When your zero-turn mower isn’t getting fuel, it can run sluggish and act like it is going to shut down. It may even do just that and no longer start.
Because you have narrowed your running issue down to a fuel supply problem, there aren’t too many items to check on your mower to isolate the problem. Keep reading and I’ll share with you the items to check on your zero-turn when looking for your fuel issue.
A zero-turn mower will not get fuel when old fuel has clogged the fuel lines, fuel filter, and carburetor components. A fuel pump or fuel cap failure can also cause fuel restrictions and fail to allow your zero-turn to get fuel.
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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.
6 Reasons Your Riding Mower Isn’t Getting Fuel
Bad or Old Fuel in Your Zero Turn Lawn Mower
It is highly likely bad or old fuel has contributed to your zero turn’s lack of getting fuel. Most zero turns on the market today are gas-powered. I’m going to address gasoline problems first before discussing diesel problems.
Gasoline for Zero Turn Mowers
Most gas sold at fuel stations today contains ethanol, a corn-based fuel, that has been added to make fuels more environmentally friendly.
While adding some ethanol to fuels doesn’t hurt most vehicles we run on the roads, it can hurt the small engine in your zero-turn mower. Because of this, it is important to run gas with no greater than a 10% ethanol content.
Gas can begin to break down and become less effective as soon as 30 days after purchase. When it breaks down, the ethanol and moisture it attracts will separate.
This can leave behind a gummy substance when it evaporates causing clogging in your fuel system. This will prevent your zero-turn from getting the fuel it requires.
In addition to clogging your fuel system components, ethanol can begin degrading your fuel components causing them to fail.
Gasoline that contains ethanol can cause plastics to soften and corrode metal components. Find out more about the right type of gasoline to run in your zero-turn mower.
Diesel for Zero Turn Mowers
Diesel-powered zero turns, with diesel that has been sitting for a long period of time, can form solids in the tank and form condensation that can clog your fuel system and damage components. Old diesel fuel degrades and will have a dark appearance.
Make sure you are purchasing fuels from a busy fuel station that cycles through diesel frequently. I like to find one that has separate diesel fuel pumps where there is a constant flow of diesel truck traffic.
I have had a bad experience purchasing diesel fuel from a reputable fuel station that, when I look back at it, was busy with gas-powered cars and not many diesel vehicles. I found my filter turned black after running their diesel fuel.
Repair: Remove old fuel using a fuel siphon and place it in an approved fuel storage container for recycling. Fill with fresh fuel. Add a fuel additive to stabilize and clean your fuel system.
I prefer to use Sea Foam Motor Treatment. It is a petroleum-based product safe to use in diesel and gasoline-powered zero turns.
Want more information on Sea Foam? No problem! I’ve put together an article to show you the advantages of using Sea Foam. I also list some additional alternatives as well. If you are unable to get Sea Foam because you live outside of the United States, another great product is STA-BIL.
Fuel Filter is Plugged on Your Zero Turn Mower
Your fuel filter exists to prevent dirt and contaminants from entering your fuel system and causing damage to the fuel system and engine.
It is good practice to change your fuel filter annually during your zero-turn service maintenance. A fuel filter can become plugged preventing your zero-turn from getting fuel.
Repair: Replace a clogged fuel filter with a new filter. When installing the new filter, make sure the arrow on the side of the plastic housing is installed in the direction of fuel flow. The arrow should be pointed away from the fuel tank and toward the carburetor.
Fuel Lines are Clogged on Your Zero Turn Mower
A gummy residue can form in your fuel system from running old fuel. This can result in clogs forming in your fuel lines preventing fuel from flowing to your engine. To find a blockage in your fuel lines, stop and start fuel flow with your fuel shut-off valve or by crimping your fuel line.
Repair: Stop your fuel flow. Disconnect the end that is furthest from your fuel tank when testing a section of the hose. Place that end in a container and start your fuel flow.
Your fuel line is blocked when fuel is not running through your fuel line into the container. (Make sure the fuel hose is allowing fuel to run downhill when performing the test).
With your fuel flow shut off, remove the section of the fuel hose with the clog. Spray carburetor cleaner in the hose to loosen up the clog. Follow this with compressed air to blow air through the line and unclog the hose. Reinstall the hose once the blockage has been removed.
If you are unable to clear the blockage, replace your fuel line with a new line. It is also a good idea to replace your fuel line if you find it is dry and cracked.
Bad Fuel Pump on Your Zero Turn Mower
Most zero-turn mowers utilize a vacuum-style fuel pump to pump fuel from the fuel tank to the carburetor. A pump is required because the fuel tank sits lower than the carburetor. Gravity naturally won’t allow fuel to move upward without a pump.
The fuel pump can become damaged, degraded, or just stopped functioning properly. Without a good working fuel pump, your zero-turn will not get the fuel it requires to start and run.
Before you start checking the fuel pump, confirm you are getting fuel to the pump. You may have already done this in the previous steps when you checked for blockages in the fuel lines.
Once you know you have fuel running through the lines to the inlet port of the fuel pump, you can go ahead and test your fuel pump.
Repair: Test your fuel pump by removing the fuel line from the carburetor and placing it in a container. Start your engine and watch for a pulsating or steady flow of fuel being pumped into the container.
If your pump is failing to adequately pump fuel into the container, it is time to replace the pump with a new one.
Dirty Carburetor on Your Zero Turn Mower
A carburetor regulates the right ratio of fuel to air required by your engine to form a combustion. When components of your carburetor stick and gum up, fuel may not get to your zero turn’s engine.
Your carburetor will need to be cleaned to remove any clogs that are preventing fuel movement.
Before you start tearing apart your carburetor to clean it, perform a simple check to confirm the problem lies in your carburetor. The last thing you are going to want to do is to pull your carburetor off the mower and disassemble its many small parts to find it doesn’t fix your problem.
Check for a carburetor problem by removing your air filter from the air filter housing. Spray some carburetor cleaner into the air intake. Start your mower. If it fires up, runs, and then shuts off, you need to take apart your carburetor to clean it and replace any damaged parts.
Repair: If you are a little mechanical and don’t mind working with small parts, follow these instructions in this article for steps to clean your zero-turn carburetor.
If you are not that mechanical or just don’t feel up to tackling the job, your local small engine repair shop can clean it for you. You can also swap out the carburetor with a new one so you don’t have to tear it apart.
Bad Zero Turn Fuel Cap
Fuel caps are designed to vent. There is a small hole in the cap that allows air to pass through the cap. When the fuel cap vent is plugged, the fuel tank forms a vacuum restricting fuel flow so your mower will not start or run.
Repair: Run your mower with and without your fuel cap to test whether or not you have a fuel cap problem.
If your mower runs well with the cap removed, replace the cap and let the mower run for a while. If it shuts down, there is a good chance your fuel cap is not venting.
You can attempt to clean your fuel cap to remove the clog. If this does not work, purchase a new fuel cap.
Summary
Keeping your fuel system in good working condition starts with using fresh clean fuel. When you are unable to use your fuel within the first month, add a fuel additive to stabilize the fuel so it keeps longer without breaking down.
A fuel issue can be found by starting at your fuel tank and following the fuel line to check all fuel components.
Zero Turn Mower Will Not Start After Checking Your Fuel System
If you have checked your fuel system and found all of your fuel components are good and your zero-turn still won’t start and run, you may not actually have a problem with your fuel system.
You may have a different problem that can cause your zero-turn to fail to start. Read this article for reasons your zero-turn mower may not start.
Still Experience Problems with Your Zero Turn Mower?
Many different types of problems can develop in a mower. It doesn’t matter what brand you own.
While some mowers are built with stronger materials, bigger filters, better engines, and tougher spindle housings, they are all going to break down and cause issues at some time. Some may just not develop problems as quickly as others.
I put together a guide with common things that go wrong on zero-turns. In this guide, you will find a list of causes and solutions for a mower dying, smoking, vibrating, not starting, having cutting issues, and more.
Check out my guide at Common Zero Turn Mower Problems: How to Fix Them
If you still can’t find the solution to your problem or you don’t feel comfortable troubleshooting or repairing your mower, it is best to have an experienced mechanic check out your mower.
You can visit your local dealership that provides repair support for your brand mower. You may also find a lawn mower repair shop with experienced small engine mechanics.