Murray 7800890 Lawn Mower Manual

The Murray 7800890 is a walk-behind, self-propelled gasoline lawn mower featuring a Briggs & Stratton engine, 21-inch steel cutting deck, single-lever height adjustment, rear bagging system, and mulching capability. It includes safety features like a blade control handle, operator presence control, and a durable steel chassis. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

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

Features at a Glance

Key components: Briggs & Stratton engine, 21-inch steel deck, Rear bagger, Single-lever height adjustment, Self-propelled drive system, Blade control handle.

Feature	Description
Engine	Briggs & Stratton 125cc gasoline engine
Cutting Width	21 inches
Cutting Deck	Durable steel construction
Drive System	Self-propelled, rear-wheel drive
Height Adjustment	Single-lever, 6 positions (1.5-3.5 inches)
Collection System	Rear bagging with 2-bushel capacity
Mulching Capability	Optional mulching kit (sold separately)
Blade Control	Operator presence control system
Wheels	8-inch rear, 7-inch front
Fuel Tank	0.5-gallon capacity

Assembly & Setup

Unpack and inspect all parts. Assembly requires basic tools.

Attach handle: Secure upper and lower handle sections with provided bolts.
Install bagger: Connect rear bagger frame to deck; attach collection bag.
Add engine oil: Fill with SAE 30 detergent oil (check dipstick).
Add gasoline: Use fresh unleaded gasoline (87 octane minimum).
Check tire pressure: Inflate to 15 PSI.

WARNING! Keep hands and feet clear of cutting deck during assembly. Ensure all fasteners are tight.

Safety Instructions

Read all instructions before operation. Always wear protective equipment.

Clear mowing area: Remove stones, toys, and other objects.
Check blade: Ensure blade is sharp and securely fastened.
Start engine outdoors only: Never in enclosed spaces.
Use blade control: Keep handle engaged for blade rotation.
Stop engine: Before unclogging, adjusting, or crossing gravel drives.

CAUTION! Do not mow wet grass. Keep children and pets away from mowing area.

Specifications

Model: Murray 7800890
Engine: Briggs & Stratton 125cc, 4-cycle
Cutting Width: 21 inches
Cutting Heights: 6 positions, 1.5 to 3.5 inches
Drive: Self-propelled, single-speed
Bag Capacity: 2 bushels
Deck Material: Steel
Warranty: 2-year limited
Weight: 65 lbs (approx.)

Controls and Operation

Handle Controls: Blade control handle, Drive control lever, Height adjustment lever.

Starting: 1. Push primer bulb 3 times. 2. Set throttle to FAST. 3. Pull recoil starter.

Self-Propelled Operation: Squeeze drive control lever to handle to engage wheels.

Stopping: Release blade control handle; engine and blade will stop. Set throttle to STOP.

Cutting Height Adjustment

Use single lever to adjust all four wheels simultaneously.

Stop engine and wait for blade to stop completely.
Pull height adjustment lever outward and move to desired position.
Release lever to lock into position.
Test mower stability on flat surface before mowing.

Tip: For first mow of season, set to highest setting; gradually lower for subsequent mows.

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

Interval	Task
Before each use	Check oil level; inspect blade for damage; clear deck of debris
Every 25 hours	Change engine oil; clean or replace air filter
Every season	Sharpen or replace blade; check spark plug; lubricate wheels
As needed	Clean underside of deck; check tire pressure; inspect drive belt

WARNING! Disconnect spark plug wire before performing any maintenance.

Storage Instructions

Prepare mower for off-season storage to prevent damage.

Drain fuel tank or add fuel stabilizer.
Change engine oil.
Clean entire mower, especially underside of deck.
Store in dry, covered area.
Remove spark plug and add 1 tablespoon of oil to cylinder; pull starter slowly to coat.

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

Warranty Information

Murray 7800890 is covered by a 2-year limited warranty for residential use. Warranty covers defects in materials and workmanship. Not covered: normal wear, misuse, commercial use, improper maintenance. For warranty service, contact authorized service center with proof of purchase.

Parts Diagram

Refer to exploded-view diagram for part numbers and assembly reference. Common replacement parts: Blade (part #94287), Air filter (part #491588), Drive belt (part #754-04050), Spark plug (RC12YC).

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No fuel, old gasoline, clogged filter	Add fresh fuel; check fuel line; clean/replace air filter.
Poor cutting performance	Dull blade, low engine speed	Sharpen or replace blade; set throttle to FAST.
Mower vibrates excessively	Unbalanced blade, loose parts	Stop engine, check blade balance and tightness; secure all fasteners.
Self-propelled drive not working	Drive belt worn or off pulley	Inspect drive belt; replace if frayed or broken.
Grass not discharging properly	Wet grass, clogged deck	Mow when grass is dry; stop engine and clean deck underside.

Service: For technical support, call 1-800-800-7310 or visit www.murray.com