Craftsman 21 Mulcher Lawn Mower Manual

The Craftsman 21 Mulcher Lawn Mower is a 21-inch walk-behind mower featuring a Briggs & Stratton engine, 3-in-1 mulching/bagging/side-discharge capability, adjustable cutting heights (1.25-3.75 inches), easy-start system, durable steel deck, rear-wheel drive, and ergonomic handle with controls. Designed for residential lawns up to 1/2 acre. Below are key sections for safety, features, assembly, operation, maintenance, troubleshooting, and specifications.

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

Features at a Glance

Key components: 21-inch steel cutting deck, Briggs & Stratton 140cc engine, 3-in-1 mulch/bag/side-discharge system, 6-position height adjustment, rear-wheel drive, ergonomic handle, washout port, and grass bag with indicator.

Feature	Description
Cutting Width	21 inches
Engine	Briggs & Stratton 140cc, 4-cycle
Cutting System	3-in-1 (Mulch/Bag/Side Discharge)
Cutting Height Adjustment	6 positions (1.25" - 3.75")
Drive System	Rear-wheel drive
Deck Material	Powder-coated steel
Start Type	Recoil start with primer bulb
Grass Bag Capacity	2.0 bushels
Handle	Ergonomic, foldable for storage
Washout Port	For easy deck cleaning

Assembly Instructions

Unpack and inspect all parts. Assembly requires adjustable wrench and screwdriver.

Attach handle: Align lower handle with deck brackets, secure with provided bolts and washers.
Install upper handle: Connect to lower handle, secure knobs or bolts.
Attach grass bag: Hook bag frame onto rear deck brackets; ensure secure fit.
Install mulch plug: Insert into rear discharge chute for mulching mode.
Check wheels: Ensure all wheels are securely attached and rotate freely.
Add oil and fuel: Fill engine with SAE 30 oil (check dipstick); add fresh unleaded gasoline.

WARNING! Do not add fuel indoors or near ignition sources. Wear gloves during assembly.

Safety Information

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

Clear mowing area: Remove stones, toys, and debris.
Check equipment: Inspect for loose parts or damage before each use.
Fuel safety: Refuel outdoors, engine off and cool. Wipe spills.
Operation: Do not mow wet grass. Keep hands and feet away from moving parts.
Children/pets: Keep clear of mowing area. Never allow children to operate.
Slopes: Mow across slopes, not up and down, to prevent tipping.

CAUTION! Disconnect spark plug wire before performing any maintenance.

Specifications

Model: Craftsman 21" Mulcher Lawn Mower
Engine: Briggs & Stratton 140cc, 4-cycle, OHV
Cutting Width: 21 inches
Cutting Heights: 1.25", 1.75", 2.25", 2.75", 3.25", 3.75"
Drive: Rear-wheel drive
Deck: 21-inch steel, powder-coated
Start System: Recoil with primer bulb
Fuel Tank: 0.5 gallons
Oil Capacity: 20 oz (SAE 30)
Weight: 65 lbs (approx.)
Warranty: 2-year limited

Controls and Operation

Handle controls: Drive control lever, height adjustment lever, engine stop cable.

Starting: 1. Check oil and fuel. 2. Prime engine (3-5 presses). 3. Set throttle to FAST. 4. Pull recoil starter firmly.

Stopping: Release drive lever; move throttle to STOP; disconnect spark plug for storage.

Driving: Squeeze drive lever against handle to engage wheels; release to stop drive.

Bagging/Mulching: Install bag or mulch plug as needed; ensure chute is clear.

Cutting Height Adjustment

Adjust all four wheels evenly for level cut.

Locate height adjustment lever on each wheel.
Pull lever outward and move to desired height setting (1-6).
Ensure all levers are set to same position.
Test mow a small area to verify cut quality.

Tip: Higher settings for tall grass; lower for fine lawns. Never remove more than 1/3 of grass height at once.

Mulching & Bagging Setup

3-in-1 system allows quick conversion.

Mulching: Install mulch plug in rear discharge chute. Ensure bag is removed.
Bagging: Remove mulch plug; attach grass bag to rear brackets.
Side Discharge: Remove both mulch plug and bag; attach side discharge chute (if included).
Check that all attachments are secure before operation.

WARNING! Always stop engine and disconnect spark plug before changing cutting modes.

Maintenance Schedule

Interval	Task
Before each use	Check oil level; inspect for damage; clear deck of debris
Every 5 hours	Check blade sharpness and balance
Every 25 hours	Change engine oil; clean/replace air filter
Every season	Sharpen or replace blade; check spark plug
As needed	Clean underside of deck; lubricate wheel axles

Blade Sharpening: Remove blade; sharpen at original angle (22°). Balance before reinstalling.

Storage & Winterization

Prepare mower for off-season storage.

Clean thoroughly: Remove grass clippings from deck, wheels, and engine.
Fuel: Run engine until tank is empty, or add fuel stabilizer.
Oil: Change oil if near service interval.
Blade: Sharpen and coat with light oil to prevent rust.
Storage: Store in dry, covered area; fold handle if possible.

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

Warranty Information

Craftsman 21 Mulcher Lawn Mower includes a 2-year limited warranty covering defects in materials/workmanship. Warranty does not cover normal wear, misuse, or lack of maintenance. Proof of purchase required. For warranty service, contact Craftsman Customer Support at 1-888-331-4569 or visit www.craftsman.com.

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 spark plug.
Poor cut quality	Dull blade; incorrect height; wet grass	Sharpen blade; adjust cutting height; mow when grass is dry.
Uneven cutting	Uneven tire pressure; deck not level	Check tire pressure; level deck using adjustment levers.
Excessive vibration	Loose blade; bent blade; debris	Tighten blade bolt; replace bent blade; clean deck.
Loss of power	Clogged deck; dirty air filter	Clean underside of deck; replace air filter.
Wheels not driving	Drive cable loose; worn drive belt	Adjust drive cable tension; replace drive belt if worn.

Service: For repairs, contact authorized Craftsman service center. Use only genuine parts.

Support: 1-888-331-4569; www.craftsman.com