John Deere Mower Won’t Work

The John Deere brand is one of the most recommended options when the topic is about mowers. However, the brand’s positive reputation doesn’t mean that the machines will always run without a hitch. On the contrary, you are bound to find problems with the mower from time to time.

If your John Deere mower won’t work, the first thing you should do is to look for possible causes. For instance, the reason why the mower stops once hot will be different from why the blades won’t engage. Troubleshoot the simpler problems, but leave the more technical ones to service technicians.

The rest of the article will look at some of the most common reasons why a John Deere mower won’t work, and possible solutions for them.

John Deere Mower Stalls When PTO Engaged

The power takeoff (PTO) on your mower should transfer power to the blades once it’s engaged. If your mower stalls when it is engaged, it could be as a result of any of the two problems discussed below.

Electrical Problem With the Rectifier

The rectifier is an important electrical part that houses diodes. If the internal ground connection is broken, the rectifier won’t be able to communicate with the alternator in your lawn mower properly to produce the amps needed to run the blades. 

You can deal with this problem by running a wire from one of the screws holding the rectifier to the engine block, and then ground the other end of the wire to the frame. Once you reestablish the ground connection, the mower should work fine.

Pulley Not Spinning Freely

If a pulley in your John Deere mower isn’t spinning freely, the engine will stall when the blades are engaged. To confirm that the pulleys aren’t causing your John Deere mower to stall when engaged, you need to check for damage and sticking. Here are the steps to do this:

  1. Remove the drive belt from the engine pulley.
  2. Lift the lever to engage the blades.
  3. Engage the deck level to release the blade brakes.
  4. Spin the idler pulleys found on the mower deck.

If the pulleys growl while turning or don’t move at all, you have to get them replaced. The major tool you’ll need is a wrench of the proper size. Here’s a video on how to do this:

John Deere Mower Quits When Hot

As is the case with other brands, your John Deere mower engine needs the right mix of air, fuel, and ignition spark to function properly.  

While most people know about the need to ensure a proper fitting plug and use the right fuel, the possibility of overheating is largely ignored. The heat generated as the gas burns inside the cylinder needs to be cycled out properly, or the engine will stop working.

Here are some of the reasons why your John Deere mower quits when hot and what you can do about it.

Vapor Lock Problem

Vapor lock refers to when the heated gases inside the fuel tank released enough. The built-up pressure will reverse the gas flow, pushing it out of the carburetor. This shuts down the engine.

The main cause of this problem is a grimy fuel tank cap. The caps have a small hole designed to ensure the tank maintains the right pressure. Cleaning or replacing the fuel cap will solve this problem.

Inadequate Spark

When the spark plug is bad, the mower may not start up in the first place. However, there are some cases where it is just good enough to allow some minutes of operation. Once the mower runs for a while, the heat will worsen a problem in the plug. 

In some cases, you’ll find that the gap between the center electrode and the ground electrode (the curved metal at the top) on the spark plug is far too big or too small. Adjusting the gap by slightly pushing the ground electrode downwards or upwards can solve this problem.

If the spark plug housing is cracked, you need a spark plug made for your John Deere mower.

Fuel Supply Problems

If there are problems with the fuel supply, the engine on your John Deere mower will shut down after it heats up considerably. You need to check the fuel supply before you start using it. Fuel older than a month will develop some sticky substance that will clog up the system if you try to use it.

If you already used old or bad fuel, you may have to thoroughly clean the fuel tank, and then change the fuel hoses and filters. Simply using fresh fuel in the hopes that it will clean out the system won’t be enough. You should also clean the carburetor thoroughly to get rid of any deposits from the bad fuel.

Don’t forget to check the oil supply. Top-up the oil when necessary, and change it completely after every 25 hours of using the mower.

Air Filter Problems

The mower can also shut off when it gets hot if it can’t get enough air to keep powering combustion. The air comes in through the air filter and goes out through the muffler. Unfortunately, the air filter in any mower, including John Deer products, will get dirty quickly. So, you should clean it after every eight hours of use.

The muffler, on the other hand, can go up to 60 hours before it needs cleaning. If any of these parts are too dirty to clean, you should consider changing them completely.

John Deere Lawn Mower Blades Will Not Engage

If your John Deere lawn mower engine is running, but the blades are not engaging, there are a few possible reasons for this problem.

Drive Belt Issues

The power takeoff (PTO) mechanism and the drive belt on your mower work together to engage and disengage the mower’s blades. The mower blades will not engage if the belt is worn or damaged. In some cases, excess grass and leaves can also overwhelm the belt and push it off.

Changing the belt or remounting it can get the blades working again. However, you need to ensure that the blades are installed correctly.

A Frozen Idler Pulley

The idler pulley on your mower is responsible for adjusting the tension in the drive belt, which gets the blades working. If the pulley is frozen and doesn’t rotate, the blades won’t either. Once you change the idler pulley, the blades will start working again.

Weak Battery

Some more recent John Deere lawn mowers come equipped with an electric PTO, which relies on the battery on the mower to work. If the battery is dead or not properly charged, the PTO mechanism to power the blades won’t be triggered. Charging the battery can solve this problem, but if your battery can no longer hold a charge, you’ll have to replace it with a new one.

Obstructions in the PTO

Rocks, plastics, wood, or other such objects can get lodged in the mower’s PTO system. Once this happens, the PTO won’t function, which leads to unresponsive blades. Check the system for any possible obstructions and remove them.

Don’t know where to look? Check the manual that came with your lawn mower for a picture. If the object has damaged the PTO knob, you’ll have to get a new one.

Note: Please ensure the mower is turned off before troubleshooting the blades. If it comes on suddenly while you are working on it, there is the risk of injury.

John Deere Riding Mower Stopped Running

If your John Deer riding mower stopped running midway, it could be a result of any of the common problems that can stop an engine from running.

Old Gas

Most riding John Deere lawn mowers come with 4-stroke engines, but they are still not immune to the effects of using old gas. Ethanol-based gas sitting in your garden for months will most likely have absorbed water. Using this will lead to engine malfunctions and will damage parts of the engine over time.

Carburetor Problems

The carburetor is always very busy when your lawn mower is running, making it prone to damage. Fortunately, repairing and replacing one of these is straightforward. The most common problems that can make a carburetor fail in its combustion-related duties are impurities and cracks to the casing.

Does the riding lawn mower stop running when you increase the throttle? It could be dirty or clogged. Use a cleaning spray for carburetors to get it working optimally again. Don’t know how? Here’s a video that can help:

If your carburetor isn’t dirty, but you can find cracks and ruptures, you’ll have to get a new one. You can also adjust the carburetor to regulate the amount of air and fuel entering the engine.

Filter Problems

The fuel filter ensures that the residue from the gas tank won’t enter the engine. Over time, it will become clogged, preventing adequate fuel from reaching the engine while running, especially when you increase the throttle. Once this happens, the engine will shut down.

A dirty air filter will also lead to your lawnmower engine dying once you increase the throttle. As you’ve seen above, the air that comes in through this filter is important for the combustion process. Cleaning or replacing the air filter will ensure that dust and debris aren’t making your lawn mower shut down in the middle of a session.

Dirty Spark Plug

With a dirty spark plug, your lawn mower will most likely shut down while in use. You should change your spark plug once a year. If it’s been a while since you changed it, and you need to use your lawn mower right away, you can consider cleaning it.

John Deere Riding Mower Keeps Stalling

If your John Deere riding mower keeps stalling, the problem could be addressed with some of the fixes we have already discussed above. Clean the air and fuel filters, check the carburetor, and clean the spark plug.

If the mower only stalls when you are going uphill, you should consider changing the fuel pump. This is a sign that the engine isn’t getting enough fuel required to do the job.

Why Is My John Deere Mower Not Starting?

Most of the reasons that can make a John Deere mower stop running when in use can also prevent it from starting up in the first place.

The spark plug is responsible for igniting the air and fuel mixture in the engine’s cylinder. Once it is damaged or too dirty, the combustion process can’t be completed. Clean the spark plug or change it to get the engine running again.

While the spark plug is usually the first port of call in this situation, other factors such as having old or bad gas in your engine and having clogged carburetor, air, and fuel filters can also stop the lawn mower from working.

The sediment from an old gas can damage engine parts like these. If you haven’t cleaned out any of these parts before now, they can prevent your John Deere mower from starting. When cleaning or changing the parts, you should start by draining the old gas from the fuel tank and replacing it with fresh gas.

How to Start a John Deere Push Lawn Mower

To start a John Deere push lawn mower, here’s what you should do:

  1. Move it to an open, grassy area and get rid of small objects that can impede its movement.
  2. Check to ensure there’s enough gas and oil in the mower. With 2-stroke engines, you’ll have to mix oil in the gas.
  3. Check the spark plug to be sure it is firmly attached and correctly capped with the rubber cover. If the mower is old or has not been in use for a while, you may have to change the spark plugs.
  4. Prime the carburetor by pushing the red or black button on the mower’s body three to four times to get some gasoline into its system. If you have a model that doesn’t have this system, you can skip it.
  5. Open the throttle by putting in a mid-to-high position to ensure the engine will keep running once you’ve started it.
  6. Set the choke to ensure a better fuel-air mixture in the engine and make it easier to start the engine.
  7. Pull the starter cord upward. You’ll need to do it firmly and quickly. With the choke turned on, you shouldn’t have to pull the cord more than three times. Once the engine comes on, you can return the choke to normal.

If your John Deere push mower doesn’t start after following this process, and you’re sure you have enough gas in the compartment, check the spark plug and try again.

How to Move a John Deere Lawn Mower

Moving a John Deer lawn mower is a straightforward process. Your focus should be on keeping the mower and all its parts intact during the move and also prevent any accidents. Here’s what you should do:

  • Drain the gas and oil. These liquids are rightly treated as hazardous materials when moving property. Gas exposed to heat in the back of a moving van can cause a fire. Oil leaks can ruin everything else in the van as well.
  • Clean the lawn mower properly. Get rid of all dirt and grass in the wheels and undercarriage of the lawn mower to ensure other items in the van don’t get dirty.
  • Get rid of all blades and attachments. Apart from the fact that the blades can get damaged in transit, removing them also prevents the risk of an accidental cut. Wear thick gloves when removing the blades and make sure they are properly stored in a box.
  • Disengage the spark plug. This is to ensure it doesn’t accidentally come on while it’s in transit. Even without gas, the residue in the carburetor can still be enough to get it working. The risk of this happening with lawn mowers that have a starter cord only is minimal, but it’s a good idea to avoid any risks.
  • Move the mower and parts to the moving truck. You’ll need a ramp to move the lawn mower onto the truck. Some push mower models can be lifted without a ramp if you have some help, but don’t attempt to force the process as you’d risk bodily injuries and damage to the mower.
  • Secure the mower. A moving blanket and some tape are enough to secure a push mower in the back of a van. For riding mowers, you’ll need to use tie-down straps to hold it in place.

Final Thoughts

If your John Deere mower doesn’t work, you could get it working again in no time with some but of troubleshooting. We have looked at some of the most common complaints above. If you are dealing with one of these problems, follow the solutions recommended to resolve the problem.

If you are unsure about completing the troubleshooting on your own, you can enlist the help of a technician who has experience working with John Deere mowers. They could charge up to $100 to resolve issues like clogged air or fuel filter, but it is a better option than risking more damage to the machine by going the DIY route.

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