John Deere Tractor Turns Over But Won’t Start: Reasons & Solutions

The engine is a vital aspect of your John Deere tractor. It’s the heart of your tractor and without it, your John Deere won’t move forward and backward. If your John Deere tractor turns over but won’t start, you need to check on the engine.

However, even though it won’t start, there could be potential problems with the engine. However, it doesn’t mean that you need to replace it. A simple change can be sufficient.

Keep reading as we explore the reasons and steps to take when the tractor turns over but cannot start.

Why John Deere Diesel Tractor Turns Over But Won’t Start?

John Deere tractor turns over but won't start

Let’s check all the possible reasons first. Finding the reason accurately will help us to fix it. Here are 11 possible reasons:

  1. Problems with The Fuel Filter

Have you checked the fuel filter? A clogged filter is the number one reason that can cause your John Deere tractor not to start.

Therefore, you can inspect the fuel filter as dirt can clog the ducts and block the fuel from proceeding to the engine.

If this is the case, remove the filter and clean it. If it’s damaged, then you need to have it replaced. Also, check if the fuel lines are clogged and get rid of the dirt.

  1. Poor Quality of The Fuel or Diesel

If your John Deere diesel tractor fails to start, maybe the quality of the fuel is poor. If the fuel overstays in the tank, residue may settle at the bottom which affects its quality.

Empty the fuel completely and clear the residue from the tank. In the future, it’s recommended to use fuel brands with an additive to prevent this problem.

  1. A Faulty Or Clogged Fuel Cap

A faulty fuel cap is a probable reason why a tractor may fail to start. First of all, the tap must remain open all the time and when it’s closed, it affects the normal fuel and circulation of the engine.

You can run a simple procedure to the test plug.  Start by opening the cap and if fuel does not drain, it means there is some residue that you must clean.

Additionally, clear the dirt while ensuring the valve remains open. Learn more about valve adjustment of a tractor.

You may notice fumes coming out of the cylinders which can be due to a clog on the fuel cap and this creates a vacuum.

It can cause the tractor not to start and you can fix this by cleaning the cap or replacing it.

  1. Insufficient Power From The Battery

An interruption in the power supply can occur and it’s important to troubleshoot the tank. A dead battery could be the reason your tractor fails to start.

Often, it will respond with an audible click but cannot start. You can do a simple test to check whether the batteries are functioning.

Start by removing the (-) cap followed by the (+) cap. Put a small amount of baking soda in a bowl of water and clean the posts. The advantage of this mixture is that it’s abrasive and will get rid of the chemical agent on the caps.

Before you start this test, ensure the terminals are dry before reattaching the caps, start with the (+) then, (-).  Finally, restart the engine.

If it doesn’t work, then the battery is dead and there’s a need to replace it. If your battery shows early signs of swelling, bloating, and leaking, then it’s dead and requires urgent replacement.

If you’re not able to make correct diagnoses, you can take the battery to a mechanic for further tests.

  1. Check whether your tank is full

fixing a Deere diesel tractor

It may seem obvious, but another reason your tractor may not start is the possibility of an empty tank.  The first thing is to check the fuel level of the tank. If it is low, then you need to have it refilled.

If it doesn’t start, you may need to prime the engine and increase the pressure of your tank. The process involves removing air pressure stuck in the fuel lines.

You can use the built-in primer pump in your tractor’s engine.  Keep pumping every ten minutes to remove the air and pressurize the fuel in the tank.

Restart the engine and if it still can’t start, try again after a few minutes.

  1. Check for fuel contamination

Fuel contamination can be the reason the tractor won’t start. You can check whether there is any gasoline contamination by simply smelling.

If there is any trace of contamination, flush the fuel tank and refill it with clean diesel fuel.

The next step is to check the fuel for contamination with microbes such as bacteria and fungi that come in through the water. Flush the fuel and refill the tank.

  1. Interference From considering External Elements

During cold weather such as winter, the tractor’s engine may fail to start. The reason being, the low temperature can cause the oil to thicken.

After that, the engine fails to compress in the cylinders, and subsequently, the tractor won’t start.

Check whether the oil is gunky and replace it with a winterized option.

The cold can lower the output of the battery. Subsequently, the amps may fail to power the tractor’s engine. The quick solution to solve this problem is to jumpstart the engine to power it.

Diesel fuel can turn into wax crystals during winter, and this can cause a blockage. Warm the garage to heat the fuel and dissolve the crystals. Lastly, attempt to start the engine.

  1. A Faulty Hose

If your John Deere diesel tractor turns over but won’t start, you need to check the hose. Start by disconnecting the hose from the fuel tank and check whether there’s leakage.

If fuel doesn’t flow, it means there’s a blockage; you’ll need to replace the hose.

  1. Air In The Fuel Lines

Your tractor engine requires air compression and fuel to run. Air in the fuel lines can lower the pressure in the engine and restrict the proper flow of fuel to the engine. Bleeding the air from the system will eliminate this problem.

Start by turning off the valve and clean the fuel filter. Then install gaskets and properly secure them. Allow the fuel to flow and locate the prime pump.

Next, pump to release the air from the bleed plug. Repeat the process in all the bleed plugs and finally close. Try to restart the engine and, if it fails, repeat the process.

  1. A Problem with The Fuel Injection Pump

A fuel injection pump is an essential component of your tractor’s engine system. A problem with this system will cause the engine not to access airflow or get fuel from the tank.

Therefore, this prevents the tractor from starting and even if it starts, it may stall along the way. When this happens, it’s vital to consult an expert as repairing the fuel injection pump is complex.

  1. Broken Engine and Faulty Glow Plugs

If your tractor engine is completely broken, there may be no DIY solution. You can hire a mechanic for a full diagnosis who may recommend a replacement or repair.

Glow plugs are essential parts in your tractor’s engine that heat and allow the fuel to ignite the engine. Some tractors have over ten glow plugs and if three fail, the engine may fail to ignite.

You can check if the plugs are working by disconnecting the wires and using a test light.

If the device lights up, it means the plug is in excellent condition, but if it fails, then it’s faulty and needs urgent replacement. Now, watch this video to diagnose your John Deere tractor yourself.

Conclusion

There are many reasons your John Deere tractor turns over but won’t start. Some simple quick fixes are easy and you can do it yourself without incurring the expense of hiring a professional.

For instance, cleaning dirty or clogged filters and emptying the fuel pump. However, repairing a damaged fuel injector pump is complicated.

If the above solutions don’t solve the problem, there is a need to call an expert for a complete diagnosis.

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