Toro Model 20378 Manual

The Toro Model 20378 is a high-performance walk-behind lawn mower designed for residential use. It features a powerful engine, adjustable cutting heights, a durable steel deck, a rear bagging system, and ergonomic controls for comfortable operation. This manual covers safety instructions, assembly, operation, maintenance, troubleshooting, and specifications to ensure proper use and longevity of your mower.

Features at a Glance

Key components: Steel cutting deck, Briggs & Stratton engine, rear collection bag, height adjustment lever, ergonomic handle, and safety key.

Feature	Description
Engine	Briggs & Stratton 140cc OHV engine for reliable power
Cutting Width	21-inch steel cutting deck
Cutting Height	Adjustable from 1.5 to 4 inches in 0.5-inch increments
Drive System	Self-propelled rear-wheel drive with variable speed control
Collection System	Rear bag with 2.5-bushel capacity
Handle	Ergonomic, foldable handle with cushioned grips
Safety Features	Safety key, blade brake clutch system, and operator presence control
Mulching Capability	Optional mulching kit available (sold separately)
Wheels	8-inch rear wheels, 7-inch front wheels
Weight	Approximately 65 lbs

Assembly Instructions

Unpack all parts and inspect for damage. Assemble on a flat, clear surface.

1. Attach the handle: Align handle brackets with deck mounts and secure with provided bolts and wrenches.
2. Install the collection bag: Attach bag support frame to rear discharge chute and hook bag onto frame.
3. Connect the drive cable: Route cable through handle and attach to engine linkage as shown in diagram.
4. Install the safety key: Insert key into ignition slot on handle.
5. Add oil and fuel: Fill engine with SAE 30 oil (check dipstick) and unleaded gasoline (87 octane minimum).

WARNING! Do not attempt to start the engine before completing assembly and adding oil. Keep hands and feet clear of moving parts during assembly.

Safety Information

Read all safety instructions before operating. Always wear appropriate protective equipment.

1. Clear mowing area of stones, toys, and other objects that could be thrown by the blade.
2. Never operate without the grass bag, discharge chute, or mulch plug properly installed.
3. Do not mow on steep slopes (over 15 degrees) or wet grass.
4. Keep bystanders, especially children and pets, at least 50 feet away during operation.
5. Always turn off engine and remove safety key before unclogging, adjusting, or performing maintenance.

CAUTION! The blade is sharp and can cause serious injury. Never place hands or feet under the deck while engine is running.

Specifications

• Model: Toro 20378
• Engine: Briggs & Stratton 140cc OHV, 4-cycle
• Fuel Type: Unleaded gasoline (87 octane minimum)
• Oil Type: SAE 30 detergent oil (20 oz capacity)
• Cutting Width: 21 inches
• Cutting Heights: 1.5, 2, 2.5, 3, 3.5, 4 inches
• Bag Capacity: 2.5 bushels
• Drive System: Self-propelled rear-wheel drive, variable speed (0-3.5 mph)
• Warranty: 2-year limited residential warranty
• Dimensions (LxWxH): 45 x 22 x 40 inches (assembled)

Controls and Operation

Handle Controls: Throttle lever, drive control lever, height adjustment lever, safety key ignition.

Operation: Insert safety key, set throttle to FAST, pull recoil starter. Engage drive control to move forward; release to stop movement. Adjust speed with drive control lever pressure.

Cutting: Always mow at full throttle for best cut. Overlap passes by 2-3 inches for even cutting. Empty bag when full to maintain performance.

Starting and Stopping

Starting: Ensure area is clear. Insert safety key. Set throttle to FAST. Pull recoil starter firmly. For cold starts, use choke if equipped.

1. Check oil and fuel levels before starting.
2. Prime engine (3-5 presses) if temperature is below 50°F.
3. Engage blade by pulling blade control lever toward handle.
4. To stop: Release blade control, set throttle to STOP, remove safety key.

Tip: If engine does not start, check safety key, spark plug, and fuel. Do not crank for more than 10 seconds at a time.

Cutting Height Adjustment

Adjust all four wheels evenly for level cut.

1. Stop engine and remove safety key.
2. Locate height adjustment lever near each wheel.
3. Move lever to desired setting (1-6 corresponding to 1.5-4 inches).
4. Ensure all levers are set to same position.
5. Test on a small area before full mowing.

WARNING! Never adjust cutting height while engine is running. Always mow at recommended height for grass type (typically 2.5-3 inches for most lawns).

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 oil, clean or replace air filter, check spark plug
Every 50 hours	Sharpen or replace blade, check drive belt tension
Season end	Drain fuel or add stabilizer, clean entire mower, lubricate moving parts
Season start	Change oil, install fresh fuel, test operation

CAUTION! Always disconnect spark plug wire before performing any maintenance to prevent accidental starting.

Storage Guidelines

Proper storage prevents fuel system issues and corrosion.

1. Drain fuel tank or add fuel stabilizer and run engine for 5 minutes.
2. Change oil at end of season.
3. Clean underside of deck thoroughly to remove grass buildup.
4. Store in dry, covered area away from moisture and direct sunlight.
5. Remove battery (if electric start model) and store separately.

Tip: Consider professional servicing before long-term storage if mower has been heavily used.

Warranty Information

Toro Model 20378 comes with a 2-year limited warranty for residential use. Warranty covers defects in materials and workmanship when used as directed. Not covered: commercial use, neglect, improper maintenance, unauthorized repairs, normal wear items (blades, belts, tires). For warranty service, contact authorized Toro dealer with proof of purchase. For support, visit www.toro.com or call 1-800-348-2424.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Empty fuel tank, old fuel, dirty spark plug, safety key not inserted	Add fresh fuel, replace spark plug, ensure safety key is fully inserted
Engine runs poorly	Dirty air filter, clogged fuel line, old oil	Clean/replace air filter, drain fuel tank and refill, change oil
Uneven cutting	Dull blade, uneven tire pressure, incorrect cutting height	Sharpen or replace blade, inflate tires to 15 PSI, adjust height evenly
Mower doesn't drive	Drive cable disconnected, drive belt worn, control lever not engaged	Reconnect drive cable, replace drive belt, fully engage drive control
Excessive vibration	Loose blade, bent blade, debris in blade area	Tighten blade bolt (torque to 45 ft-lbs), replace bent blade, clean deck

Service: For repairs not covered in manual, contact authorized Toro dealer. Do not attempt major engine repairs yourself.

Support: 1-800-348-2424; www.toro.com