If your John Deere mower died while mowing, various reasons could be the culprit. While most of these are easy to detect, troubleshoot, and fix, you must know where to look to succeed.
Knowing why the John Deere tractor keeps shutting off can save you a lot of frustration, especially if the mowing vehicle shuts off in the middle of your work.
For minor problems, you can quickly fix the issue and return to work. However, if the problem requires a more elaborate solution, you can still save money by fixing it yourself instead of hiring a professional.
Why John Deere Tractor Keeps Shutting Off
A John Deere mowing tractor can die after starting or in the middle of its operation due to a fuel delivery issue, air filter issue, spark plug malfunction, bad ignition coil, bad fuel, low fuel, fuel shut-off solenoid malfunction, or clogged gas cap vent.
Any of these factors can rob the engine of air or gas, making it unable to continue running. This forces the engine to shut off involuntarily.
So, if your John Deere Tractor keeps shutting off, here are the common reasons likely to be responsible.
1. A Clogged Mower Deck
The mower deck houses the blades responsible for cutting grass. After working for a while, accumulated grass can clog the deck, especially if you are cutting wet grass.
This mass of debris affects the quality of cuts you get while mowing. Additionally, it creates additional work for the engine, which must push harder to get through the accumulated dirt and grass.
If your John Deere tractor runs then dies, your clogged mower deck might have created too much work for the engine, forcing it to shut down.
How to fix it
Frequently sharpen your lawnmower blades and scrape the cutting deck to prevent debris accumulation in this area.
Mowing in dryer conditions can also help prevent this accumulation, as wet grass tends to mix with dirt more easily.
2. Bad Fuel in the John Deere Lawnmower Tank
If your John Deere riding mower stopped running suddenly, bad fuel might be in the tank. Many users rarely notice this, but bad fuel can contain chemicals likely to cause a fuel delivery problem by clogging it.
If you use gasoline, your John Deere tractor may stop working due to expired gas. Gasoline typically goes bad after 30 days. So if you have had it in your mower’s tank for that long, it will no longer work.
So always check the quality of the fuel you put in your mowing tractor to avoid such gas-related problems.
What to do
The only way to resolve this problem is to drain the old fuel in your John Deere mower tank and flush it for a fresh restart. After cleaning the tank, you can refill it with fresh gas to power the mower.
Consider going for fuel with a cleaner and stabilizer in its formula to prolong its service life if you intend to keep it in your tractor for a long time.
Fuel stabilizers are designed to keep gasoline from breaking down and going bad in your vehicle.
Fuels with ethanol in their formula tend to decompose fast, but adding a stabilizer can keep the fuel sound for up to six months or longer.
You can find fuel stabilizers under generic names like Dry gas. This additive helps keep moisture in the fuel tank or filter from freezing.
Another product that you can add to your gasoline to clean and stabilize it is Sea Foam.
Alternatively, use ethanol-free options on the market if you can afford to pay more for the fuel. You should find such options in fuel stations or local hardware stores.
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3. Clogged Fuel Filter
Water, organic debris (molds and microbial bacteria), and inorganic debris (rust, sand, and dust particles) are common contaminants that end up in the fuel during production.
These contaminants can clog the fuel filter in your tractor over time. Clogged fuel lines such as between the injector pump and filter cause fuel delivery problems for your John Deere mowing tractor.
Old fuel is a major culprit in this regard. While we often want to keep some fuel around to use when the need arises, that need may arise when the fuel has decomposed.
Due to increased demand for fuel, refineries now use production methods that yield fuel with shorter service life.
Much of the fuel produced today is less stable, with molecules that turn into gums, sludge, and sediments as the product degrades.
Whether you use diesel fuel or gasoline, you can expect it to start degrading within a few weeks of storage.
As it stays in your tractor’s gas tank, the resulting contaminants will end up in the fuel lines or the filter from the fuel intake side.
Once these blockages occur, they restrict the engine’s access to the fuel. This situation leads to reduced fuel pressure and a lean fuel condition that causes the engine to misfire.
What to do
When the fuel lines are clogged, you can resolve the problem by clearing the clog or replacing the affected filter.
The fuel lines or hoses are the conduits that transfer the gas from the mower’s fuel tank to the engine. So, start by diagnosing the problem to identify the precise points with the blockage.
You can crimp the fuel hoses using the vehicle’s fuel shut-off valve, starting and stopping the fuel flow to allow you to examine them for blockages.
After identifying the clogged sections on the fuel line, spray them with a carburetor cleaner to loosen and remove the blockage.
You may have to clear out the loosened clogs with compressed air. Next, remove your fuel filter and check it against light for signs of blockage.
You should be able to see the light through the filter if it is good. Otherwise, you must replace it even if you don’t replace the fuel pump.
Alternatively, you can bypass the filter and test the tractor to see if it runs without the fuel filter. If it does, you must replace the filter.
4. A Dirty Carburetor
A dirty carburetor may be culpable if your John Deere lawn mower won’t stay running.
The carburetor in your mower is responsible for mixing air and fuel for combustion inside the tractor engine.
As such, it gets directly affected by old fuel in the tank. Over time, the sludge, sediments, and gums from the old fuel can clog the carburetor’s fuel jets, inhibiting its performance.
This can prevent your John Deere mowing tractor from staying running.
How to diagnose and fix the problem
Start by removing the air filter from its housing and spraying it with carburetor cleaner to free the air intake.
Next, start the mower and observe if it works. If it stops soon after starting to run, you must clean the carburetor, starting by taking it apart.
While cleaning a carburetor is not a complicated process, it takes some elbow grease and attention to detail because you will be taking apart several mechanical components.
Alternatively, hire a professional or take the carburetor to a lawn mower repair specialist for cleaning.
The ultimate option is to install a new carburetor. But this should only be necessary if a professional diagnosis determines that the old one is unserviceable.
5. Broken or Blocked Cooling Fins
Your john Deere mower engine has cooling fins next to the spark plug. The fins milled into the mower’s exterior frame create a larger surface area through which heat from the engine is dispersed into the atmosphere.
However, debris, including grass clippings, can lodge between these cooling fins, blanketing their interior and preventing the desired airflow.
The result is an overheating engine that can shut down as a failsafe.
How to fix the problem
Check the fins for any broken pieces or debris trapped in them. Once you locate such debris, clean the fins to restore the air filter to its proper working condition.
If you see any broken fins, replace them to resolve the issue.
6. Dirty or Damaged Spark Plug
The spark plug may be a tiny component, but one of the most crucial, responsible for the starting and running of our mower’s engine.
This component produces the electric spark that ignites the engine’s combustion. They literally ignite the engine, bringing its pistons into motion, and start the vehicle.
Therefore, a dirty or faulty spark plug will not produce the required bold of electricity, making it a key culprit when the John Deere lawn mower stalls after starting.
In these cases, the component may have produced enough spark to start the engine but not enough to sustain the motion.
What to do
Pull out the spark plug from its place and inspect it. You will know if it is dirty by noticing the buildup of carbon on it.
Try to clean the buildup and test if the mower works again. If it doesn’t, you may have to replace the spark plug to restore normal functioning.
You also want to ensure the cables connecting the component are secure before replacing it altogether.
7. Too much Oil in the Mower Engine’s Crankcase
Overfilling the engine’s crankcase with oil increases the buildup of pressure in it during its operation.
Such a thing can result in overheating that eventually causes the mower to shut down prematurely.
The overfilled crankcase can also let some oil into the cylinder via the component’s valve train. This leads to oil combustion, with the smoke produced clogging the air filter.
In other words, the mower will be choking with smoke, causing it not to breathe properly, resulting in a shutdown.
What to do
The solution is to correct the engine oil level by draining out the excess from your crankcase.
Use the oil dipstick to tell when the correct oil level has been reached. This should be between the two lines on the dipstick.
8. Dirty Air Filter
The engine on your John Deere tractor, like any vehicle, uses oxygen from the air for combustion. This means the engine won’t run without access to oxygen.
A dirty air filter has clogged fins that limit air circulation, limiting the amount of oxygen the engine receives.
With limited access to fresh air, the engine will struggle to run and eventually die, shutting off your John Deere lawnmower.
Inspecting the unit’s air filter and cleaning it frequently can prevent this problem. But if it strikes, below is a possible fix.
What to do
Clean the paper filter element on the affected tractor. Start by carefully removing the dirty air filter from its housing.
Find a solid surface and tap the filter against it, knocking out the dirt. Once all the dirt particles have fallen off, hold the filter against light to check if the blockage has come off.
Finally, remove any dirt in the air filter housing before replacing it to avoid recontamination.
If light does not pass through the filter after knocking out the dirt, you will not be able to reuse it. Instead, get a new air filter to replace it.
9. A Damaged Ignition Coil
The ignition coil converts the battery current into more powerful energy, enough to ignite the fuel and power the engine.
If this coil is damaged, it will likely short out instead of getting the required voltage. So if your John Deere mower quits when hot, it may indicate a bad ignition coil.
We recommend using an Ohmmeter to measure the electrical resistance from the coil and identify the damaged one. The bad ignition coil will show a break—replace it to fix the problem.
10. Clogged Gas Cap Vent
Sometimes John Deere tractor keeps stalling due to a bad or clogged gas cap vent.
This blockage inhibits the fuel cap vent’s ability to allow air through. As a result, the vehicle’s gas tank experiences a vacuum that restricts fuel. This is a common problem with John Deere f725.
What to do
Troubleshoot the problem by loosening or removing the suspect fuel cap and starting the engine. If the mower runs without stopping, the fuel cap is bad.
Replace it to fix the problem.
11. Wrong Position of the Choke
The choke helps with cold starting the engine, starting after sitting without working for a while.
This component must be positioned correctly to restrict the airflow and let more gas into the engine’s combustion chamber before it heats up.
Leaving the choke on after the engine has heated up makes it restricts airflow to the engine when the latter needs it. That restricted airflow fatigues the engine, forcing it to shut down.
Reposition the choke to allow normal air circulation to the engine.
12. Low Fuel
While your vehicle may fail to start if the fuel is low, it sometimes does start. But the insufficient gas will not sustain the engine, leading to a shutdown.
What to do
The solution for low fuel is a no-brainer: check the fuel and refill it if the vehicle has little.
13. Fuel Shut-off Solenoid Malfunction
The fuel solenoid is responsible for directing fuel flow to the engine to enable it to run or stop.
If this part fails to function correctly, it can stop the flow of fuel to your mower engine when you want it to allow it.
Such malfunction will cause the engine to die unexpectedly. So if your John Deere diesel tractor starts and then dies, this component might be responsible.
To resolve this problem, replace the malfunctioning fuel-shutoff solenoid with a good one.
Why John Deere tractor starts and then dies?
Your John Deere Tractor may start and then die due to fuel issues. This problem occurs when the tractor’s engine does not get enough fuel as a result of a fuel delivery issue.
Why does John Deere stall after 20 minutes?
John Deere lawnmowers can stall after 20 minutes of operation due to restricted distribution and rate of fuel and airflow in their respective systems. The restriction can result from clogging or blockage of hoses and air filters involved.
Final Thoughts on Why the John Deere Tractor Keeps Shutting Off
Several factors can cause a John Deere lawnmower to keep shutting off after starting. However, each of these problems is preventable if you perform regular routine maintenance on the mowing tractor.
Nevertheless, if something slips through the cracks and causes your mower to die soon after starting, consider using the solutions suggested in this write-up to diagnose and fix the problem.
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