Fixing Common Issues of John Deere Mower

A John Deere lawn mower may turn over but fail to start if it does not have the requisite air, gasoline, and spark to initiate combustion.

There are a number of potential reasons why a John Deere lawnmower won’t start after being turned over, including a clogged fuel line, a stuck choke, a dirty carburetor, a faulty fuel pump, a blocked fuel tank vent, or a dirty spark plug.

Always use caution and follow the instructions in the manual. The spark plug wire must be disconnected before any maintenance can be done.

Plugged John Deere mower air filter

Be sure to read and understand the operator’s manual before attempting any diagnosis, repairs, or use of the equipment. Seek the help of a professional if you doubt your ability to make the repair properly due to a lack of experience, training, or health.

9 Causes John Deere Mower Fails to Ignite

John Deere Lawnmower Has a Stuck Choke or Is Set to the Wrong Position

First, make sure the choke is set properly. The choke is used to restrict airflow. This is what you use to fire up a chilly engine. When starting a warm engine, you don’t need to use the choke.

If you have the choke lever set incorrectly, your John Deere may have trouble starting or refuse to start altogether.

The answer is to remove the choke before trying to start a warm engine. The choke must be engaged for a cold engine to start.

Once the engine has warmed up, you can disengage the choke by moving the lever to the “off” position. If this isn’t adjusted, the mower will turn off.

If the choke is adjusted correctly but airflow issues persist, verify that the plate is not stuck and the cable can be moved easily. Carburetor cleaning can be used to help free a clogged choke plate and linkages.

To replace a frayed or worn John Deere choke cable, you’ll need a whole new cable.

A John Deere Lawnmower with a Clogged Air Filter

The next step is to examine the filter. This is another potential airflow blockage for the mower.

The air filter serves to filter out particles and dirt before they may enter the engine’s air intake and cause damage.

The filter can become so dirty that it prevents enough air from passing through if it isn’t cleaned or replaced regularly.

I suggest getting a new filter at the start of each mowing season and cleaning it multiple times during. Mower blades may need to be changed more regularly if you operate in extremely dusty environments.

The following are cleaning instructions for a John Deere paper air filter and foam pre-cleaner, which may be required by your engine.

If you want to know what kind of filter your mower has or how to clean it, you should look in the handbook.

Cleanse a John Deere Mower Paper Air Filter

  • Get rid of the filter from the air housing. Please ensure that the air intake remains clean.
  • Use a clean, dry rag to wipe out the air filter housing and remove any remaining dirt or debris.
  • Tap the paper air filter against a hard surface to remove as much dust as possible.
  • Hold the paper filter up to a light to see if any light is passing through it.
  • Filters should be reused wherever possible.
  • You should get a new filter if the old one is damaged, excessively dusty, or not letting in any light at all.
  • Reconnect the air filter cover. If your push mower has a foam pre-filter, follow these steps to clean it and install it before putting the filter cover on.

How to Maintain a John Deere Mower’s Foam Pre-Filter. The pre-filters employed by various engines vary.

You can’t compare this to a standard foam filter. Foam pre-filters are often used in conjunction with standard paper air filters to further reduce dust and debris intake. Oil put to a pre-filter will damage the paper filter.

  • Check out the pre-filter. You should get a new one if you find any tears or if it seems brittle.
  • Wash the foam filter with water and mild dish soap to remove grease and grime.
  • Soap residue can be removed by giving the water a good rinse.
  • Flatten out and dry in the air. If you leave the filter out in the sun, the drying process will move much more swiftly.
  • Once the foam pre-filter and paper primary filter have dried, install them.

John Deere Lawnmower with a Filthy Spark Plug

If you think you might not have enough air, check for a spark. To take out the spark plug, use a 3/4″ or 5/8″ socket wrench. The size you need is dependent on the make and model of your engine.

If your mower’s spark plug is dirty or broken, it may be difficult to get it started and keep it running.

Check the spark plug with a quality tester. If you find that the spark plug is significantly rusted or unclean, you should replace it with a new one.

If the spark plug is otherwise in good shape but slightly filthy, you can attempt to clean it. A little wire brush helps eliminate the carbon accumulation.

Once you have confirmed the correct electrode gap, the spark plug can be replaced. After that, you’ll secure the spark plug wire.

A healthy spark plug is essential for a lawn mower to perform at its optimum, so I recommend replacing it at the beginning of each season.

Using Antiquated Gasoline in a John Deere Mower

Don’t let the gas sit in your John Deere tractor for too long. Old gas can limit fuel flow and damage parts due to varnish and sticky deposits.

If you want to make sure you’re using the right gas in your John Deere lawn mower, you should always buy fresh gas and use it within 30 days. Any gas that contains ethanol should be avoided.

All 4-cycle lawn mowers require fuel with an octane value of at least 87 and no more than 10% ethanol. Some manual lawn mowers have a 2-cycle engine, which is an older design.

See for further details on how to choose the right fuel for a 2-cycle or 4-cycle engine. This is the fuel for a John Deere mower.

If you find that the fuel in your John Deere is stale, drain it using a fuel siphon pump.

By adding new gas and a fuel stabilizer like Sea Foam to the tank, you may assist eliminate moisture buildup and clean the fuel system. The benefits of sea foam are discussed in greater detail here.

In order to ensure that the treated fuel is distributed throughout the fuel system, start the mower and let it run for 10 to 15 minutes after refueling. If you haven’t found the underlying source of the problem by this point, continue working your way down the list.

John Deere Lawnmower Fuel Filter Clogged

The gasoline filter cleans the fuel as it leaves the fuel tank, preventing any debris from following it into the fuel system. The engine and fuel system won’t suffer as much wear this way.

Filters can become clogged if they aren’t changed regularly. Because of this, fuel won’t be able to reach the filter effectively. If the mower runs out of gas, it could stall and turn over.

The solution is to get a new gasoline filter if the old one is clogged or broken.

John Deere Lawnmower Fuel Line Clogged

Check the gasoline line for any kinks that could prevent fuel from flowing freely. The next step is to check the pipeline for any fuel restrictions that may have developed.

As I indicated before, sludge-like deposits left behind by old gas might choke the fuel line. This will narrow the entrance and make it harder for fuel to flow into the carburetor.

Checking for a fuel limitation in the fuel line requires turning off the gasoline supply, either using the fuel shut-off valve or fuel pinch-off pliers. You should disconnect the fuel line from the lawnmower’s fuel pump if it has one, or from the carburetor if it doesn’t.

After placing the hose’s end in the storage unit, fuel delivery should be restarted. Since gasoline cannot flow uphill without a pump, the storage container must be situated below the fuel tank. Monitor the water level in the container as it fills up from the pipe.

If there isn’t enough gas in the line, the problem can be fixed by cutting power to the mower and disconnecting the fuel line.

Carburetor cleaning can be sprayed into the line to remove the obstruction. By clearing the line with a blast of compressed air, the obstruction can be eliminated. Compressed air and carburetor cleaner should be used repeatedly until the obstruction is removed.

The fuel line should be reconnected once the blockage has been removed. If the fuel line is old and showing signs of cracking, or if the restriction cannot be removed, a new fuel line should be installed.

John Deere Lawnmower Has a Faulty Fuel Pump

A John Deere will employ a fuel pump if the carburetor is elevated above the fuel tank. The pump’s job is to overcome gravity by pumping fuel uphill to the carburetor.

Most mowers today run on fuel pumped using a suction system. This fuel pump draws fuel from the crankcase vacuum and sends it to the carburetor.

If the gasoline pump has any cracks or stops working, you will need to replace it. If no fuel leaks or cracks in the fuel pump’s exterior are visible, you can still take certain steps to assess its health.

Before attempting to test the pump, be sure fuel is reaching the inlet port. (If you aren’t, perhaps there is anything blocking the gasoline line or the fuel filter.)

The solution is to remove the fuel line from the carburetor and place it in a container after verifying that fuel is reaching the pump. Turn on the gas and the mower to see if the pump is working.

The gasoline line should have a steady or pulsating flow of fuel. If not, the gas pump should be changed.

If the John Deere has an electronic fuel injection pump, you can check the pressure with a fuel pressure gauge. Refer to the John Deere operator’s manual for specific information on fuel pressure requirements.

If the fuel pressures are below the threshold set by the engine manufacturer, a fuel pump replacement is required.

John Deere Lawn Mower with a Filthy Carburetor

The carburetor is the part of the engine that mixes fuel and air for combustion. If there is a problem with the carburetor, you will be unable to start your John Deere.

Too often, stale gas is the primary culprit when a carburetor stops performing. Fuel varnish can obstruct the fuel jet or cause internal parts to stick.

The carburetor can be fixed by cleaning it, replacing the broken pieces, or getting a new one.

Do this before you start dismantling your John Deere’s carburetor:

  • Make sure the carburetor is getting the gasoline it needs.
  • The air filter should be removed.
  • To begin mowing, spray carburetor cleaning into the mower’s air intake and then turn it on. If your carburetor starts to flip over and use the cleaner, it’s probably unclean. Poorly functioning engine oil
  • Once the carburetor has been dismantled, you can continue cleaning it or installing a new one.

John Deere Gas Cap with Blocked Fuel Vent

The gasoline tank must be evacuated in order to equalize the pressure inside it with the outside air. John Deere lawnmowers have a vent in the gas cap.

When the vent becomes blocked, no air can escape the fuel tank, creating a vacuum. This vacuum prevents gas from entering the carburetor. The lawnmower’s engine turns over, but it won’t start because it needs gas.

Loosen the gas cap and try starting the mower again to see if that resolves the problem. It could be that you forgot to replace the gas cap.

Keep the mower running while you tighten the cap to prove that it’s the cap and not the mower. If it sputters, turns off, and won’t turn back on unless the cap is removed, it has a problem.

Fix: swap out the faulty gas cap that’s blocking the tank’s air vents.

Are You Still Experiencing Issues with Your John Deere Mower?

As a John Deere owner, you will face a variety of problems throughout the mower’s lifetime. It may have trouble getting started, dying mid-mowing, vibrating excessively, cutting unevenly, or just not moving.

If you’re having problems with your John Deere mower, I wrote a handy tutorial to help you diagnose it. In this case, the book “Common John Deere Lawn Mower Problems and Solutions” is the best tool to use.