Murray 7800480 Lawn Mower Manual

The Murray 7800480 is a 21-inch push lawn mower featuring a 140cc Briggs & Stratton engine, 3-in-1 mulching/bagging/side discharge capability, single-lever height adjustment, durable steel deck, and easy-start system. This manual covers essential safety instructions, assembly, operation, maintenance, troubleshooting, and storage guidelines to ensure optimal performance and longevity of your mower.

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. Storage Guidelines 9. Warranty Information 10. Troubleshooting

Features at a Glance

Key components: 140cc Briggs & Stratton engine, 21-inch steel cutting deck, rear bagger, mulch plug, side discharge chute, single-lever height adjuster, and push handle.

Feature	Description
Engine	140cc Briggs & Stratton 4-cycle, easy-start system
Cutting Width	21 inches
Cutting Deck	Durable steel construction
Cutting Options	3-in-1: Mulch, Bag, Side Discharge
Height Adjustment	Single-lever, 6 positions (1.5-3.75 inches)
Drive System	Manual push
Starter	Recoil pull-start
Fuel Tank	0.5-gallon capacity
Wheels	8-inch rear, 7-inch front
Weight	Approximately 55 lbs

Assembly Instructions

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

Attach Handle: Insert lower handle into deck brackets, secure with provided bolts and wing nuts.
Install Upper Handle: Connect upper handle section, tighten all fasteners securely.
Attach Bagging System: Hook rear bagger onto deck mounts; ensure chute is properly aligned.
Install Side Discharge Chute: If using side discharge, attach chute to deck opening.
Install Mulch Plug: For mulching, insert plug into rear discharge opening.
Add Engine Oil: Fill with SAE 30 detergent oil (check dipstick for proper level).
Add Fuel: Use fresh unleaded gasoline (minimum 87 octane).

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

Safety Precautions

Read all instructions before operating. Always prioritize safety.

Clear Area: Remove stones, sticks, and debris from lawn before mowing.
Protective Gear: Wear sturdy shoes, long pants, and safety glasses.
Fuel Safety: Refuel outdoors only, with engine off and cool. Wipe spills immediately.
Operation: Do not mow wet grass. Always push mower forward; never pull backward.
Children/Pets: Keep bystanders, especially children and pets, away from area.
Slopes: Mow across slopes, not up and down, to prevent loss of control.
Storage: Store mower in a dry place, away from heat sources and open flame.

CAUTION! Engine and muffler become extremely hot during and after use. Allow to cool before touching or storing.

Specifications

Model: Murray 7800480
Engine: Briggs & Stratton 140cc, 4-cycle, OHV
Cutting Width: 21 inches
Cutting Height: 6 positions, 1.5 to 3.75 inches
Deck Material: Steel
Wheels: 8-inch rear, 7-inch front
Fuel Type: Unleaded gasoline (87 octane minimum)
Oil Type: SAE 30 detergent (summer), check manual for cold weather
Bag Capacity: 1.8 bushels
Warranty: 2-year limited (see warranty card for details)

Controls and Operation

Handle Controls: Throttle lever, primer bulb, recoil starter grip, and blade control bail.

Starting Procedure:

Check oil and fuel levels.
Press primer bulb 3 times (cold engine).
Set throttle to FAST position.
Pull recoil starter grip firmly.
To engage blade, press and hold blade control bail against handle.

Stopping: Release blade control bail to stop blade. Move throttle to STOP position to stop engine.

Operating Tips: Mow at a steady walking pace. Overlap each pass by a few inches for even cut.

Cutting Height Adjustment

Single-lever adjustment for all four wheels.

Stop engine and wait for blade to stop completely.
Pull height adjustment lever toward wheel.
Move lever to desired notch (1=lowest cut, 6=highest cut).
Release lever to lock position.
Check that all wheels are at same height.

Tip: For first mow of season or very tall grass, set to highest setting, then lower for subsequent mows.

Maintenance Schedule

Regular maintenance ensures performance and extends mower life.

Interval	Task
Before each use	Check oil level, inspect blade for damage, clear deck of debris
Every 5 hours	Check air filter, clean if dirty
Every 25 hours	Change engine oil (more frequently in dusty conditions)
Every season	Replace air filter, spark plug, sharpen or replace blade
As needed	Clean underside of deck, check wheel bolts and handle fasteners

Blade Sharpening: Disconnect spark plug wire. Remove blade, sharpen at original angle (balance blade after sharpening).

Storage Guidelines

Proper storage prevents fuel system issues and corrosion.

Run engine to use up fuel in carburetor, or add fuel stabilizer to tank and run for 5 minutes.
Change oil at end of season if due.
Clean mower thoroughly, especially underside of deck.
Remove spark plug, add 1 tablespoon of oil into cylinder, pull starter cord slowly to coat, reinstall plug.
Store in a clean, dry place, covered to protect from dust.

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

Warranty Information

Murray 7800480 is covered by a 2-year limited warranty for residential use. Warranty covers defects in materials or workmanship. Not covered: normal wear, misuse, lack of maintenance, commercial use. Proof of purchase required. For warranty service, contact an authorized Murray service center. For details, visit www.murray.com or call 1-800-XXX-XXXX.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No fuel, old fuel, clogged air filter, spark plug	Check fuel level; use fresh gas. Clean/replace air filter. Check/replace spark plug.
Engine runs poorly	Dirty air filter, old fuel, clogged carburetor	Clean air filter. Drain old fuel. Clean carburetor if needed.
Uneven cutting	Dull blade, uneven tire pressure, deck clogged	Sharpen or replace blade. Check tire pressure. Clean underside of deck.
Excessive vibration	Loose blade, bent blade, debris stuck	Stop engine, disconnect spark plug. Tighten blade bolt. Replace bent blade. Remove debris.
Mower leaves uncut strips	Deck clogged, cutting too low, walking too fast	Clean deck. Raise cutting height. Slow walking pace.

Service: For repairs not covered in manual, contact authorized service center at 1-800-XXX-XXXX or www.murray.com.