5 Common John Deere 4850 Problems and Fixes

Do you have a malfunctioning John Deere 4850? Need solutions from a dependable source but can’t find a way? Fortunately, this article covers all the common issues, so you won’t have to worry.

A common problem with the John Deere 4850 is the power shifting stop. There is also the possibility of the engine not starting on this tractor. Slow starter speed is also a common problem with John Deere 4850 tractors. The John Deere 4850 is prone to metal shavings problems.

Well, this is just an overview. The elaboration is here.

John Deere 4850 Engine Problems: Solved

John Deere 4850 Engine Problems
Source: Machinerypete

There are some probable problems with the engine of the John Deere 4850. Let’s take a look at those problems at a glance.

Problem Reason Solution
Engine won’t turn Drained/ Dead battery Jumpstart/replace the battery.
Ignition switch failure Replace the ignition switch.
Engine overheating Fan hub failure Replace the fan hub.
Contaminated fuel Clean Fuel Filter and Refuel.

Now let’s elaborately discuss these problems for a better understanding.

Problem 1: The Engine Won’t Turn

You may face problems like not starting with your John Deere 4850. It may be caused by different reasons. Let’s see what they are.

Reason 1: Drained/ Dead Battery

A drained or dead battery might cause your John Deere 4850 engine not to start.

Your vehicle is powered by a chemical reaction: your battery produces voltage to start your vehicle by converting chemical energy into electrical energy.

A drained or dead battery can’t provide the necessary voltage to start the engine. And that’s why a drained or dead battery is the reason behind the engine not starting.

Solution: Jumpstart or Replace Battery

Jump-starting your John Deere battery is the only solution if your battery is drained. It is not difficult to jump-start your John Deere 4850 on your own.

However, you’ll need a few supplies first. The first thing you’ll need is a set of jumper wires. A second requirement is the help of a fellow motorist. The third thing you’ll need is another vehicle with a charged battery.

  • Make sure both vehicles are facing each other when parking. Make sure you use the parking brake to ensure your safety.
  • Find the batteries inside both hoods. If necessary, remove the plastic hood.
  • You must locate the battery’s positive and negative connections. Check that they are not corroded.
  • The red clamp must be connected to the dead battery’s positive terminal.
  • Connect the other red clamp to the positive post of the functional battery.
  • Similarly, the black clamp should be connected to the negative post of the functional battery.
  • The last black clamp should be connected to the unpainted metal surface of your car.
  • Now, start your engine and see if it works.

If your battery is dead, there is no solution except to replace it. It’ll cost around $230 to $400.

Reason 2: Ignition Switch Failure

An engine’s ignition is the key to starting it. An ignition defect can cause a not starting problem. Because when you jiggle the ignition key, it makes a spark in the engine, which creates a force then the engine gets started.

So, your John Deere may not start for a defective ignitor.

Solution: Replace the Ignition Switch

The best solution for a defective ignition switch is to replace it. It’ll cost $42 to $50.

Problem 2: Engine Overheating

John Deere 4850 Engine Overheating
Source: Quora

We’ve often found a few cases where the John Deere 4850 faces an engine overheating issue. However, it’s common for all types of engines.

The engine can overheat due to different reasons. See what’s causing the engine to overheat.

Reason 1: Fan Hub Failed

One of the key components for keeping the John Deere engine cool is the fan hub. It controls the overall cooling system. There is a high chance that the engine would overheat if it got damaged.

Solution: Replace Fan Hub/ Contact Technician

Solution for a damaged fan hub is replacing the hub. Because the whole hub system is pretty complicated, you can also call for a service to fix your John Deere 4850 fan hub.

Reason 2: Contaminated Fuel

The engine can overheat most of the time if the fuel is contaminated. Contaminated fuel causes a blockage in the fuel filter. Therefore, the cooling system cannot function properly.

Due to its inability to reach the engine, Mobil cannot control overheating. Overheating of engines is a result of this.

Solution: Clean Fuel Filter and Refuel

The only way to solve this problem is to remove the bad fuel and refuel with refined fuel. Using a filter when fueling your John Deere is always a good idea.

John Deere 4850 Fuel Problems: Solved

Fuel is another major issue with the John Deere 4850. There are different types of issues with fuel.

Problem Reason Solution
Slow starter speed Air leakage to the fuel inlet Pump fuel unit to run air out.
Metal shaving Improper lubrication and friction between metal parts Use an automatic conveyor and filtered lubricants.

Problem 1: Slow Starter Speed

Slow starter speed is a problem that can happen in John Deere 4850. We’ve noticed this type of problem in various models of John Deere.

For multiple reasons, a slow starter speed can cause. But here we’ll discuss the possible reason for the John Deere 4850 slow starter speed.

Reason: Air leak to the Fuel in lent

An engine with an air leak may run normally but idle faster, unevenly, misfire, hesitate, or stall.

You may notice that your car doesn’t accelerate as well as it usually does. A significant amount of air leakage may prevent the engine from starting at all.

Solution: Pump Fuel With a Fuel Pressure Gauge

The issue of air in the fuel inlet can be resolved by pumping fuel into the fuel pump with a gauge. It is very simple to do. Pump into the fuel inlet until all the air has been expelled.

Problem 2: Metal Shavings

Metal shavings are the chippings, flakes, or microscopic metal particles that can be found in motor oil.

It is usually caused by oil pollution or friction and wears in the engine’s working parts. There are several other reasons behind it. We’ll discuss that here.

Reason: Improper Lubrication and Friction Between Metal Parts

Lubricant circulates through and around several moving components in your car.

Considering the speed of these moving parts and the length of time you run your engine, some metal is likely to chip off. And this factor causes metal shaving.

Solution: Use an Automatic Conveyor and Filtered Lubricants

By using a conveyor, separating the metal shaving from the lubricant is very simple. It’ll scrap all the shavings from the engine. You may need the help of an automotive professional to do this.

John Deere 4850 Throttle Problems: Solved

Problem Reason Solution
Powershifting stop Contamination in transmission fluid Change the fluid.

Problem 1: Powershifting Stop

The power shifting technique, also known as full-throttle shifting or flat-shifting, is a manual gearbox shifting technique that minimizes the time the wheels are not being driven.

However, the power shifting of John Deere 4850 can stop for a certain reason. Let’s see what that is.

Reason: Contamination in the Transmission Fluid

The main reason behind the power shifting stops is contamination in the transmission fluid.

Fluid works for smooth transmission of the power-shifting throttle. But the contamination hampers the smooth transmission.

And this is the reason why the power shifting stopped working.

Solution: Change the Fluid

The only solution for stopping John Deere 4850 power shifting is changing the transmission fluid. Besides changing the transmission fluid, ensure you are careful about preventing contamination.


What Motor Does A John Deere 4850 Have?

The John Deere 4850 has an intercooler turbocharged diesel 6-cylinder engine. This tractor has a maximum horsepower of 205. The expected RPM is 2200. This engine is estimated to have a displacement of 466 cubic inches. In addition, there is a 32-quart capacity for coolant.

What Is the Highest Horsepower Tractor John Deere Makes?

The John Deere 9RX 640 is the largest and most powerful 4-track tractor of John Deere. The maximum horsepower of this tractor is 691. Aside from that, it is a giant tractor. Almost 56981 pounds make up the weight of this tractor. Moreover, it is capable of carrying out any type of heavy task.

What Hp Tractor Do I Need for 10 Acres?

When you need to mow 10 acres and perform other minor tasks, you will need a tractor with 30-60 horsepower. The increased horsepower and torque reserve make it possible to transmit more power to larger and heavier implements and attachments.


Well, this was all about the John Deere 4850 problems. You have been informed about all the possible issues you may encounter with your John Deere 4850 tractor.

Nevertheless, better maintenance can prevent any damage and problems. For a problem-free tractor operation, make sure your tractor is well maintained.


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