Murray 312006X51B Lawn Mower Manual

The Murray 312006X51B is a 21-inch push lawn mower featuring a 6.5 HP Briggs & Stratton engine, 2-in-1 side discharge and mulching capability, 3-position cutting height adjustment, durable steel deck, easy-start system, and rear bagger. Designed for residential use with a cutting width of 21 inches and a 2.1 bushel grass bag. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

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

Features at a Glance

Key components: 6.5 HP Briggs & Stratton engine, 21-inch steel cutting deck, rear grass bag, height adjustment lever, recoil start, and mulching plug.

Feature	Description
Engine	6.5 HP Briggs & Stratton 4-cycle engine
Cutting Width	21 inches
Cutting Options	Side discharge, mulching, bagging
Cutting Height	3-position adjustment (1.5-3.5 inches)
Deck Material	Durable steel construction
Grass Bag Capacity	2.1 bushels
Start System	Recoil pull-start
Wheels	8-inch rear, 7-inch front
Weight	Approximately 65 lbs
Fuel Tank	1-quart capacity

Assembly Instructions

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

Attach handle: Align handle with mounting brackets, secure with provided bolts and wing nuts.
Install grass bag: Hook bag onto rear deck brackets, ensure secure attachment.
Attach mulching plug: Insert plug into discharge chute if mulching desired.
Install wheels: Slide wheels onto axles, secure with retaining clips.
Add engine oil: Fill with SAE 30 detergent oil (check dipstick for level).
Add gasoline: Use fresh unleaded gasoline (no ethanol recommended).

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

First-Time Setup

Before first use, complete pre-operation checks.

Check oil level: Ensure oil is at full mark on dipstick.
Add fuel: Fill tank with fresh unleaded gasoline.
Inspect blade: Ensure blade is sharp and securely fastened.
Adjust cutting height: Set lever to desired position (middle setting recommended).
Test start: Pull recoil starter slowly until resistance felt, then pull briskly.

CAUTION! Operate only in well-ventilated areas. Keep children and pets away during startup.

Specifications

Model: Murray 312006X51B
Engine: 6.5 HP Briggs & Stratton, 4-cycle
Cutting Width: 21 inches
Cutting Height Range: 1.5 to 3.5 inches
Deck Material: 20-gauge steel
Grass Bag Capacity: 2.1 bushels
Wheels: 8-inch rear, 7-inch front
Weight: 65 lbs (approx.)
Fuel Type: Unleaded gasoline (87 octane minimum)
Oil Type: SAE 30 detergent oil (20 oz capacity)

Controls and Operation

Handle Controls: Throttle lever, drive control bar, height adjustment lever.

Starting Procedure:

Move throttle lever to FAST position.
Prime engine (if equipped) by pressing primer bulb 3 times.
Pull recoil starter briskly.
Once started, adjust throttle to desired speed.

Operating Tips: Mow when grass is dry. Overlap passes by 2-3 inches. Empty bag when ¾ full. For mulching, install plug and mow at slower speed.

Cutting Height Adjustment

Adjust cutting height to match grass conditions.

Stop engine and wait for blade to stop completely.
Locate height adjustment lever on each wheel.
Move lever to desired position (1-low, 2-medium, 3-high).
Ensure all four wheels are at same setting.

Recommended Settings: 1.5 inches for Bermuda grass, 2.5 inches for fescue, 3.5 inches for tall weeds.

Maintenance Schedule

Regular maintenance ensures optimal performance.

Interval	Task
Before each use	Check oil level, inspect blade, check for loose parts
Every 25 hours	Change engine oil, clean air filter, check spark plug
Every season	Sharpen or replace blade, clean underside of deck
Storage	Drain fuel or add stabilizer, clean thoroughly

Tip: Always disconnect spark plug wire before performing maintenance.

Safety Features

Blade brake system: Stops blade within 3 seconds when handle is released. Safety key: Must be inserted to start engine. Discharge guard: Prevents debris ejection.

Safety Rules: Wear eye protection and sturdy shoes. Clear mowing area of debris. Never mow on slopes greater than 15 degrees. Do not remove safety devices.

Storage & Winterization

Prepare mower for off-season storage.

Drain fuel: Run engine until tank is empty, or add fuel stabilizer.
Change oil: Replace with fresh oil to prevent corrosion.
Clean: Remove grass clippings from deck and underside.
Remove spark plug: Add teaspoon of oil to cylinder, pull starter slowly.
Store: Keep in dry, covered area, preferably on blocks to protect tires.

CAUTION! Never store with gasoline in tank for more than 30 days without stabilizer.

Warranty Information

Murray offers a 2-year limited warranty for residential use. Warranty covers defects in materials and workmanship. Not covered: normal wear, improper maintenance, commercial use. For warranty claims, contact Murray customer service at 1-800-800-7310 or visit www.murray.com. Keep original receipt as proof of purchase.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No fuel, old gas, clogged filter	Add fresh fuel, clean/replace air filter, check spark plug.
Poor cutting performance	Dull blade, low engine speed	Sharpen or replace blade, adjust throttle to FAST.
Vibration	Loose blade, unbalanced blade	Tighten blade bolt, replace bent blade.
Engine stalls	Clogged deck, grass too wet	Clean underside of deck, wait for drier conditions.
Won't mulch properly	Wet grass, dull blade, speed too fast	Mow when dry, sharpen blade, slow mowing speed.

Service: For repairs, use authorized service centers. Always use genuine Murray parts.

Support: 1-800-800-7310; www.murray.com