Craftsman Lawn Mower Model 917.378941 Manual

The Craftsman Model 917.378941 is a 21-inch self-propelled gas lawn mower featuring a 190cc Briggs & Stratton engine, 3-in-1 mulching/bagging/side-discharge capability, single-lever height adjustment (1.25-3.75 inches), 2-gallon grass bag, rear-wheel drive, and easy-start system. This manual covers safety, assembly, operation, maintenance, troubleshooting, and specifications. Always read instructions before use.

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. Engine Care 9. Storage Guidelines 10. Warranty Information 11. Troubleshooting

Features at a Glance

Key components: 190cc Briggs & Stratton engine, 21-inch steel deck, rear bagger, self-propelled drive system, single-lever height adjustment, 3-in-1 functionality.

Feature	Description
Engine	190cc Briggs & Stratton, 4-cycle, OHV
Cutting Width	21 inches
Cutting Height	1.25 to 3.75 inches (8 positions)
Drive System	Rear-wheel self-propelled
Bag Capacity	2.0 bushels (approx. 2 gallons)
Deck Material	Powder-coated steel
Wheels	8-inch rear, 7-inch front
Starting System	Recoil pull-start
Fuel Tank Capacity	0.95 quarts (0.9 liters)
Weight	Approx. 65 lbs (unassembled)

Assembly Instructions

Unpack all parts from box. Verify contents against parts list.

Attach handle: Insert lower handle into deck brackets, secure with provided bolts and wing nuts.
Install grass bag: Attach bag support frame to rear deck, hook bag onto frame.
Attach wheels: Slide wheels onto axles, secure with retainer clips or washers.
Connect drive cable: Route cable from handle lever to transmission bracket as per diagram.
Add oil and fuel: Fill engine with SAE 30 oil (20 oz). Add unleaded gasoline (87 octane minimum).

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

Safety Precautions

Always follow safety guidelines to prevent injury.

Read manual thoroughly before operation.
Clear mowing area of sticks, stones, and debris.
Do not operate barefoot or in open-toed shoes; wear sturdy footwear and eye protection.
Never allow children or pets near mower during operation.
Stop engine and remove spark plug wire before performing maintenance.
Do not refuel while engine is hot or running.
Mow across slopes, not up and down, to prevent tipping.

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

Specifications

Model: 917.378941
Engine: Briggs & Stratton 190cc, 4-cycle
Cutting Width: 21 inches
Cutting Height Range: 1.25-3.75 inches
Deck Type: 3-in-1 (Mulch/Bag/Side-Discharge)
Drive: Self-propelled, rear-wheel
Wheels: 8-inch rear, 7-inch front
Bag Capacity: 2.0 bushels
Fuel Type: Unleaded gasoline (87 octane or higher)
Oil Type: SAE 30 (above 40°F) or 10W-30 (variable temps)
Weight: Approx. 65 lbs (unassembled)

Controls and Operation

Handle controls: Drive engagement lever, height adjustment lever, throttle control, recoil starter.

Starting: 1. Check oil and fuel levels. 2. Move throttle to FAST position. 3. Prime engine (if equipped). 4. Pull recoil starter firmly. Stopping: Release drive lever, move throttle to STOP, wait for blade to stop.

Self-propelled operation: Squeeze drive lever to handlebar to engage drive; release to stop. Adjust speed with throttle. For bagging: Install bag and close side discharge chute. For mulching: Install mulch plug. For side discharge: Remove bag and open chute.

Cutting Height Adjustment

Single-lever adjustment controls all four wheels simultaneously.

Stop engine and ensure blade is not rotating.
Pull adjustment lever toward wheel to unlock.
Move lever to desired height setting (1-8).
Release lever to lock into position.
Verify all wheels are at same height before mowing.

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

Maintenance Schedule

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 and cables
As needed	Clean underside of deck, inspect drive belt, tighten fasteners

WARNING! Always disconnect spark plug wire before performing any maintenance.

Engine Care

Briggs & Stratton 190cc engine requires regular maintenance.

Oil Change: Run engine briefly to warm oil. Drain via dipstick tube or drain plug. Refill with 20 oz SAE 30 (above 40°F) or 10W-30.
Air Filter: Remove cover, clean foam pre-cleaner (if equipped), replace paper element if dirty.
Spark Plug: Clean and gap to 0.030 inches; replace annually or if worn.
Fuel: Use fresh unleaded gasoline. Add fuel stabilizer for storage over 30 days.

CAUTION! Do not overfill oil; check level with dipstick on level surface.

Storage Guidelines

Proper storage extends mower life.

Drain fuel or add stabilizer and run engine 2 minutes to circulate.
Change oil and replace air filter at end of season.
Clean underside of deck thoroughly to prevent corrosion.
Remove spark plug, add 1 tablespoon oil to cylinder, pull starter slowly to coat.
Store in dry, covered area away from moisture and direct sunlight.

Tip: Inflate tires to recommended pressure before storage to prevent flat spots.

Warranty Information

Craftsman Model 917.378941 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 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 gas, clogged filter, bad spark plug	Check fuel level; use fresh gas; clean/replace air filter; check spark plug.
Engine runs poorly	Dirty air filter, old fuel, water in gas	Replace air filter; drain fuel tank and refill with fresh gas.
Uneven cutting	Dull blade, uneven tire pressure, deck clogged	Sharpen or replace blade; inflate tires evenly; clean deck underside.
Self-propelled not working	Drive cable loose/disconnected, drive belt worn	Adjust or reconnect drive cable; inspect and replace drive belt if needed.
Excessive vibration	Loose blade, bent blade, debris stuck	Tighten blade bolt; replace bent blade; remove debris from blade area.

Service: For technical support, call 1-888-331-4569 or visit www.craftsman.com.