Lawn Mower Will Not Start
- Fuel is old or contaminated: Drain stale fuel and refill with fresh gasoline recommended for your mower engine.
- Fuel valve or choke setting incorrect: Make sure the fuel valve is open where equipped and follow the correct choke, primer, or throttle starting procedure.
- Spark plug problem: Inspect the spark plug for carbon buildup, fuel fouling, cracked porcelain, loose wire, or incorrect gap.
- Operator-presence control not engaged: Hold the blade-control bail or safety lever firmly against the handle before starting a walk-behind mower.
- Safety switch not engaged: For riding mowers, sit in the seat, set the parking brake, disengage the blades, and place the transmission in the correct position before starting.
Engine Starts but Runs Rough or Stalls
- Dirty air filter: Clean or replace the engine air filter according to the engine manual.
- Old fuel in carburetor: Replace old fuel and inspect the fuel line, fuel filter, and carburetor if the mower has been stored for a long time.
- Carburetor dirty: A clogged jet, varnish deposit, or restricted fuel passage can cause surging, stalling, or hard starting.
- Choke left on: Move the choke to the run position after the engine starts and warms up if your model has manual choke control.
- Grass buildup: Stop the engine, disconnect the spark plug wire, and remove packed grass from the mower deck and engine cooling areas.
Mower Does Not Cut Grass Properly
- Blade is dull: Sharpen or replace the blade if grass tips look torn, ragged, or brown after mowing.
- Blade installed incorrectly: Confirm the cutting edge faces the correct direction and the blade bolt is tightened securely.
- Cutting height too low: Raise the mower deck when cutting tall, thick, wet, or uneven grass.
- Grass is too wet: Wait until the lawn dries to reduce clumping, deck blockage, and uneven cutting.
- Deck clogged: Shut off the engine, remove the ignition key where equipped, disconnect the spark plug wire, 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, stretching, slipping, or breakage.
- Drive wheels worn: Check wheel gears, drive pawls, pinions, and wheel tread for wear or damage.
- Debris in drive system: Remove grass, mud, stones, or string tangled around wheels, pulleys, belts, and drive components.
Riding Mower or Lawn Tractor Will Not Move
- Parking brake engaged: Release the parking brake before attempting to drive.
- Transmission bypass engaged: Check whether the freewheel or hydrostatic bypass lever is in the disengaged position.
- Drive belt damaged: Inspect the transmission drive belt and pulley system for wear, slipping, fraying, or broken components.
- Brake linkage problem: Inspect the brake pedal, linkage, springs, and return mechanism for binding or damage.
- Hydrostatic drive issue: Follow the model-specific procedure for purging air from the hydrostatic transmission if drive feels weak after service or storage.
Blades Will Not Engage
- PTO control not engaged: Pull, press, or move the PTO control fully according to the operating instructions.
- Deck belt worn or broken: Inspect the mower deck belt for cracks, fraying, glazing, stretching, or breakage.
- Safety switch issue: Make sure the operator is seated and all required safety conditions are met.
- PTO clutch or cable problem: Electric PTO clutches and manual blade cables may require adjustment or service if the blades do not engage.
- Deck pulley seized: Inspect spindle pulleys and idler pulleys for noise, wobble, overheating, or restricted movement.
Deck Belt, Pulley and Spindle Problems
- Belt slips off: Check belt routing, pulley alignment, belt guards, idler spring tension, and whether the correct belt size is installed.
- Belt burns or smells hot: Stop the mower and inspect for a seized spindle, locked pulley, jammed blade, or incorrectly routed belt.
- Uneven cutting: Level the mower deck, sharpen blades, check tire pressure, and inspect spindle bearings.
- Deck vibrates: Check for bent blades, loose blade bolts, damaged spindles, worn pulleys, or debris packed under the deck.
- Blade tips hit deck: Inspect blade installation, spindle condition, deck damage, and correct replacement blade length.
Battery, Charging and Electrical Problems
- Starter clicks but engine will not crank: Charge the battery and inspect battery cables, starter solenoid, fuse, starter motor, and ground connection.
- Battery will not hold charge: Check battery age, terminal corrosion, parasitic drain, alternator output, regulator, and wiring connections.
- Headlights not working: Check bulbs, wiring connections, fuse condition, and ignition switch position.
- Blown fuse: Replace only with the correct fuse rating. Repeated blown fuses may indicate a short circuit or damaged wiring.
- Safety interlock issue: Inspect seat switch, brake switch, PTO switch, reverse switch, and wiring connectors if the mower will not crank or blades stop unexpectedly.
Bagging, Mulching and Discharge Problems
- Grass bag not filling: Clean the deck, sharpen blades, check bag airflow, and confirm the discharge path is open.
- Side discharge clogs: Raise the cutting height, mow slower, and clean the discharge chute or opening.
- Mulching is poor: Cut less grass at one time, mow more frequently, and keep blades sharp.
- Clippings clump: Mow dry grass, clean the underside of the deck, and avoid cutting more than one-third of the grass height.
- Uneven clipping pattern: Check blade condition, wheel height settings, tire pressure, deck level, and mowing speed.
Fuel, Oil and Storage Problems
- Fuel smell during storage: Check the fuel cap, fuel line, carburetor, tank, shutoff valve, and filter for leaks.
- Oil smoke from exhaust: Check for overfilled oil, incorrect mower tilting, worn engine components, or oil entering the air filter housing.
- Hard starting after storage: Replace old fuel, clean or replace the spark plug, inspect the air filter, and check the carburetor.
- Fuel system gum deposits: Use fresh fuel and follow the manual's storage procedure before long periods of non-use.
- Oil level changes quickly: Inspect for leaks and check the mower on level ground using the correct dipstick procedure.
Routine Maintenance Tips
- Check engine oil: Inspect the 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, poor tension, or improper routing.
- 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, inspect belts and blades, 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, servicing the drive system, or performing maintenance.