The smell of freshly cut grass, the gentle hum of the engine, and the feeling of a job well done – there’s nothing quite like a pristine lawn. But what happens when your trusty John Deere lawnmower refuses to cooperate? You may find yourself staring at it with a furrowed brow, wondering where to start. This guide will walk you through the common issues that prevent your old John Deere from firing up, providing a step-by-step solution for each. From troubleshooting fuel-related problems to checking the ignition system, we’ll equip you with the knowledge to bring your mower back to life.
So, why won’t your John Deere lawn mower start?
A stubborn John Deere mower can be the result of several issues. It could be a simple case of a clogged carburetor, a dead battery, or even a fouled spark plug. Fear not, with the right tools and a bit of patience, you can diagnose and fix these issues yourself.
The Pre-Start Checklist: Essential Steps
Before diving into complex repairs, it’s important to rule out the simple things that might be preventing your mower from starting. This checklist will help you troubleshoot basic issues and ensure you’re not missing an easy fix.
1. Fuel and Spark: The Heart of the Engine
Fuel Check:
- Fresh Fuel: Old gas can gum up the carburetor and prevent your engine from running smoothly. Always use fresh gasoline and ensure it’s the correct octane rating recommended by John Deere.
- Fuel Lines: Inspect your fuel lines for cracks, leaks, or kinks. A damaged fuel line can restrict fuel flow and stop your mower from starting.
- Fuel Filter: A dirty fuel filter can clog the fuel flow, leading to starting problems. Replace the fuel filter if it’s dirty or has been in use for an extended period.
Spark Check:
- Spark Plug: The spark plug plays a crucial role in igniting the fuel-air mixture. If it’s worn out or fouled, it won’t generate the spark needed for combustion.
- Visual Inspection: Remove the spark plug and check its condition. A healthy spark plug will have a clean, light-tan electrode.
- Spark Test: Connect a spark plug tester to the spark plug wire and ground it to the engine block. Crank the engine and look for a bright blue spark. If the spark is weak or absent, replace the spark plug.
- Spark Plug Wire: A cracked or worn spark plug wire can prevent a spark from reaching the plug. Inspect the wire for damage and replace it if necessary.
2. The Battery: Powering Up Your Mower
- Battery Check: If your mower uses a battery, ensure it’s charged.
- Voltage Test: Use a multimeter to check the battery voltage. A fully charged battery should read around 12.6 volts.
- Battery Connection: Make sure the battery terminals are clean and securely connected. Corrosion can prevent proper current flow.
- Starter Switch: Ensure the starter switch is in the “on” position and that the electrical connections are secure.
- Start Button: Check that the start button is clean and working. A dirty button can prevent it from making proper contact.
Troubleshooting Common Issues
If the pre-start checklist hasn’t yielded results, you may need to delve deeper into potential problems:
1. Carburetor Troubles: Fuel Delivery Problems
The carburetor is responsible for mixing fuel and air before sending it to the engine. If the carburetor is dirty or malfunctioning, your mower won’t start.
- Carburetor Cleaning: If the carburetor is clogged, you can clean it with carburetor cleaner and a small brush.
- Disassembly: Disconnect the fuel line and remove the carburetor from the engine.
- Cleaning: Soak the carburetor parts in carburetor cleaner and use a small brush to remove any dirt or debris.
- Reassembly: Rinse the parts with clean water and let them air dry. Reassemble the carburetor and reinstall it on the engine.
- Carburetor Adjustment: If the carburetor is not adjusted correctly, it may not be delivering the proper fuel-air mixture. Adjust the idle and air screws according to the manufacturer’s instructions.
- Carburetor Replacement: In some cases, the carburetor may be too worn out to be repaired. If this is the case, you will need to replace it with a new one.
2. The Air Filter: Breathing Room for Your Engine
A clogged air filter can restrict airflow to the engine, causing starting problems.
- Air Filter Inspection: Remove the air filter and inspect it for dirt or debris.
- Air Filter Cleaning or Replacement: If the air filter is dirty, clean it with soap and water or replace it with a new one.
3. The Ignition System: Sparking Life into Your Engine
The ignition system is responsible for creating the spark that ignites the fuel-air mixture. If the ignition system is faulty, your mower won’t start.
- Ignition Coil: The ignition coil transforms low-voltage battery current into high-voltage current that powers the spark plug. A faulty ignition coil can prevent the spark plug from firing.
- Visual Inspection: Check the ignition coil for signs of damage or corrosion.
- Resistance Test: Use a multimeter to test the resistance of the ignition coil.
- Replacement: If the ignition coil fails, replace it with a new one.
- Ignition Switch: The ignition switch controls the flow of current to the ignition system. A faulty ignition switch can prevent the spark plug from receiving power.
- Visual Inspection: Check the ignition switch for signs of damage or corrosion.
- Continuity Test: Use a multimeter to check the continuity of the ignition switch.
- Replacement: If the ignition switch is faulty, replace it with a new one.
Beyond the Basics: Advanced Troubleshooting
If you’ve checked the basics and still can’t get your John Deere mower started, you may need to delve into more advanced troubleshooting.
- Compression Test: A compression test measures the pressure in the cylinders when the engine is cranked. Low compression can indicate a problem with the piston rings, valves, or cylinder head.
- Fuel Pump: A faulty fuel pump can prevent fuel from reaching the carburetor. Check the fuel pump for leaks or damage and replace it if necessary.
- Electrical System: If you suspect an electrical problem, you can use a multimeter to test the voltage and current in different parts of the electrical system.
Important Note: When working on your John Deere lawn mower, always disconnect the spark plug wire to prevent accidental starting. Be cautious when working with gasoline and use proper safety gear.
Seek Professional Help: When to Call in the Experts
If you’ve exhausted all troubleshooting options and your mower still refuses to start, it’s time to call in the experts. A qualified mechanic can diagnose the problem and perform the necessary repairs.
Here are some signs that it’s time to seek professional help:
- Complex Engine Problems: If the engine is making unusual noises or exhibiting other signs of serious damage, it’s best to leave the repairs to a professional.
- Safety Concerns: If you’re uncomfortable working on the mower or are unsure about the repairs, it’s always better to err on the side of caution and call a mechanic.
Maintaining Your John Deere Lawn Mower:
To prevent future starting problems and keep your John Deere mower running smoothly, it’s important to perform regular maintenance.
- Regular Oil Changes: Change the engine oil every 25 hours of operation or as recommended in your owner’s manual.
- Air Filter Cleaning: Clean or replace the air filter regularly.
- Spark Plug Replacement: Replace the spark plug every 100 hours of operation or as recommended in your owner’s manual.
- Carburetor Cleaning: Clean the carburetor every season or if you notice starting problems.
Conclusion:
While starting an old John Deere lawn mower can seem daunting, the process is manageable with a little patience and knowledge. By following the steps outlined in this guide, you can diagnose and fix common starting issues. Remember to prioritize safety, use proper tools, and don’t hesitate to call in a professional if needed. With a little effort, you can have your John Deere running like new and enjoying the fruits of a well-maintained lawn.
Frequently Asked Questions
1. What are some common problems with starting an old John Deere lawnmower?
Older John Deere lawnmowers can experience a variety of issues preventing them from starting. Common problems include a dead battery, clogged fuel lines, spark plug issues, worn-out starter components, or a faulty ignition system.
Identifying the specific issue requires a systematic approach, starting with basic checks like the battery and moving on to more complex components.
2. How do I check the battery on my old John Deere lawnmower?
To check the battery, first, make sure the battery terminals are clean and free of corrosion. Then, use a voltmeter to measure the battery’s voltage. A fully charged battery should read around 12.6 volts. If the voltage is significantly lower, the battery may need replacement.
If the battery appears to be charged but the mower still won’t start, there may be an issue with the battery connections or the starting system.
3. How do I clean the fuel lines on my old John Deere lawnmower?
Fuel lines can become clogged with debris or varnish over time, preventing fuel from reaching the carburetor. To clean them, disconnect the fuel lines from the tank and carburetor. Then, use a small brush or a piece of wire to clean the inside of the lines.
You can also flush the lines with fuel line cleaner or a mixture of gasoline and carburetor cleaner. After cleaning, reconnect the fuel lines and make sure they are securely fastened.
4. How do I check the spark plug on my old John Deere lawnmower?
The spark plug is a crucial component for igniting the fuel-air mixture in the engine. To check it, remove the spark plug from the cylinder head and inspect it for signs of wear, fouling, or damage.
A properly functioning spark plug should have a clean, gapless electrode and should produce a strong blue spark when tested with a spark plug tester. If the spark plug is damaged or fouled, it needs to be replaced.
5. How do I troubleshoot a faulty ignition system on my old John Deere lawnmower?
A faulty ignition system can prevent the spark plug from firing, making it impossible to start the engine. To troubleshoot the ignition system, first, check the spark plug wires for damage or loose connections.
Then, check the ignition coil for continuity using a multimeter. If the coil is faulty, it needs to be replaced.
6. What maintenance tips should I follow to keep my old John Deere lawnmower running smoothly?
Regular maintenance is essential for keeping an old lawnmower running smoothly. This includes changing the oil and filter, cleaning the air filter, inspecting the spark plug, and checking the fuel lines.
Also, make sure to store the lawnmower properly during the off-season to prevent corrosion and damage.
7. What are some common resources for finding parts and repair information for old John Deere lawnmowers?
There are several resources available for finding parts and repair information for old John Deere lawnmowers. You can check with local John Deere dealers, online retailers specializing in lawnmower parts, or visit online forums and communities dedicated to classic lawnmower restoration.
Additionally, John Deere offers a wealth of resources on its website, including owner’s manuals, parts diagrams, and troubleshooting guides.