16 Common Causes Why Your John Deere Zero-Turn Mower Won’t Turn Over!

You, as a zero-turn mower owner, will inevitably face a day when your mower refuses to turn over.

If your John Deere zero-turn won’t turn over, check for a clogged fuel filter, clogged fuel line, dirty carburetor, defective gas cap, faulty spark plug, faulty starter solenoid, broken switch, dead battery, clogged air filter, or improperly adjusted choke.

Read on for some more beginner issues. Never attempt repairs without first removing the ignition key and spark plug wire.

What Can Cause a John Deere Not to Start:

  • Zero petrol in the tank.
  • Gas that is either old or incorrect
  • Caused by a clogged fuel filter
  • Due to a clogged gasoline line
  • Dull carburetor
  • Worn out gas cap
  • Broken gas pump
  • Air filter obstruction
  • Faulty solenoid that initiates the engine
  • Safety switch malfunction
  • Incorrect ignition switch
  • Lack of spark
  • Wiring, cables, and other parts that are loose or corroded
  • Having a weak or faulty battery
  • Incorrectly adjusted or jammed choke
  • Issues with the charging system

john deere mower

The Causes of a Dead John Deere Zero Turn Mower

John Deere Zero Turn Mower with No Gas

It’s possible that your fuel gauge is broken or that you’ve acquired a fuel leak, either of which could cause you to run out of gas sooner than usual. If you didn’t check the gasoline level before you began mowing, you could end up with an empty tank.

Just in case you didn’t think to check the fuel level before moving on to investigate the myriad of other potential causes of your John Deere’s starting trouble, let me remind you.

It’s a good idea to double-check the fuel system for any signs of a fuel leak. If a leak is discovered, it must be sealed or the damaged part must be replaced. Refuel the vehicle with new gas.

Using the Incorrect or Outdated Gas in a John Deere Zero Turn

Proper Fuel for a Zero-Turn Lawnmower by John Deere

It is crucial to use the correct gasoline and to maintain it fresh in order to keep the mower running smoothly. A John Deere zero-turn that runs poorly, won’t start, or stops working mid-use is generally due to old gas.

The majority of gas stations now sell fuel with ethanol. This fuel alternative is developed from plants, making it a more eco-friendly addition to gas.

The little engine in your John Deere is damaged by the moisture that ethanol pulls naturally to the fuel system.

The varnish left behind by the water and ethanol mixture prevents fuel from flowing freely and causes corrosion to mower parts, making it impossible to start the mower.

The engine and fuel system of a zero-turn vehicle are sensitive to ethanol, therefore it’s important to either use fuel with a very low ethanol content or none at all. High ethanol content gas is harmful to engines.

John Deere zero-turn mowers can only run on unleaded petrol with an octane value of 87 or above and no more than 10% ethanol.

When Operating a John Deere Zero Turn Mower, Only Use Fresh Gasoline.

It’s best to buy gas and use it up within 30 days, as after that point it starts to degrade and become less effective.

If you’ve bought more gas than you can use up in 30 days, you can extend its shelf life by using a gasoline stabilizer like Sea Foam Motor Treatment.

This is a fantastic item. All of my small engine products benefit from this extra layer of protection, so I put it into the fuel. Learn more about why adding Sea Foam to your gas tank is a good idea by reading on.

It is necessary to drain the gasoline tank if it is discovered that the wrong fuel was put in or if the fuel is old. Draining the tank is a breeze with the help of a manual siphon pump, which is both cheap and effective.

To clean the fuel system, eliminate moisture, and stabilize the gasoline, you should put in new gas and a fuel additive.

Blockage in the John Deere Zero Turn’s Fuel Filter

Between the gasoline lines is a fuel filter that traps debris before it can contaminate the fuel. Reduced fuel flow occurs when the filter becomes clogged from lack of regular maintenance.

Combustion in the engine could fail due to insufficient fuel. An yearly fuel filter replacement is recommended.

Replace the old gasoline filter with a brand new one if it gets blocked up. Install it so that the arrow on the filter points in the direction of fuel flow.

John Deere Zero Turn Mower Fuel Line Clogged

Old fuel can leave behind sticky deposits that might cause fuel lines to become blocked. This reduces fuel flow by closing up the fuel line’s orifice.

Once a blocked line is identified, the solution is to clear it. First, disconnect the line from your John Deere.

If the line is clogged, you can try spraying carburetor cleaner into it. Blow compressed air into the line after using the carb cleaner to dislodge the obstruction.

If you’re unable to remove the obstruction, you’ll need to replace the gasoline line.

A John Deere Zero Turn Mower with a Faulty Fuel Pump

Your zero-turn might not be starting because of a faulty fuel pump. The fuel pump is designed to pump fuel uphill to the carburetor.

A non-functioning fuel pump prevents fuel from reaching the carburetor, rendering the engine inoperable. It’s typical for carburetors to malfunction because of stale gas.

The fuel pump in most John Deere zero-turn mowers is a vacuum type. Using the same fuel for an extended period of time will deteriorate your fuel pump.

If your fuel pump is no longer able to pull fuel from the tank and deliver it to the carburetor via engine vacuum, it needs to be replaced.

The fuel pump should be replaced if fuel is spilling from it. When there are no obvious indicators of pump damage, you can still diagnose the problem by running a few tests.

  • You can turn off the fuel pump by turning the valve underneath the tank, or you can compress the fuel line with clamps.
  • Taking the hose away from the pump’s input will prevent any water from entering the pump. Keep the container below the gasoline tank so that gas can flow into it under gravity. Be sure the fuel pump is receiving fuel at this point.
  • Open the gasoline valve. Confirming fuel flow to the pump is as simple as observing fuel entering the storage tank. In any other case, you’ll need to look for a fuel limitation before you may go to the pump.
  • Turn off the gas. Remove the inlet hose and replace it.
  • If you want to check your fuel pump’s health, you’ll need to remove the hose from the carburetor and set it in a container.
  • Begin fueling the engine and turning it over. Keep an eye on the gasoline line to see if there is a continuous or pulsing flow of fuel.
  • Remove the fuel hose from the carburetor and restart the mower after the test is complete.

If the fuel flow from your John Deere is intermittent or otherwise inconsistent, you will need to replace the pump.

An Old John Deere Zero Turn Mower with a Filthy Carburetor

An unclean carburetor could be the cause of your John Deere zero-inability turn’s to start. The engine won’t turn over if the carburetor can’t control the flow of air and gasoline to it.

The failure of a carburetor is often attributable to stale fuel. This is due to the fact that stale fuel causes the fuel channels to get clogged, reducing the fuel flow. Sometimes, it leaves behind a varnish that makes moving parts stick and eventually stops working.

Cleaning the carburetor and replacing any worn or broken components is necessary if it is not functioning properly.

Here is a SOLUTION: I detailed how to clean a John Deere carburetor.

If you have a basic understanding of mechanics and experience handling small components, then you should be able to follow these instructions.

You can either take your mower to a small engine repair shop to have the carburetor cleaned or rebuilt, or you can buy a new carburetor assembly and install it yourself.

John Deere Zero Turn Mower with a Leaking Gas Cap

There needs to be a way for air to get into the gasoline tank through a vent. Because of the lack of a vent, fuel cannot escape the tank and reach the carburetor.

John Deere zero-turn mowers have a vent in the gasoline cap that lets the tank’s air pressure balance up with the surrounding atmosphere.

If your John Deere’s gas cap is faulty, you can test it by driving it with and without the cap. Remove the cap to let air into the fuel tank if your zero-turn won’t start when the cap is in place. A discharge of the vacuum could be audible.

Loosening the cap and trying to start the mower could indicate a gas cap venting issue.

Try running the mower with the gasoline cap securely fastened to see if you can replicate the problem of the engine cutting out and not starting again unless the cap is loosened.

An answer is to switch out the gasoline cap on a John Deere zero-turn mower.

John Deere Zero Turn Mower with a Faulty Spark Plug

Intermittent spark issues may prevent the engine from starting if the spark plugs are fouled, have broken porcelain, or have worn electrodes.

Make sure your spark plugs are in good working order by checking them. Assemble the spark plugs according to the manufacturer’s instructions, making that the wires are tight and the electrode gap is correct.

Solution: Take out the spark plug and check for carbon buildup or a broken porcelain insulator.

If one or more of the spark plugs are damaged, worn, or particularly dark in color, they should be replaced.

Spark plugs that are otherwise in good shape should have their tips dusted off with a tiny wire brush. Check the gap on the spark plugs and the connections of the wires.

John Deere Zero Turn Mower Air Filter Clogged

Your John Deere has an air filter installed to prevent debris from damaging the motor. Mower failure to start might occur if the filter is not frequently cleaned or replaced.

The air filter should be changed once a year and its condition should be monitored frequently throughout the mowing season. Clean the filter if you find it to be in good working order.

However, it is recommended to get a new one if the old one is severely torn or soiled.

The answer is simple: just check and clean the filter. If your John Deere won’t start because of a clogged air filter, try replacing it.

To clean a paper air filter in a John Deere:

  • Take out the filter and throw it away.
  • Make sure there isn’t any grit or dust that could get into the engine’s air filter. Use a dry cloth to remove any lingering debris from the filter housing and filter cap.
  • In order to release as much dirt as possible from the air filter, tap it against a hard surface.
  • Check if light is passing through the paper element by holding the filter up to a light.
  • If the filter allows you to see, keep using it. If there’s no light coming through, the filter is excessively dirty, or the filter is broken, you should get a new one.
  • Change the air filter.

John Deere Zero Turn Mower Wiring, Terminals, or Parts That Have Become Loose or Corroded

If the battery cables, wires, or other electrical components are damaged or come loose, continuity may be interrupted.

The ANSWER is to get rid of the rusting. Detach the battery and take out the rusty parts.

Using a small metal brush and either cola or a baking soda solution (2 cups of water mixed with 3 heaping tablespoons of baking soda), remove the corrosion.

Then, check that all of the components and wires are connected properly and installed tightly.

John Deere Zero Turn Tractor with Weak or Bad Battery

There will be no way to start the engine if the battery is dead or weak. If the battery isn’t holding a charge, charge it and try again; otherwise, get a new one.

A multimeter test should be performed on your zero-turn battery. Your battery has to be charged if the volt reading is lower than 12.7.

John Deere Zero Turn Mower With Faulty Safety Switch

There is an operator presence control system placed on your zero-turn to keep you secure. One possible reason your zero-turn won’t crank is a faulty safety switch.

You can solve this problem by using a multimeter to check each switch individually. Bypassing a safety switch is another option for locating a malfunctioning switch, although this should be done only during troubleshooting.

Never mow without first flipping the safety switch.

When a mower’s safety switch has been removed, it is dangerous to use the mower. Nobody can predict when they may require a safety switch, but having one available can prevent serious harm.

John Deere Zero Turn Mower Faulty Ignition Switch

If you turn the key but the car doesn’t start, the fault may lie with the ignition switch.

Whether you suspect the ignition switch is broken, you can test it with a multimeter to see if there is any continuity. Follow the instructions for your specific battery and starter solenoid to find the appropriate prongs.

Put the key in and turn it to the “on” position. In order to take a resistance reading, you must touch one probe to the B prong and the other probe to the S prong of the multimeter.

The resistance of a quality key switch for the ignition should be close to zero. If the resistance reading on your ignition key switch is infinity, you probably need to replace it.

Fix: replace out the ignition if it’s malfunctioning.

John Deere Zero Turn Tractor Starter Solenoid Fault

The electromagnetic “on/off” switch of a lawnmower solenoid activates the starter motor to get the engine cranking. If you hear a click or hum whenever you turn the key, it’s time to inspect the solenoid.

If a wire leading to your solenoid overheats and smokes or melts, there’s another red flag that something is wrong.

Answer: If your solenoid fails an inspection, you should get a new one.

John Deere Zero Turn Tractor Charging System Failure

John Deere zero-turn mowers sometimes have trouble starting due to a weak battery, which may be caused by issues with the charging system.

When the battery isn’t fully charged, the mower won’t start. This might happen if the charging system malfunctions.

Several different electrical components, most notably a faulty stator or alternator, could be at fault. You can use an ohm meter and this article to check the integrity of your charging system.

SOLUTION: If you’ve determined that your charging system is malfunctioning, take your mower to a John Deere zero-turn mower dealer near you for assistance.

The charging system is made up of numerous individual parts. If you don’t have any prior knowledge with lawn mower repair, you can just start replacing parts in the vain hope that one of them will solve the issue.

Electric lawn mower components might be pricey. Electric components are almost certainly final sale. You will be stuck with the costly component even if you discover later that it was not the cause of the issue.

John Deere Zero Turn Mower Wrong Choke Setting or Incorrect Operating Procedure

There are a few different ways to get your zero-turn started.

Be sure the Choke is not on

When trying to start a cold engine, you should tighten the choke. The lawn mower won’t start if the choke lever isn’t in the correct position.

  • A John Deere zero-turn mower from cold starts with:
  • Choke lever should be moved to full choke position.
  • Adjust the throttle so that it is in between the “off” and “rapid” positions.
  • To begin, insert the key into the ignition and turn it to the start position.
  • The choke should be turned off, so make sure the lever is in that position.
  • For the first few minutes of mowing, let the engine warm up at half throttle.

Verify that you are adhering to the procedures of the safety interlock system:

The purpose of the safety interlock mechanism is to protect you. If you do not meet the safety criteria for operating a John Deere, the mower will not start.

Before initiating a zero-turn, make sure the following safety conditions are met:

  • Come on in and take control.
  • To apply the brakes, turn the steering wheel all the way to the outside. Pull in the brake lever if available.
  • Turn off paid time off.

If you want to start your John Deere zero-turn, just do what was described above. You need to have the choke set properly and follow the safe starting instructions.