How to Start a John Deere Lawn Mower: Direct Answer
To start a John Deere lawn mower, ensure the parking brake is engaged and the mower deck is disengaged first. For riding mowers, sit in the seat to activate the safety switch; for push mowers, hold the safety bail firmly. Set the throttle to the choke or fast position if the engine is cold. Insert the ignition key and turn it to the start position until the engine fires up, then adjust the throttle to the desired running speed. Always perform pre-start safety and inspection checks before attempting to start any John Deere mower.
Understanding Your John Deere Mower’s Starting System
John Deere manufactures both riding mowers and push mowers, each with slightly different starting mechanisms. Most modern John Deere residential mowers feature either electric start (with an ignition key) or recoil start (pull cord) systems. Understanding which system your specific model uses is essential before attempting to start the engine.
John Deere riding mowers typically fall into several series: the D100 series (entry-level), E100 series (mid-range), S100 series (budget-friendly), and the more advanced X300 series (premium residential). Push mowers generally include the Mower 100 series and various self-propelled models. Each series may have subtle variations in control placement and starting procedures.
Pre-Start Safety and Inspection Checks
Essential Safety Switches on John Deere Riding Mowers
Before starting any John Deere riding mower, you must understand the safety interlock system. These safety switches are designed to prevent accidental startup and are mandatory for safe operation.
- Seat Switch: On riding mowers, you must be seated in the operator’s seat to complete the safety circuit. This prevents the mower from starting if no one is in the seat.
- Brake Pedal Switch: The parking brake must be fully engaged before starting on most models.
- Reverse Operation Safety System (ROS): On mowers equipped with ROS, this switch allows operation in reverse while keeping the operator alert.
- Mower Deck Clutch: Ensure the PTO (Power Take-Off) is disengaged before starting the engine.
Checking Oil and Fuel Levels
Proper fluid levels are critical for engine health and reliable starting. Always check oil and fuel levels before each mowing session.
To check oil level: Park your John Deere mower on a level surface. Locate the oil dipstick (usually near the engine front on riding mowers, or on the engine block on push mowers). Pull the dipstick out, wipe it clean, reinsert it fully, then pull it out again to read the oil level. The oil should be between the full and add marks on the dipstick. John Deere recommends using high-quality SAE 30 oil for most operating conditions, though you should consult your owner’s manual for specific viscosity requirements based on your engine manufacturer (Briggs & Stratton, Kawasaki, or Kohler).
To check fuel level: Inspect the fuel tank sight gauge or remove the fuel cap to verify adequate fuel supply. Always use fresh gasoline—fuel older than 30 days can deteriorate and cause starting problems. John Deere recommends using unleaded gasoline with an octane rating of 87 or higher. If your fuel has been sitting for an extended period, consider draining and replacing it to avoid carburetor issues.
Visual Inspection Checklist
Before attempting to start your John Deere mower, perform these essential visual checks:
- Inspect the air filter for dirt buildup and clean or replace as needed
- Check for loose or damaged wiring connections
- Ensure the mower deck is free of debris and buildup
- Verify all control cables are properly connected and functioning
- Inspect the battery terminals for corrosion and secure connections on electric-start models
Starting Procedure for John Deere Riding Mowers
Electric Start Riding Mowers (D100, E100, S100 Series)
The following steps apply to most John Deere electric-start riding mowers with an ignition key system:
- Set the parking brake: Press the brake pedal down and engage the parking brake lever or button. This activates the brake safety switch, allowing the starting circuit to complete.
- Disengage the mower deck: Move the PTO switch to the off position to disengage the mower deck. Starting with the deck engaged can strain the engine and damage the belt system.
- Settle into the operator’s seat: Sit fully in the seat to activate the seat safety switch. Most John Deere riding mowers will not start unless an operator is seated.
- Set the throttle: Move the throttle lever to the choke or fast position. For cold starts, choke position provides the rich fuel-air mixture needed for starting. For warm starts, you can begin in the fast position.
- Insert the ignition key: Insert the key into the ignition switch if not already in place.
- Turn the key to start: Rotate the key to the START position and hold it there until the engine fires. Do not hold the key in start position for more than 15 seconds continuously to prevent starter motor damage.
- Release the key: Once the engine starts, release the key and allow it to return to the ON/RUN position.
- Warm up the engine: Let the engine idle for 2-3 minutes before engaging the mower deck or driving. This allows oil to circulate and the engine to reach operating temperature.
Using the Choke Control Properly
The choke control enriches the fuel-air mixture for easier cold starts. On most John Deere riding mowers, the choke is integrated into the throttle lever. Pull the throttle lever fully forward (toward the rabbit symbol with a choke indicator) to engage the choke. After the engine starts and runs roughly for 10-15 seconds, gradually push the throttle back to the fast position. For optimal performance and fuel economy, avoid prolonged choke operation once the engine is warm.
Starting Procedure for John Deere Push Mowers
Recoil Start Push Mowers
John Deere push mowers typically use a recoil starter system with a pull cord. The following procedure ensures safe and effective starting:
- Prepare the work area: Ensure the mower is on flat, stable ground away from obstacles and bystanders.
- Check fuel and oil: Verify adequate fuel and correct oil level as described earlier.
- Prime the engine: Locate the primer bulb (usually a small rubber bulb near the carburetor). Press it firmly 2-3 times to deliver fuel directly to the carburetor. This is especially important for cold starts and engines that have been sitting.
- Set the throttle: Move the throttle lever to the fast/choke position for cold starts.
- Engage the safety bail: On walk-behind mowers, the safety bail (a bar near the handle) must be held against the handle to complete the safety circuit. Squeeze the bail toward the handle grip.
- Pull the starter cord: Firmly pull the recoil starter cord outward with a quick, confident motion. Allow the cord to rewind fully before pulling again if the engine doesn’t start on the first attempt.
- Warm up: Once the engine starts, let it run at idle for 1-2 minutes before engaging the blade or pushing the mower.
Self-Propelled Mower Starting
Self-propelled push mowers follow the same procedure, but you may need to release a drive clutch lever or pull a separate drive bar to engage the self-propulsion feature. Always consult your specific model’s owner’s manual for drive system operation.
Troubleshooting Common Starting Issues
Engine Cranks But Won’t Start
If your John Deere mower’s engine cranks over but fails to start, consider these common causes:
- Stale fuel: Gasoline older than 30 days can deteriorate and fail to ignite. Drain the fuel tank and carburetor, then refill with fresh gasoline.
- Flooded carburetor: Excess fuel in the carburetor can flood the engine. Remove the spark plug, pull the starter cord several times to clear excess fuel, and reinstall the spark plug.
- Faulty spark plug: Inspect the spark plug for carbon buildup, damage, or improper gap. Replace if necessary with the manufacturer-recommended plug type.
- Clogged fuel filter: A clogged fuel filter restricts fuel flow to the carburetor. Replace the filter if it’s been in service for an extended period.
- Dirty air filter: A severely clogged air filter restricts air intake, preventing proper combustion. Clean or replace the air filter element.
Starter Motor Problems on Riding Mowers
Electric-start riding mowers may experience these starter-related issues:
- Weak battery: A discharged or failing battery cannot provide sufficient cranking power. Test battery voltage with a multimeter—healthy 12-volt batteries should read 12.6 volts or higher when fully charged.
- Corroded battery terminals: Clean battery terminals with a wire brush and apply a terminal protectant spray to prevent future corrosion.
- Faulty safety switches: Malfunctioning seat, brake, or PTO switches can prevent the starting circuit from completing. Test each switch with a multimeter for continuity.
- Starter solenoid issues: The solenoid may click but fail to engage the starter motor. This component typically cannot be serviced and must be replaced.
Winter Storage and First-Spring Startup
Many starting problems occur after seasonal storage. To prevent issues when starting your John Deere mower in spring:
- Drain old fuel at the end of the mowing season or add a fuel stabilizer like STA-BIL
- Change the oil and filter before storage
- Remove and inspect (or replace) the spark plug
- Clean or replace the air filter
- Disconnect the battery or use a battery maintainer/trickle charger during storage
- Check tire pressure and lubricate moving parts
Battery Maintenance for Electric-Start Models
Proper battery maintenance ensures reliable starts throughout the mowing season. John Deere electric-start riding mowers typically use 12-volt batteries ranging from 280 to 350 cold-cranking amps.
Key battery maintenance practices include:
- Keep battery terminals clean and free of corrosion
- Check battery fluid level monthly in non-sealed batteries and top off with distilled water if needed
- Use a battery charger or maintainer during extended storage periods
- Inspect battery cables for fraying, cracks, or loose connections
- Replace batteries older than 3-4 years or those showing signs of swelling or case damage
Frequently Asked Questions
Why won’t my John Deere mower start after sitting for a long time?
Extended storage periods often cause fuel deterioration, which leads to hard starting or no-start conditions. Stale fuel leaves gummy deposits in the carburetor that obstruct fuel flow. Additionally, the battery may discharge if not maintained. Try draining old fuel, replacing it with fresh gasoline, checking the spark plug, and ensuring the battery is fully charged. Consider adding a fuel system cleaner to the fresh fuel to help dissolve existing deposits.
How do I know if my John Deere carburetor is flooded?
Signs of a flooded carburetor include a strong gasoline smell, black or wet spark plug after attempted starts, engine sputters or backfires, and visible fuel leakage from the carburetor. To resolve flooding, remove the spark plug and pull the recoil cord several times with the plug removed to allow excess fuel to escape. Allow the cylinder to dry for 10-15 minutes before reinstalling the spark plug and attempting another start.
What should I do if the safety seat switch is preventing my riding mower from starting?
If your riding mower won’t start even with someone seated, the seat safety switch may be faulty. First, verify the seat switch connector is properly plugged in under the seat. You can test the switch with a multimeter for continuity. A faulty seat switch should be replaced promptly—do not bypass safety switches, as they prevent serious injury from runaway mowers. Consult your authorized John Deere dealer or qualified small engine technician for replacement.
Can I use any type of gasoline in my John Deere lawn mower?
John Deere recommends using fresh unleaded gasoline with an octane rating of 87 or higher (R+M/2 method). Avoid gasoline containing more than 10% ethanol, as higher ethanol blends can cause fuel system damage and starting problems. Fuel with ethanol content can also absorb water from the atmosphere over time, leading to phase separation. If ethanol-blended fuel is your only option, add a fuel stabilizer and use the fuel within 30 days to minimize potential issues.
