Murray 405327X51 Lawn Mower Manual

The Murray 405327X51 is a 21-inch push lawn mower featuring a 190cc Briggs & Stratton engine, 3-in-1 mulching, bagging, and side discharge capability, 6-position single-lever height adjustment, durable steel deck, easy-start system, and rear-wheel drive. This manual covers essential safety instructions, assembly, operation, maintenance, troubleshooting, and storage procedures to ensure optimal performance and longevity.

1. Features at a Glance 2. Assembly Instructions 3. Safety Precautions 4. Specifications 5. Controls and Operation 6. Cutting Height Adjustment 7. Maintenance Schedule 8. Blade Care & Sharpening 9. Storage & Winterization 10. Warranty Information 11. Troubleshooting

Features at a Glance

Key components: 190cc Briggs & Stratton engine, 21-inch steel cutting deck, rear bagger, mulch plug, side discharge chute, single-lever height adjustment, rear-wheel drive system, and easy-start primer bulb.

Feature	Description
Engine	190cc Briggs & Stratton 4-cycle engine
Cutting Width	21 inches
Cutting Options	3-in-1 (Mulch, Bag, Side Discharge)
Height Adjustment	Single-lever, 6 positions (1.5" - 4")
Drive System	Rear-wheel drive
Deck Material	Durable steel
Fuel Tank Capacity	1.1 quarts
Wheel Size	8-inch rear, 7-inch front
Starting System	Recoil starter with primer bulb
Weight	Approximately 65 lbs

Assembly Instructions

Unpack all parts from box. Assembly requires basic tools (included).

Attach handle: Align lower handle with deck brackets, secure with provided bolts and washers.
Install upper handle: Connect to lower handle, tighten knobs securely.
Attach grass bag: Hook bag frame onto rear deck brackets, ensure it locks in place.
Install side discharge chute: Slide into opening on right side of deck, secure with wing nut.
Add engine oil: Remove oil fill cap/dipstick, add 20 oz SAE 30 detergent oil (not included).
Add fuel: Use fresh unleaded gasoline with minimum 87 octane. Do not overfill.

WARNING! Always wear gloves during assembly. Ensure all fasteners are tight before operation.

Safety Precautions

Read all instructions before operating. Failure to follow safety rules may result in serious injury.

Clear mowing area of stones, sticks, wire, and other objects that could be thrown.
Always wear substantial footwear and long pants. Do not operate barefoot or in sandals.
Do not mow in reverse unless absolutely necessary. Always look down and behind.
Never allow children or untrained persons to operate mower.
Stop engine and disconnect spark plug wire before clearing blockages or performing maintenance.
Do not operate on slopes greater than 15 degrees. Mow across slopes, not up and down.
Fuel outdoors only. Do not smoke near fuel or engine.

DANGER! Rotating blade can cause severe injury. Keep hands and feet away from deck at all times.

Specifications

Model: Murray 405327X51
Engine: Briggs & Stratton 190cc, 4-cycle, OHV
Cutting Width: 21 inches
Cutting Height Range: 1.5 - 4 inches (6 positions)
Deck Material: 20-gauge steel
Drive System: Rear-wheel drive
Wheels: 8-inch rear, 7-inch front
Fuel Type: Unleaded gasoline (87 octane minimum)
Oil Type: SAE 30 detergent (20 oz capacity)
Bag Capacity: 2.1 bushels
Warranty: 2-year limited

Controls and Operation

Handle Controls: Drive control bar (must be held to propel mower), height adjustment lever, primer bulb, throttle control, recoil starter handle.

Starting Procedure:

Check oil and fuel levels.
Move throttle control to FAST position.
Press primer bulb 3 times (cold engine).
Hold drive control bar against handle.
Pull recoil starter briskly.

Stopping: Release drive control bar, move throttle to STOP. For emergency stop, release all controls.

Cutting Mode Selection: Install mulch plug for mulching, grass bag for collection, or side discharge chute for discharging.

Cutting Height Adjustment

Single-lever adjustment changes height for all four wheels simultaneously.

Stop engine and wait for blade to stop completely.
Pull height adjustment lever outward and move to desired position (1-6).
Release lever to lock in position.
Recommended heights: 2.5-3 inches for most grasses, higher for rough terrain.

Tip: Never adjust height while engine is running. Always mow at highest setting when cutting tall grass.

Maintenance Schedule

Maintenance Task	Frequency
Check engine oil level	Before each use
Clean underside of deck	After each use
Check blade for sharpness/damage	Every 25 hours
Change engine oil	First 5 hours, then every 50 hours
Replace air filter	Every 25 hours (more often in dusty conditions)
Replace spark plug	Every 100 hours
Lubricate wheels and height adjustment	Every 25 hours
Check drive system tension	Every 50 hours

CAUTION! Always disconnect spark plug wire before performing any maintenance.

Blade Care & Sharpening

A sharp blade ensures clean cuts and healthy grass.

Disconnect spark plug wire and tip mower on side (carburetor side up).
Use block of wood to prevent blade from turning while removing bolt.
Remove blade and inspect for damage (cracks, bends, excessive wear). Replace if damaged.
Sharpen blade maintaining original cutting angle. Remove equal amount from both ends.
Balance blade by placing on nail or blade balancer. File heavy end until balanced.
Reinstall blade with cutting edge toward ground. Torque to 450-600 in-lbs.

WARNING! Always wear heavy gloves when handling blade. Replace damaged blades immediately.

Storage & Winterization

Proper storage extends mower life.

Run engine to warm oil, then drain completely (or use fuel stabilizer).
Remove spark plug and add 1 oz of oil through spark plug hole. Pull starter slowly to distribute oil.
Clean entire mower, especially underside of deck.
Sharpen and balance blade.
Store in clean, dry place. Cover with breathable material.
For long-term storage, remove battery (if equipped) and store separately.

CAUTION! Never store mower with fuel in tank indoors or in enclosed spaces.

Warranty Information

Murray 405327X51 includes a 2-year limited warranty covering defects in materials and workmanship under normal residential use. Warranty does not cover damage from misuse, neglect, commercial use, or improper maintenance. Proof of purchase required. For warranty service, contact authorized Murray service center or call 1-800-800-7310. Keep this manual and purchase receipt for warranty validation.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Empty fuel tank, stale fuel, clogged air filter, spark plug wire disconnected	Add fresh fuel, replace air filter, ensure spark plug wire connected, check oil level
Engine runs poorly	Dirty air filter, old fuel, water in fuel, clogged fuel line	Clean/replace air filter, drain and replace fuel, check fuel lines
Uneven cutting	Dull blade, uneven tire pressure, deck clogged	Sharpen/replace blade, inflate tires evenly, clean deck underside
Mower vibrates excessively	Loose blade, bent blade, unbalanced blade	Tighten blade bolt, replace bent blade, balance blade
Loss of power	Clogged deck, dull blade, drive belt worn	Clean deck, sharpen blade, inspect/replace drive belt
Wheels not driving	Drive control cable loose, drive belt worn	Adjust drive control cable tension, replace drive belt
Grass not discharging properly	Wet grass, engine speed too low, deck clogged	Mow when grass dry, run at full throttle, clean deck

Service: For repairs beyond basic maintenance, contact authorized Murray service center at 1-800-800-7310 or visit www.murray.com.