Murray 425003X8A Lawn Mower Manual

The Murray 425003X8A is a walk-behind, self-propelled gasoline lawn mower featuring a Briggs & Stratton engine, 21-inch cutting deck, 3-in-1 mulch/bag/side-discharge capability, single-lever height adjustment, and rear-wheel drive. This manual covers essential safety instructions, assembly, operation, maintenance, troubleshooting, and storage procedures to ensure optimal performance and longevity of your mower.

1. Safety Instructions 2. Assembly & Setup 3. Controls & Features 4. Specifications 5. Operation 6. Maintenance Schedule 7. Engine Care 8. Blade Care & Sharpening 9. Storage 10. Troubleshooting 11. Warranty & Support

Safety Instructions

Always read and understand the manual before operating. Key safety components: Engine ON/OFF switch, Blade Control Lever, Drive Control Lever, Height Adjustment Lever.

Hazard	Precaution
Rotating Blade	Keep hands and feet away from deck. Disconnect spark plug before servicing.
Fuel Handling	Refuel outdoors, engine off and cool. Use fresh gasoline only.
Slope Operation	Mow across slopes, not up and down. Use caution on inclines over 15°.
Thrown Objects	Clear area of debris before mowing. Wear eye protection.
Hot Surfaces	Avoid contact with muffler and engine during/after operation.
Children & Pets	Keep clear of mowing area. Never allow children to operate.

Assembly & Setup

Unpack and inspect all parts. Assembly requires basic tools (included).

Attach Handle: Align lower handle with deck brackets, secure with provided bolts and wing nuts.
Install Bagging System: Attach rear bagger to deck hooks; connect chute if mulching plug not used.
Add Engine Oil: Check oil level; add SAE 30 detergent oil as specified (approx. 20 oz).
Add Fuel: Fill tank with fresh unleaded gasoline (max 1.2 quarts).
Check Tire Pressure: Inflate to 15 PSI (front) and 10 PSI (rear).

WARNING! Do not start engine until assembly is complete and all fasteners are tight.

Controls & Features

Front Panel: Engine ON/OFF switch, Recoil Starter, Primer Bulb. Handle: Blade Control Lever, Drive Control Lever, Height Adjustment Lever.

Key Functions: Blade Control Lever must be held against handle to engage blade and self-propel drive. Drive Control Lever adjusts speed (1-5). Height Adjustment Lever sets cutting height (1.5-3.75 inches).

Deck Features: 3-in-1 capability (mulch plug, rear bag, side discharge). Engine: Briggs & Stratton 125cc OHV with easy-start system.

Specifications

Model: Murray 425003X8A
Engine: Briggs & Stratton 125cc, 4-cycle OHV
Cutting Width: 21 inches
Cutting Heights: 6 positions (1.5" to 3.75")
Drive System: Self-propelled, rear-wheel drive
Speed Settings: 5 forward speeds, no reverse
Deck Material: Steel, 3-in-1 design
Fuel Capacity: 1.2 quarts (unleaded gasoline)
Oil Capacity: 20 oz (SAE 30 detergent)
Warranty: 2-year limited

Operation

Starting, mowing, and stopping procedures.

Pre-Start: Check oil and fuel. Set height lever. Clear mowing area.
Starting: Push primer bulb 3 times. Set throttle to FAST. Pull recoil starter firmly.
Engaging Blade/Drive: Hold Blade Control Lever against handle. Squeeze Drive Control Lever to desired speed.
Mowing: Overlap passes by 2-3 inches. Avoid mowing wet grass.
Stopping: Release Drive Control, then Blade Control. Move throttle to STOP.
Emptying Bag: Stop engine. Lift rear flap to empty clippings.

Tip: For best cut, mow when grass is dry and keep blade sharp.

Maintenance Schedule

Interval	Task
Before each use	Check oil level, tire pressure, blade condition, clear deck of debris.
Every 25 hours	Change engine oil (or annually). Check/replace air filter.
Every 50 hours	Replace spark plug. Inspect drive belt for wear.
Every season	Sharpen or replace blade. Clean underside of deck. Lubricate wheel axles.
Storage	Drain fuel or add stabilizer. Remove battery (if electric start model).

Engine Care

Briggs & Stratton 125cc maintenance.

Oil Change: Run engine to warm oil. Drain via dipstick tube. Refill with SAE 30 (20 oz).
Air Filter: Remove foam pre-filter, wash in soapy water, dry, and re-oil lightly. Replace paper filter if dirty.
Spark Plug: Gap at 0.030 inches. Replace annually (Champion RC12YC).
Fuel System: Use fresh gasoline (87 octane). Add fuel stabilizer for storage over 30 days.

CAUTION! Engine is hot after operation. Allow to cool before servicing.

Blade Care & Sharpening

Balanced blade is critical for smooth operation.

Remove Blade: Disconnect spark plug. Tip mower (carburetor side up). Use block to secure blade, remove bolt.
Sharpen: File cutting edge at original angle (approx. 30°). Remove equal metal from both ends.
Balance: Hang blade on nail; if one side dips, file heavy end until balanced.
Reinstall: Torque blade bolt to 450 in-lb (37.5 ft-lb). Reconnect spark plug.

WARNING! Always wear gloves when handling sharp blade.

Storage

End-of-season preparation.

Fuel: Run engine dry or add fuel stabilizer and run 5 minutes to circulate.
Oil: Change oil if not done recently.
Blade: Sharpen and coat with light oil.
Clean: Wash deck (avoid engine), dry thoroughly.
Store: In dry, covered area. Cover mower to keep dust-free.

CAUTION! Never store with fuel in tank untreated; gumming may occur.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No fuel, old gas, clogged filter, bad spark plug	Check fuel; use fresh gas. Clean/replace air filter. Check spark plug.
Engine runs poorly	Dirty air filter, old fuel, water in gas	Clean air filter. Drain fuel tank, refill with fresh gas.
Uneven cut	Dull blade, uneven tire pressure, deck clogged	Sharpen blade. Inflate tires evenly. Clean deck underside.
Loss of power	Clogged deck, dirty filter, low oil	Clean deck. Replace air filter. Check oil level.
Self-propel not working	Drive belt loose/worn, control cable misadjusted	Inspect belt; replace if cracked. Adjust drive cable tension.
Excessive vibration	Unbalanced blade, loose blade bolt, debris in deck	Balance or replace blade. Tighten blade bolt. Clean deck.

Reset: For safety switches, ensure Blade Control Lever is fully engaged.

Service: For repairs, contact authorized Murray service center or call 1-800-800-7310.

Warranty & Support

Murray 425003X8A is covered by a 2-year limited warranty for residential use. Proof of purchase required. Warranty does not cover normal wear, misuse, or commercial use. For parts, manuals, or support:

Website: www.murray.com
Customer Service: 1-800-800-7310
Parts Lookup: Use model number 425003X8A