Murray MNA 153003 Lawn Mower Manual

The Murray MNA 153003 is a 3.5 HP, 21-inch push lawn mower featuring a Briggs & Stratton engine, 2-in-1 side discharge/mulching capability, 6-position single-lever height adjustment, durable steel deck, easy-start system, and large rear wheels for maneuverability. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Assembly Instructions 3. Safety Information 4. Specifications 5. Controls and Operation 6. Cutting Height Adjustment 7. Maintenance Schedule 8. Storage Instructions 9. Warranty Information 10. Troubleshooting

Features at a Glance

Key components: Briggs & Stratton 3.5 HP engine, 21-inch steel cutting deck, 2-in-1 discharge system, single-lever height adjustment, rear-wheel drive, and fold-down handle.

Feature	Description
Engine	Briggs & Stratton 3.5 HP, 4-cycle, single-cylinder
Cutting Width	21 inches
Cutting System	2-in-1 side discharge and mulching
Height Adjustment	Single-lever, 6 positions (1.0-3.5 inches)
Deck Material	Durable steel construction
Wheels	Large 8-inch rear wheels for easy maneuverability
Starter	Recoil easy-start system
Fuel Tank	0.5-gallon capacity
Handle	Fold-down for compact storage
Weight	Approximately 55 lbs

Assembly Instructions

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

Attach handle: Secure upper and lower handle sections with provided bolts and wing nuts.
Install wheels: Slide wheels onto axles and secure with retainer clips.
Attach discharge chute: Align chute with deck opening and secure with wing nut.
Install mulching plug (if using mulching mode): Insert into discharge opening.
Add oil and fuel: Fill engine with SAE 30 oil (20 oz) and unleaded gasoline.

WARNING! Always wear gloves during assembly. Ensure all bolts are tightened securely.

Safety Information

Read all instructions before operation. Always wear appropriate safety gear.

Clear mowing area of debris, rocks, and toys before starting.
Never operate without discharge chute or mulching plug properly installed.
Keep hands and feet away from moving parts and discharge area.
Do not mow on steep slopes or wet grass.
Always stop engine and remove spark plug wire before performing maintenance.

DANGER! Gasoline is flammable. Refuel outdoors with engine off and cool.

Specifications

Model: MNA 153003
Engine: Briggs & Stratton 3.5 HP, 4-cycle
Cutting Width: 21 inches
Cutting Heights: 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 inches
Deck: 21-inch steel, 2-in-1 discharge/mulching
Wheels: 8-inch rear, 7-inch front
Fuel Capacity: 0.5 gallons
Oil Capacity: 20 oz SAE 30
Weight: 55 lbs (approx.)
Warranty: 2-year limited

Controls and Operation

Handle Controls: Drive control bar, height adjustment lever, throttle control.

Starting: 1. Check oil and fuel levels. 2. Push primer bulb 3 times. 3. Set throttle to FAST. 4. Pull recoil starter firmly.

Stopping: Release drive control bar, move throttle to STOP, wait for blade to stop.

Operation: Engage drive control bar to propel mower. Release to stop movement. Adjust speed with throttle.

Cutting Height Adjustment

Single-lever adjustment for all four wheels simultaneously.

Stop engine and wait for blade to stop completely.
Pull height adjustment lever outward.
Move lever to desired position (1-6).
Release lever to lock in position.
Test on small area before full mowing.

Tip: For first mow of season, set to highest position. Gradually lower for subsequent mows.

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

Maintenance	Frequency	Procedure
Check oil level	Before each use	Use dipstick; add SAE 30 if low
Air filter cleaning	Every 25 hours	Remove foam filter, wash in soapy water, dry, re-oil
Spark plug	Every season	Clean and gap to 0.030 inches
Blade sharpening	Every 25 hours	Remove blade, sharpen at 30-degree angle, balance
Undercarriage cleaning	After each use	Scrape off grass buildup with putty knife

CAUTION! Always disconnect spark plug before performing maintenance.

Storage Instructions

Proper storage prevents damage and extends mower life.

Drain fuel tank or add fuel stabilizer.
Run engine until it stops to clear carburetor.
Change oil if near end of season.
Clean entire mower, especially undercarriage.
Store in dry, covered area, preferably off concrete floor.
Fold handle down for compact storage.

WARNING! Never store mower with fuel in tank indoors or near open flame.

Warranty Information

Murray MNA 153003 comes with a 2-year limited warranty covering defects in materials and workmanship. Warranty does not cover normal wear, misuse, or improper maintenance. Proof of purchase required. For warranty service, contact Murray customer service at 1-800-XXX-XXXX or visit www.murray.com.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Empty fuel tank, old gasoline, clogged air filter	Add fresh unleaded fuel; clean/replace air filter; check spark plug
Engine runs poorly	Dirty air filter, old fuel, water in fuel	Clean air filter; drain and replace fuel; check fuel lines
Uneven cutting	Dull blade, uneven tire pressure, incorrect height setting	Sharpen blade; inflate tires evenly; adjust cutting height
Excessive vibration	Loose blade, bent blade, debris under deck	Tighten blade bolt; replace bent blade; clean undercarriage
Mower doesn't propel	Drive cable loose or broken, drive belt worn	Adjust drive cable tension; replace drive belt if necessary

Service: For technical support, call 1-800-XXX-XXXX or visit www.murray.com