Lawn Mower Will Not Start
- Fuel is old or contaminated: Drain stale fuel and refill with fresh gasoline recommended for your engine. Use fuel stabilizer when storing the mower for long periods.
- Fuel valve or choke setting incorrect: Confirm the fuel valve is open where equipped, then follow the correct choke and throttle starting procedure.
- Spark plug problem: Inspect the spark plug for fouling, damage, loose wiring, or incorrect gap. Replace the plug if worn.
- Safety switch not engaged: On riding mowers, sit in the seat, set the parking brake, disengage the blades, and place the transmission in the correct position before starting.
- Battery weak: Check battery voltage, terminals, cable corrosion, fuse condition, and charging system on electric-start models.
Engine Starts but Runs Rough or Stalls
- Dirty air filter: Clean or replace the engine air filter according to the engine manual.
- Old fuel: Replace old fuel and inspect the fuel line and fuel filter for blockage or deterioration.
- Carburetor issue: A dirty carburetor jet or incorrect adjustment can cause surging, stalling, or poor idle performance.
- Choke left on: Move the choke to the run position after the engine starts and warms up.
- Grass buildup: Remove grass clippings and debris from cooling fins, mower deck, and engine ventilation areas after the engine cools.
Mower Does Not Cut Grass Properly
- Blade is dull: Sharpen or replace the mower blade if grass tips appear torn, ragged, or brown after mowing.
- Blade installed incorrectly: Confirm the cutting edge faces the correct direction and the blade is securely installed.
- Deck height too low: Raise the cutting deck when mowing tall, wet, or uneven grass.
- Grass is too wet: Wait for grass to dry before mowing to reduce clumping and uneven cutting.
- Deck clogged: Shut off the engine, remove the spark plug wire where applicable, and clean packed grass from the underside of the deck.
Self-Propelled Mower Will Not Move
- Drive control not engaged: Squeeze the self-propel handle fully and check that the cable moves correctly.
- Drive cable out of adjustment: Adjust the traction cable according to the model-specific manual if the wheels do not engage properly.
- Drive belt worn or broken: Inspect the self-propel belt for cracks, glazing, fraying, or breakage.
- Drive wheels worn: Check wheel gears, drive pawls, and wheel tread for wear or damage.
- Debris around drive system: Remove grass, mud, stones, or string tangled around wheels, pulleys, and drive components.
Riding Mower Will Not Move
- Parking brake engaged: Release the parking brake before attempting to drive.
- Transmission bypass engaged: Check whether the freewheel or bypass lever is in the disengaged position.
- Drive belt damaged: Inspect the transmission drive belt and pulley system for wear, slipping, or broken components.
- Transmission fluid or hydrostatic issue: Follow the model-specific maintenance instructions for hydrostatic transmission service.
- Brake linkage problem: Inspect the brake pedal, linkage, springs, and return mechanism for damage or binding.
Blades Will Not Engage
- PTO switch not activated: Pull or engage the PTO control fully according to the operating instructions.
- Deck belt worn or broken: Inspect the mower deck belt for cracks, fraying, stretching, or breakage.
- Safety switch issue: Make sure the operator is seated and all required safety conditions are met.
- PTO clutch problem: Electric PTO clutches may require diagnosis if the switch is on but blades do not engage.
- Deck pulley seized: Inspect spindle pulleys and idler pulleys for noise, wobble, overheating, or restricted movement.
Battery, Charging & Electrical Problems
- Battery will not charge: Check battery terminals for corrosion, inspect wiring, and confirm the charging system is operating.
- Starter clicks but engine will not crank: Charge the battery and inspect battery cables, starter solenoid, fuse, and ground connection.
- Headlights not working: Check bulbs, wiring connections, fuse condition, and the ignition switch position.
- Blown fuse: Replace only with the correct fuse rating. Repeated blown fuses may indicate a short circuit or damaged wiring.
Routine Maintenance Tips
- Check engine oil: Inspect the engine oil level before each use and change oil at the interval listed in the engine manual.
- Clean the mower deck: Remove grass buildup from under the deck after mowing, especially when cutting wet grass.
- Inspect belts regularly: Check deck belts and drive belts for cracking, glazing, fraying, or poor tension.
- Sharpen blades safely: Disconnect the spark plug wire or battery before removing blades. Balance blades after sharpening.
- Prepare for storage: Clean the mower, stabilize or drain fuel, charge the battery, and store the machine in a dry location.
Safety note: Always stop the engine, remove the ignition key, disconnect the spark plug wire or battery, and wait for all moving parts to stop before cleaning the deck, replacing blades, adjusting belts, or performing maintenance.