Manual for Craftsman M320 Mower

The Craftsman M320 is a 21-inch self-propelled gas lawn mower featuring a 159cc Briggs & Stratton engine, 3-in-1 mulching/bagging/side discharge capability, single-lever height adjustment (6 positions), 2.1 bushel rear bag, and electric start with backup pull cord. Key sections cover safety, assembly, operation, maintenance, troubleshooting, and specifications.

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

Features at a Glance

Key components: 159cc Briggs & Stratton engine, 21-inch steel deck, rear bag, self-propelled drive system, electric start, single-lever height adjustment.

Feature	Description
Engine	159cc Briggs & Stratton 450E Series, OHV
Cutting Width	21 inches
Cutting Height	6 positions (1.25-3.75 inches)
Drive System	Self-propelled, variable speed
Start System	Electric start with backup recoil
Discharge Options	Mulch, Bag, Side Discharge
Bag Capacity	2.1 bushels
Wheels	8-inch rear, 7-inch front
Deck Material	Steel
Fuel Tank	0.95 gallons

Assembly Instructions

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

Attach handle: Secure upper and lower handle sections with provided bolts.
Install bag: Attach rear bag assembly to deck hooks.
Connect battery: For electric start, connect battery terminals (red to positive).
Add oil and fuel: Fill engine with SAE 30 oil; add fresh unleaded gasoline (87 octane).
Install mulch plug (if mulching): Insert plug into side discharge chute.

WARNING! Wear gloves during assembly. Ensure all bolts are tightened securely.

First-Time Setup

Prepare mower for initial use.

Check oil level: Dipstick should show full.
Add fuel: Use fresh unleaded gasoline; do not overfill.
Adjust cutting height: Set lever to desired position (middle setting recommended).
Test start: Use electric start (battery charged) or pull cord.
Engage drive: Squeeze drive control lever to test self-propelled function.

CAUTION! Operate outdoors only. Keep clear of bystanders during start-up.

Specifications

Model: Craftsman M320
Engine: 159cc Briggs & Stratton 450E Series, OHV
Cutting Width: 21 inches
Cutting Height Range: 1.25-3.75 inches (6 positions)
Drive: Self-propelled, variable speed (0-3.2 mph)
Start System: Electric (12V battery) with backup recoil
Bag Capacity: 2.1 bushels
Fuel Capacity: 0.95 gallons
Oil Capacity: 20 oz (SAE 30)
Weight: 78 lbs (approx.)

Controls and Operation

Main controls: Drive control lever, height adjustment lever, electric start button, recoil starter, throttle control, blade engagement lever.

Starting: For electric start, turn key (if equipped) or press button. For recoil, pull cord briskly.

Self-propelled operation: Squeeze drive control lever to engage; release to stop. Adjust speed with throttle.

Cutting height: Move single lever to one of 6 positions.

Blade engagement: Pull lever against handle to engage blade; release to stop.

Cutting & Discharge Options

3-in-1 system: Mulching, Bagging, Side Discharge.

Mulching: Install mulch plug; grass clippings cut finely and returned to lawn.
Bagging: Attach rear bag; clippings collected for disposal.
Side Discharge: Remove mulch plug and bag; clippings discharged to side.

Tip: For best mulching, mow when grass is dry and not too tall.

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

Interval	Task
Before each use	Check oil level, inspect blade, clear deck of debris
Every 25 hours	Change oil (SAE 30), clean/replace air filter
Every season	Sharpen or replace blade, check spark plug
As needed	Clean underside of deck, check tire pressure
Storage	Drain fuel or add stabilizer, disconnect battery

WARNING! Disconnect spark plug before performing any maintenance.

Storage Guidelines

Prepare mower for off-season storage.

Clean thoroughly: Remove grass clippings from deck and undercarriage.
Fuel management: Either drain tank completely or add fuel stabilizer.
Battery: Disconnect and store in cool, dry place; charge periodically.
Store indoors: Keep in dry, covered area; protect from moisture.

CAUTION! Never store mower with fuel in tank near open flames or heat sources.

Safety Information

Read and follow all safety instructions in manual.

Wear appropriate clothing: long pants, sturdy shoes, eye protection.
Clear mowing area of debris, stones, and toys before operation.
Never mow wet grass or on steep slopes.
Keep hands and feet away from moving parts and discharge chute.
Always turn off engine and disconnect spark plug before maintenance.
Do not allow children to operate mower.

Warranty & Support

Craftsman M320 comes with a 2-year limited warranty covering defects in materials and workmanship. Warranty does not cover normal wear, misuse, or lack of maintenance. For support, contact Craftsman Customer Service at 1-888-331-4569 or visit www.craftsman.com. Have model number (M320) and serial number ready when calling.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Empty fuel tank, old gasoline, spark plug	Add fresh fuel; check spark plug; ensure battery charged (electric start).
Poor cutting performance	Dull blade, clogged deck, low engine speed	Sharpen/replace blade; clean deck; adjust throttle to full speed.
Self-propelled not working	Drive belt loose, control cable	Check drive belt tension; inspect control cable connection.
Excessive vibration	Damaged blade, loose parts	Stop engine immediately; inspect blade for damage; tighten all bolts.
Bag not filling	Wet grass, clogged chute	Mow when grass dry; clear discharge chute of debris.

Reset: For electric start models, check battery connection if system is unresponsive.

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