12 Reasons Why a Kubota Lawnmower Starts Then Dies

I don’t know about you, but I’ve had moments when my lawn mower just sat there in the middle of the yard, lifeless. My son probably forgot to check the gas before he began cutting the grass, or a component broke.

Old gas, a clogged fuel filter, clogged fuel lines, a dirty carburetor, a clogged air filter, a faulty fuel cap, a faulty spark plug, a faulty ignition coil, a clogged mower deck, or insufficient engine oil can all cause a Kubota lawn mower to start but quickly die.

Always follow the safety instructions in your operator’s manual, which may include:

  • Remove the ignition key and spark plug wires before performing maintenance on the mower.
  • Be careful when working near a hot engine.
  • Wear eye protection to prevent fluids or dirt from entering your eyes.
  • Guard your hands against sharp components.


Before diagnosing, repairing, or operating, make sure you’ve read and understood all of the safety instructions in the equipment’s operator’s manual. If you don’t feel confident in your ability to make the necessary repairs, whether due to a lack of experience or health, you should get in touch with a professional.

Causes of a Kubota Lawnmower’s Untimely Death

Bad or Old Fuel in a Kubota Lawn Mower

If your Kubota lawnmower runs on gas, using old gas will reduce its performance. If your mower starts but quickly dies, this may be the problem. That’s because gas can corrode and gum up the fuel system, rendering it useless.

Ethanol is found in most gasolines sold at gas stations. It’s a chemical compound that’s blended into gas to make it safer for the planet. This is due to the fact that a plant with a high starch content, like corn, is used to produce ethanol.

It’s better for the planet, but it won’t work in your Kubota’s little engine. Moisture in the air accelerates corrosion, and ethanol’s residue, a varnish, can clog fuel injectors. If the fuel supply is inadequate, the engine will sputter and eventually stop working.

It’s best to use gasoline within 30 days of purchase to prevent it from going bad. If you have more gas than you need or if you just want to be extra careful about keeping the fuel system clean and the gas stable, you should add a fuel stabilizer.

For prolonged fuel stability, use a product like Sea Foam Motor Treatment or STA-BIL. The fuel can be stabilized for up to two years. Before purchasing an additive, make sure you know how long it will keep gas stable by reading the label.

Every time I fill up the tank, I put Sea Foam in it. See “Use Sea Foam Additive in a Lawn Mower to Stabilizer Your Fuel” for more information on the benefits.

Solution: If the gas has been sitting for a while, you should flush the tank with a fuel siphon pump. The gas tank needs to be refilled. Your fuel can be stabilized, and the moisture can be reduced and the fuel system cleaned, all by adding an additive.

Kubota Lawnmower with Attached Air Filter

A malfunctioning air filter is a common maintenance issue that can prevent your Kubota from functioning normally. Mowing creates dusty conditions, so the air filter can clog if it isn’t regularly changed or replaced.

Particles in the air intake can cause damage to the engine, but the air filter keeps those particles out. Mow with a clean air filter at all times. Mower damage can be increased by overheating if this isn’t done.

The air filter should be changed once a year and maintained with regular cleanings throughout the mowing season. Before each mowing, you should inspect the filter. You can do the check in under two minutes.

Solution: Take out the dust collector to see if it has become clogged. Air filters can be easily maintained by following these instructions.

Clean a Kubota Paper Air Filter Element:

  • The air filter housing and cover should be cleaned after the filter has been removed. Take care that dust doesn’t get sucked into the fan.
  • Lightly tapping the filter against a hard surface can help loosen and remove any dust or debris that has settled on it.
  • It is possible to see through the filter if you hold it up to a light. Don’t throw away your air filter if it can be used again. If you can’t clean the filter, or if it’s damaged or clogged with oil, you’ll need to buy a new one.
  • Repeat this process for the air filter, and then replace the cap on the filter housing.

Kubota Lawnmower with a Clogged Fuel Filter

The fuel in a Kubota lawnmower is filtered through a fuel filter. It keeps debris and other foreign particles out of the fuel supply. Over time, your fuel filter could become clogged due to dirt and gummy deposits in your fuel.

Most fuel filter problems can be avoided during the mowing season if the fuel filter is changed every year.

Solution: To fix a clogged fuel filter, you need to remove the old one and put in a new one. On the side of your fuel filter, you’ll see an arrow.

Place this arrow in line with the fuel intake on your lawnmower. A fuel filter’s correct orientation is toward the carburetor, not the fuel tank.

A Kubota Lawnmower with Clogged Fuel Lines

It is possible to completely block fuel flow through your fuel system if your fuel lines become clogged with the gummy deposits left behind by running old fuel. When this happens, the Kubota mower may suddenly stop working.

Turning off the fuel at the shutoff valve in the fuel tank is the best way to check each section of the fuel line. Pinch off pliers can also be used to crimp the fuel line and stop the flow. Gather the fuel line that was disconnected from the fuel pump. You need to turn on the gas.

Turn off the fuel and reconnect the line if you have enough going into the storage tank. It is time to move on to inspecting the remaining fuel components for any signs of obstruction or failure.

Solution: If fuel is not flowing smoothly from the fuel line into the container, it may be because of a clog in the fuel filter or another part of the fuel line.

Once you’ve located the clogged area of the fuel line, you can disconnect that section of the line from the mower and turn off the fuel supply. To break up the clog, spray carburetor cleaner into the pipe.

The next step is to clear the line by blowing compressed air through it. Any number of times that you feel is necessary. If you are unable to remove the obstruction, a new fuel line must be installed.

An Unclean Carburetor on a Kubota Lawnmower

Carburetors are used to control the ratio of fuel to air in your engine’s combustion process. Your mower won’t keep going if it starts but quickly dies due to a faulty carburetor.

Running old fuel that has been sitting in your carburetor causes gummy and hard deposits to form, making your carburetor dirty. As a result, parts of your carburetor might start to restrict fuel flow.

Solution: Make sure fuel is reaching the carburetor before you start dismantling it. Once that’s established, you can take out your air filter and spray carburetor cleaner into the intake.

Kick off the mower. Taking it apart and cleaning the carburetor may help if it dies after being run. To clean your carburetor, just use this guide as a blueprint.

Damaged or Clogged Kubota Lawnmower Cooling Fins

When the engine gets too hot, a Kubota mower won’t start. Verify the cooling fins in your engine. They could be broken or clogged with debris.

The purpose of the cooling fan is to circulate air around the engine block and cylinder head, thereby reducing the temperature of those components. If your engine’s cooling fins get clogged up, less air can flow through them.

Solution: You should exercise caution when working near a hot engine. Take out the trash that’s blocking the cooling fins. Take care of any damaged fins by replacing them. Remove any obstructions from the engine and its cover. Make sure the heat shield is firmly fastened.

Low Engine Oil in a Kubota Lawnmower

For optimal performance, the engine in your mower needs a certain amount of oil in the crankcase. When the oil level in your engine drops too low, issues can arise; however, few people realize that when the oil level in your crankcase rises too high, problems can also arise.

Too Much Engine Oil in a Kubota Mower

Now you need to make sure the mower’s engine has enough oil. If you fill the crankcase of a Kubota lawnmower with too much engine oil, the crankshaft will be damaged. Mower breakdown from overheating is a distinct possibility. Find out more about what happens when you put too much oil into a Kubota mower by reading this article.

It may be necessary to drain some oil from the engine or replace the oil filter. It is also possible to use a turkey baster or oil evacuator to siphon oil from the engine oil fill port. Once you’ve used the turkey baster, throw it away and don’t use it again.

Locate the dipstick and examine the oil level. Keep adding or draining oil until the full line appears on the dipstick.

Too Little Engine Oil in a Kubota Mower

It’s possible that your engine has developed an oil leak or that it’s using or burning oil. Lack of adequate oil for lubrication causes internal engine parts to grind together, which generates heat.

Your engine could overheat and shut down if exposed to this much heat. Sometimes the temperature rises so high that the internal components of your engine begin to melt.

The bad news is that if your engine dies from a lack of engine oil, it will likely be severely damaged.

The best thing to do is have a skilled small engine mechanic disassemble your mower’s engine and run diagnostic tests to see how much damage has occurred.

Bad or Dirty Spark Plug on a Kubota Mower

Inefficient operation and eventual breakdown can be the result of a Kubota mower’s spark plug becoming dirty or fouled. In addition to a dirty plug, a damaged plug, a plug with improper gapping, or a plug with wires that aren’t attached securely can all cause your mower to stop working.

Solution: Bring your spark plug tip back to life by cleaning it. Replace your spark plug if you notice that the tip is very dark, the electrode is burnt, or the plug is broken.

Follow the engine manufacturer’s recommended air gap on the plug. Put a spark plug wire on each spark plug and make sure it’s attached tightly. A spark plug won’t break the bank. These should be changed out every year.

Bad Ignition Coil on a Kubota Mower

When the mower is hot, the winding on the Kubota ignition coil can come unwound and cause a short. This prevents spark plugs from receiving the voltage they require to create spark. After a while of use, this can cause your mower to stop working.

Solution: Use an ohmmeter to check for a lack of continuity to pinpoint a malfunctioning ignition coil. If you discover a broken ignition coil, you should have it replaced immediately.

On a Kubota mower, the choke is in the incorrect position.

When trying to start a cold engine, the choke is engaged. By decreasing the amount of air entering the engine, the choke improves the fuel-to-air ratio necessary for combustion.

The engine will not keep running unless the choke is opened up after it has warmed up. The Kubota won’t make it past the starting phase if this isn’t fixed.

Solution: Check that the choke lever is in its proper position.

Faulty Kubota Mower Gas Cap

Having a vent in the fuel tank is necessary to maintain a constant internal air pressure of atmospheric pressure. The gas cap on a Kubota engine serves as an exhaust.

A vacuum is created in the fuel tank when the vent is blocked, preventing gas from reaching the engine.

Running the mower with and without the gas cap for set amounts of time can help you figure out if the cap is broken and not allowing gas to vent.

If your mower dies while running with the fuel cap on and won’t restart, try releasing some air from the tank by loosening the cap. A faulty fuel cap could be to blame if starting and running is successful.

If the Kubota cuts off and won’t start again until the cap is loosened, then you know the problem is with the cap.

Solution: Replaced a damaged fuel cap on a Kubota.

Plugged Kubota Mower Deck

A Kubota awn mower will stop working if the mower deck is clogged with grass and other debris. Because the engine has to work harder to rotate the blades through the junk on the deck, higher fuel consumption is the result. If your mower deck is already clogged up, having dull blades can only make matters worse.

Solution: Avoid this by keeping a regular schedule of scraping your deck. Get those mower blades back in shape. Avoid mowing when it’s raining or snowing because wet grass clumps and sticks to your mower deck.

A deck spray can be used to prevent excessive grass growth. While deck sprays won’t eliminate buildup entirely, they can significantly cut down on the amount of dirt and dust that settles there.

Why isn’t the battery in my Kubota lawn mower charging?

Keep the engine speed high when using a Kubota mower. Don’t leave your mower idling for too long. The battery can only be charged using the engine’s power.

You may have a problem with the charging system if you find yourself constantly recharging the battery despite ensuring the battery and wiring are in good condition and securely attached.

Solution:  I’ll show you how to inspect your battery and charging system for problems. You should get a new battery if any of these tests reveal that your current one is defective.

If you discover that your vehicle’s charging system is malfunctioning, you should have a professional mechanic inspect it and fix it.

If you don’t know what you’re doing and just throw parts at the charging system, you might get lucky and fix the problem.

Due to their nature, electrical components are typically non-returnable and can quickly rack up in price.

Still Having Issues with Your Kubota Lawn Mower?

Long-term ownership of a lawnmower almost guarantees that you will eventually experience starting or running difficulties, smoking or leaking gas, an uneven cut, excessive vibration, or some other problem.

I’ve compiled this manual to help you save time and money the next time your Kubota mower breaks down.

Common Issues with Kubota Lawn Mowers and How to Fix Them.

If you don’t feel confident diagnosing and fixing your Kubota lawnmower on your own, you should hire a pro.

You’ll save yourself from harm and the mower from further destruction by doing this. If you’re having trouble with your lawn mower, head on over to the nearest Kubota dealer or repair shop.