When your Briggs and Stratton lawn mower refuses to turn on or won’t even crank, it can turn mowing from a simple chore into a major headache. Whether you own a walk-behind, self-propelled, or riding mower with a Briggs & Stratton engine, this guide will help you find—and fix—every common cause for a no-start condition. Most problems are simple to diagnose and resolve at home, saving you time, money, and frustration.
Quick-Check: Common Reasons Your Briggs & Stratton Mower Won’t Turn On
- Empty fuel tank or stale/old gasoline
- Battery dead or not connected (for electric start and riding mowers)
- Disconnected or loose spark plug wire
- Dirty, fouled, or damaged spark plug
- Clogged air filter or fuel filter
- Carburetor gummed up from old fuel
- Blade control lever or safety bail not engaged (walk-behind models)
- Choke not set for cold start (gas models)
- Primer bulb not functioning (if equipped)
- Faulty or disengaged safety switches (seat, brake, blade PTO for riding mowers)
- Blown fuse (riding and electric start models)
- Starter solenoid, starter motor, or ignition switch failure
- Mechanical jam in blade or engine (seized or stuck)
1. Fuel and Gasoline Checks
- Fresh Gas: Gasoline degrades in 30 days or less. Always start the season with new, clean fuel. Drain and replace old or stale gas in both tank and carburetor.
- Fuel Tank: Ensure tank is full. If the mower sat unused, water or debris could block the fuel outlet—inspect and clean if needed.
- Fuel Filter and Lines: Check for blockages, kinks, or collapsed lines. Replace clogged fuel filters and damaged lines promptly.
- Choke and Primer: For cold starts, set the choke ON and press the primer bulb 2–3 times (if equipped). Replace cracked bulbs or cables if not working.
2. Battery and Electrical System (Electric Start & Riding Mowers)
- Battery Charge: Ensure the battery is fully charged. Use a charger if needed, or jump from a car battery (12V only, for riding mowers).
- Battery Cables: Check for corrosion, loose terminals, or disconnected cables. Clean and reattach as needed.
- Blown Fuses: Most electric start and riding models have a main fuse. Replace any blown fuses found near the battery or starter solenoid.
- Ignition Switch: Turn the key and listen for a click or the starter motor. No sound? Suspect switch, wiring, or solenoid faults.
- Starter Motor/Solenoid: If the starter “clicks” but doesn’t spin, tap the solenoid lightly or check wiring. Replace if faulty.
3. Spark Plug and Ignition Checks
- Spark Plug Wire: Ensure the plug wire is snapped securely onto the spark plug.
- Spark Plug Condition: Remove and inspect the plug for black soot, rust, oil, or damage. Clean or replace as needed. Set the correct gap (usually 0.028–0.030 inches).
- Ignition Coil: If you see no spark at the plug (test by grounding against the engine and pulling cord/turning over), the ignition coil may be faulty and needs replacing.
4. Air and Fuel Filter Checks
- Air Filter: Remove and check for dirt or debris. Clean foam filters with soapy water, dry, and oil lightly. Replace paper filters if clogged or torn.
- Fuel Filter: Replace annually or when dirty to ensure fuel reaches the carburetor.
5. Carburetor and Fuel Delivery Issues
- Gummed Carburetor: Old fuel can clog jets and float valves, preventing start. Spray carburetor cleaner into the intake and try to start. If it fires briefly, remove and clean or rebuild the carburetor.
- Fuel Flow: Disconnect fuel line at carburetor; fuel should flow freely into a container. If not, check tank, lines, and filter for blockages.
- Carburetor Gasket Leaks: Replace any torn or missing gaskets to prevent air leaks and hard starting.
6. Safety Switches and Controls
- Walk-Behind: Squeeze the blade control bar fully against the handle while starting. Some mowers require holding a start button at the same time.
- Riding: Sit on the seat, press brake/clutch pedal fully, and ensure blade PTO lever is OFF. All safety switches must be engaged to start.
- Wiggle levers or pedals to “wake up” sticky switches after long storage.
- Replace broken or faulty switches promptly for safety and reliability.
7. Blade and Mechanical Obstructions
- Disconnect spark plug or battery before inspecting under the deck!
- Check for debris, sticks, or clumps of grass jamming the blade or engine. Remove all blockages before attempting to start.
- The blade should spin freely by hand (wear gloves). If stuck, resolve mechanical jams before further troubleshooting.
- On rare occasions, seized engine or internal damage can prevent turning over—consult a repair shop if you suspect internal engine issues.
8. Additional Steps for First-Time or Seasonal Starts
- Replace old gas and perform a tune-up (new spark plug, oil, filters) after winter storage.
- Check for rodent damage (chewed wires, nests) if mower was stored in a shed or garage.
- Prime the carburetor or set choke for first start of the season, following the manual.
Preventive Maintenance for Reliable Starts
- Use only fresh gasoline; add stabilizer for winter storage
- Replace air filter, spark plug, and fuel filter every season
- Clean or rebuild carburetor annually if used heavily
- Charge and store batteries indoors (for electric start)
- Keep deck, blade, and engine area clean of grass and debris
- Inspect all controls and switches for wear or damage
- Store mower in a dry, sheltered location
Frequently Asked Questions (FAQ)
Why does my Briggs and Stratton mower do nothing when I turn the key?
For riding or electric start models, check the battery charge, fuses, safety switches (seat, brake, blade), and ignition switch wiring.
Why won’t my Briggs and Stratton mower even try to turn over?
Usually caused by a dead battery, blown fuse, faulty ignition switch, or disengaged safety switch. For pull-start models, also check blade and engine for jams.
How can I tell if the spark plug is the problem?
Remove and inspect it. If fouled, black, or wet, replace with a new, correctly gapped plug. Ensure the wire snaps on securely.
What if my mower clicks but doesn’t crank?
Likely a weak battery, stuck solenoid, or faulty starter motor. Tap solenoid, recharge battery, and check wiring connections.
When should I call a repair shop?
If you’ve checked fuel, spark, switches, battery, and for jams, but the mower still won’t turn on—especially if the engine is seized or you hear unusual noises—seek professional help.
Conclusion: Get Your Briggs and Stratton Mower Running Again
Most starting problems with Briggs & Stratton mowers are simple: fuel, spark, battery, safety switches, or a jam. Use this guide to quickly diagnose and fix the issue—and you’ll enjoy reliable mowing for years to come!
Ready for smooth starts and easy mowing? Follow these steps and keep your yard looking great every season!