One of the most common issues with John Deere mowers is that the engine turns over but won’t start. A lawn mower not starting could be caused by a number of things. An engine relies on three key components; air intake, spark, and gas. If one of these is not working as it should then the riding mower won’t start.
When the engine turns over it means the battery has sent the necessary electrical impulses to the spark plugs and therefore issues with the battery can be ruled out. With that in mind, if the John Deere Zero Turn turns over but won’t start, then it is not an issue with the battery and is more likely to be an issue with something else such as the carburetor.
The John Deere 100 Series seem to be the models most affected by this issue including the John Deere 1025r, John Deere e100, John Deere I100 and the John Deere d110.
Related: John Deere 1025R Problems
When a John Deere tractor turns over but won’t start, there are a number of issues that could be causing it. The most common issues include a dirty carburetor and a faulty spark plug. Clean the carburetor and remove then reattach the spark plug before trying to start the engine.
Troubleshoot JD Lawn Tractor That Turns But Won’t Start
There are a number of possible reasons a John Deere diesel tractor cranks but won’t start. Below we work through them all so you can get your tractor up and running again as quickly as possible.
Replace Old Gasoline
- Firstly, check the gasoline. If the gasoline is old then it can cause issues with starting the lawn mower. Due to this, gasoline that has been sitting in the mower for a season or more may be the cause of the problem.
- Completely empty the gas tank.
- Safely dispose of the old gasoline.
- Refill the tank with fresh gas.
- Turn the engine on.
Check Oil Level
- Measure the oil level.
- In addition, check the color and consistency of the oil.
- Refill if needed and the existing oil is in good condition.
- Most importantly, empty the oil if it is black or has been used for 25-50 hours. Fill with new oil.
Set the Throttle to the Full Revs Position
- If the choke is manual on your lawn mower, turn it on. Some mowers have an automatic choke that you don’t need to adjust so check the manual for the tractor model being used.
- Start the engine after turning the choke on.
- Turn the choke off after a couple of minutes of the engine running.
Use the Primer Button
- Firstly, press the primer button to send fuel to the carburetor.
- Then, turn the engine on. As a result of the additional fuel, the engine should start on the first attempt.
Check the Air Filter
- Firstly, locate the air filter.
- Secondly, check the condition of the filter. If the air filter is clogged it will affect the mower.
- Finally, clean or replace the air filter.
Connect the Spark Plug
- Remove the spark plug if it is connected.
- Check the condition of the plug.
- Reconnect it or connect a new spark plug.
- If needed, tighten the screw holding the spark plug in place to ensure a strong connection.
Pull Out the Starter Rope
- Pull the starter rope and let it return to its original position.
- Do this up to 4 times until the engine starts.
- If needed, use the primer button to help the engine start.
- The engine should start. If it does not, it could be because the fuel needs to evaporate.
Clean Dirty Carburetor
- Turn the mower off and locate the carburetor.
- Remove the air filter housing.
- Check the condition of the carburetor.
- Spray with cleaner and make sure there is nothing clogged inside the carburetor.
- Turn on the engine.
- If the engine starts but then stops, take the carburetor apart and clean it.
For John Deere Diesel Tractor Owners
If your diesel tractor is cranking but not starting, use the tips below to help fix the issue.
Most Common Problem: Fuel Filter
The first thing to do when fuel system troubleshooting is to look at the fuel filter. Signs of a bad fuel filter include clogged ducts and dirty fuel lines.
Remove the filter and look for signs of damage or a build up of dirt. The filter can be cleaned if there is dirt or clogs. If the filter is damaged then it needs to be replaced. The steps on how to remove and replace the filter are outlined below.
Role of Fuel Filter in Diesel Engine JD Tractors
The fuel filter is an integral part of the JD tractor diesel engine. It is responsible for removing abrasive particles and dirt from the fuel. This prevents clogging of the fuel injectors and helps to protect the engine from damage.
If the engine lacks power this can be because the fuel filter is clogged which reduces or stops the flow of fuel going to the injectors.
Remove and Replace Fuel Filter
The fuel filter is a common cause of John Deere tractor starting problems. Fortunately, it is a part that can be easily replaced yourself.
To replace the fuel filter you will need:
- Drain pan
- Shock towels
- New fuel filter (Check the operator’s manual to ensure you have the right fuel filter for your engine)
- Safety glasses
Step 1. Park the Mower on a Level Surface
Firstly, park the mower on a hard, flat surface. Secondly, put the parking brake on, shut the engine off and remove the keys.
Step 2. Locate the Fuel Filter
Before starting, wait for the engine to cool. Once cooled, raise the seat to locate the fuel filter on the John Deere riding lawn mower.
Step 3. Inspect the Condition of the Filter and Hoses
Once you can see the fuel filter, close the fuel shutoff valve. Then, inspect the fuel filter and hoses. Look closely for signs of wear and tear.
Step 4. Check the Compatibility of the New Filter
If a new filter needs to be installed, make sure it works in the same way as the old filter. Look closely at the small arrow on both filters, this indicates the direction of the fuel flow. Both of the filters need to have the same fuel flow direction.
Step 5. Loosen Old Fuel Filter
Place the drain pan under the fuel filter then use the pliers to loosen the filter and the hose clamps. Move the hose clamps away from the filter.
Step 6. Remove Old Fuel Filter
Twist and pull the hoses from the old filter. Remove the old filter and raise the fuel lines vertically to avoid fuel drainage.
Step 7. Attach the New Fuel Filter
Attach the hoses to the new filter (remember to make sure the arrow points in the correct direction). Then reposition the hose clamps to secure the filter.
Step 8. Dispose of the Old Oil Filter and Fuel
After that, clean up any spilled fuel and properly dispose of the old filter and fuel.
Step 9. Run the Engine
Finally, start the engine and run it briefly. Meanwhile, check for leaks.
Check out this video for tips on changing the fuel filter on a John Deere compact utility tractor.
Maintenance Tips to Avoid JD Lawn Mower Starting Problems
Simple maintenance is key to keeping JD lawn mowers in top condition. When you stay on top of the maintenance the repairs will be few and far between. These simple tips will go a long way:
- Keep the fuel tank topped up.
- Replace old gas with fresh gas. (This is particularly important at the start of a new season/year.)
- Clean the air filter before turning the engine on.
- Ensure the spark plug is firmly in place. If necessary, screw the plug into position or replace it with a new one.
- Turn on the choke (if it is manual) and remember to turn it off after a few minutes of the engine running.
- Use the primer. (Don’t press it more than 4 times each use.)
Still have questions? We’ve got the answers below.
Can you move a zero turn mower that won’t start?
Yes, you can manually push the mower but first you need to push the hydraulic pins in to release the hydraulic gears, then you need to put the handlebars in, put it into the run position (but don’t turn it on) and release the parking brake to be able to push the mower.
How many safety switches does a John Deere riding mower have?
John Deere riding lawn mowers have three safety switches. One protects the brakes, one manages the blades or accessories, and the third is to protect against operation without an operator.
How much does it cost to replace a fuel pump?
On average, a fuel pump costs between $25 – $250 depending on the vehicle.
John Deere lawn mowers have an excellent reputation but occasionally small issues can cause big setbacks. These mowers experience issues with the engine turning over but not starting. This can be solved quickly with simple tractor engine troubleshooting and by ensuring all parts are clean and in good condition. Keeping the mower well maintained is essential to its longevity.