanol content of 10% or less.
Gas begins to break down as soon as 30 days after purchase. Ethanol, and the moisture it attracts, separate from the gasoline leaving behind a sticky substance when it evaporates.
This substance can gum up your fuel components resulting in a lack of fuel for your engine.
You can find out more about choosing the right gas for your riding mower in this article. I go into more detail about the types of fuel to choose and the harmful effects of ethanol.
Repair: When you find old fuel is your problem, drain your fuel into an approved fuel container. Make sure it is a container designed for gasoline because plastics can degrade quickly and leak fuel.
I like to use a siphon like this one to drain the fuel. Set aside your fuel to be taken to an authorized recycling center to be disposed of.
Refill your fuel tank with a gas including a fuel additive to your fuel. I use Sea Foam Motor Treatment in my mower. This fuel additive not only stabilizes gasoline but also acts as a fuel-cleaning agent. Read more about the additional advantages of using Sea Foam here.
Fuel Filter is Plugged
Your fuel filter strains out dirt and contaminants from the fuel system. It can get plugged and not allow fuel to pass through the filter. Replacing your fuel filter annually when servicing your riding mower can greatly reduce problems with the filter during the mowing season.
Repair: A plugged fuel filter must be replaced. You will find an arrow on the plastic housing of the fuel filter. When installing your new filter, make sure the arrow is pointed in the direction of your fuel flow.
The arrow should be pointed away from the fuel tank and toward the carburetor.
Fuel Lines are Clogged
The sticky substance I referred to earlier can clog your mower’s fuel lines. When this happens, your mower won’t be able to get fuel causing running problems. To find it, stop and start the fuel flow as you check each section of your fuel line.
Repair: Use the fuel shut-off valve located at the bottom of your fuel tank or hose pinch-off pliers to crimp the line and stop the flow. When checking a fuel line, disconnect the hose from the end furthest from your fuel tank.
Place this end in a container and start your fuel flow. When you see flow into the container, you have confirmed that the section of the fuel line does not have a blockage.
Once you find a section of the fuel line that is clogged, remove the line from your riding mower. Spray carburetor cleaner into the line to help loosen the clog. Follow by blowing compressed air through the line to remove the clog.
If you are unable to unclog the line or the fuel line is dry and cracked, it’s time to replace your fuel line.
Bad Fuel Pump
Most mowers use a vacuum-style fuel pump to pump fuel from the fuel tank to the carburetor. A vacuum pump builds pressure off the crankcase to pump fuel.
The fuel pump can become damaged, wear or degrade. If you don’t notice a physical damage, cracks, or fuel leaking from the pump, you must complete troubleshooting procedures to verify your pump is bad.
FIX: Before you check the fuel pump, check to make sure you are getting fuel to the fuel pump if you didn’t already complete this step when checking for fuel line blockages.
Stop the fuel flow. Remove the fuel line off the inlet port of your fuel pump. Place the line in a container placed lower than the fuel tank and restart your fuel flow.
If you are getting fuel out of the line and into the container, you have confirmed you have flow. If not, you need to find the blockage that may be in your fuel lines or fuel filter.
Once you have confirmed fuel flow to the pump, reattach the fuel line to the inlet port. Remove the fuel line from the carburetor and place it in a container. Check your pump is working correctly by starting your fuel flow and starting your mower.
You should have a steady or pulsating flow of fuel coming out of the fuel line. If you do not, you need to replace your fuel pump so you can continue to get fuel to your riding mower.
The carburetor’s function is to regulate the air and fuel your engine requires. When the carburetor is dirty and clogged from old fuel sitting in the carburetor, it can prevent your riding mower from getting adequate fuel.
There are many small components in a carburetor that can stick or become clogged.
Before you start tearing apart your carburetor, perform a quick procedure to confirm you actually have a problem inside the carburetor. You don’t want to disassemble the carburetor only to find it isn’t the problem.
First, remove the air filter and spray carburetor cleaner into the air intake. Next, start your mower to see if it starts, runs, and then shuts off. If it does, proceed with cleaning your carburetor.
FIX: If you are a little mechanical and don’t mind working with many small parts, then you should be able to tackle the job of cleaning your carburetor. Follow the steps in this article to disassemble and clean your carburetor.
Don’t feel up to cleaning your carburetor yourself? No worries. Your local lawn mower repair shop will be able to do this for you. You can also purchase and install a new carburetor as well.
It’s important to take care of your fuel system to minimize clogging and damage to your fuel components and engine. To protect your fuel system, you must start out using the right kind of gas.
Adding a fuel additive to reduce moisture and stabilize your fuel will help minimize clogging in your riding mower. Learn more about fuel stabilizers here.
Still Having Problems With Your Riding Mower?
As a lawn mower owner, when you own it long enough, you are going to run into different types of problems. This may include problems where your mower is smoking, cutting unevenly, losing power, not starting, leaking fuel, and more.
Check out this handy guide including charts for common mower problems and solutions:
Common Riding Lawn Mower Problems & Solutions.
If you are unable to fix your mower or don’t want to attempt a more complicated repair, have your local lawn mower dealership or repair shop for assistance.