Ariens 915251 Lawn Mower Manual

The Ariens 915251 is a high-performance walk-behind lawn mower designed for residential use. It features a durable steel deck, a powerful Briggs & Stratton engine, multiple cutting height adjustments, a rear-bagging grass collection system, and easy-start technology. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

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

Features at a Glance

Key components: Steel cutting deck, Briggs & Stratton engine, Rear grass bag, Height adjustment lever, Pull-start recoil, Mulching plug (optional), and Side discharge chute.

Feature	Description
Cutting Deck	21-inch steel deck for durable cutting performance
Engine	Briggs & Stratton 140cc engine with easy-start technology
Cutting Height	6-position adjustment lever (1.5" to 4")
Grass Collection	Rear-bagging system with 2.5-bushel capacity
Drive System	Self-propelled rear-wheel drive with variable speed control
Mulching Capability	Includes mulching plug for nutrient recycling
Safety Features	Blade control lever (deadman switch), protective deck design
Wheels	10-inch rear wheels, 8-inch front wheels for maneuverability
Weight	Approximately 65 lbs (unassembled)
Fuel Tank	0.5-gallon capacity

Assembly Instructions

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

Attach handle: Align lower handle with deck brackets, secure with provided bolts and wrench.
Install grass bag: Attach bag support frame to rear deck hooks, then hang collection bag.
Attach discharge chute: Secure side discharge chute to deck opening with wing nut.
Install mulching plug (optional): Insert plug into side discharge opening when mulching.
Add engine oil: Fill with SAE 30 detergent oil (18 oz) as per engine manual.
Add fuel: Use fresh unleaded gasoline (87 octane minimum).

WARNING! Do not add fuel or oil near open flames. Ensure all fasteners are tight before operation.

Safety Information

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

Clear mowing area: Remove stones, toys, and debris that could be thrown.
Check controls: Ensure blade control lever and drive control operate smoothly.
Start engine outdoors only: Never in enclosed spaces due to carbon monoxide risk.
Operate with care: Do not mow on steep slopes. Always walk, never run.
Keep hands and feet away: From rotating blades and discharge opening.
Stop engine: Before unclogging chute, adjusting height, or crossing gravel drives.

DANGER! Rotating blade can cause severe injury. Keep bystanders and pets away.

Specifications

Model: Ariens 915251
Cutting Width: 21 inches
Engine: Briggs & Stratton 140cc, 4-cycle, OHV
Starting System: Recoil pull-start
Cutting Heights: 1.5, 2, 2.5, 3, 3.5, 4 inches (6 positions)
Drive System: Self-propelled, rear-wheel drive, variable speed
Grass Bag Capacity: 2.5 bushels
Deck Material: Powder-coated steel
Warranty: 2-year limited warranty
Fuel Type: Unleaded gasoline (87 octane or higher)

Controls and Operation

Handle Controls: Blade control lever (must be held for blade rotation), Drive control lever (engage wheels), Speed control dial, Height adjustment lever.

Starting: 1. Push primer bulb 3 times (cold engine). 2. Set throttle to FAST. 3. Pull recoil starter firmly. Stopping: Release blade control lever; engine stops. Move throttle to STOP.

Self-Propelled Operation: Squeeze drive control lever to handle to engage wheels; adjust speed with dial. Mowing Tips: Overlap passes by 2-3 inches. Mow at steady pace. Empty bag when full.

Cutting Height Adjustment

Adjust all four wheels equally for level cut.

Stop engine and wait for blade to stop.
Pull height adjustment lever outward and move to desired position (1-6).
Release lever into notch; ensure all wheels are at same setting.
Test on small area; adjust if scalping occurs.

Tip: For first mow of season or very tall grass, use highest setting, then lower.

Maintenance Schedule

Regular maintenance ensures long life and safe operation.

Interval	Task
Before each use	Check oil level, inspect blade for damage, clear deck of debris
Every 25 hours	Change engine oil (SAE 30), check air filter, clean spark plug
Every season	Sharpen or replace blade, lubricate wheel axles and height adjuster
As needed	Replace grass bag if torn, check drive belt tension, clean underside of deck

Blade Sharpening: Remove spark plug wire. Tip mower on side (carburetor up). Use file to sharpen at original angle. Balance blade.

Storage Guidelines

Prepare mower for off-season storage to prevent fuel system issues.

Run engine to warm oil, then drain and refill with fresh oil.
Add fuel stabilizer to tank, run engine 5 minutes to circulate.
Either run engine until fuel tank is empty, or fill tank completely to prevent condensation.
Clean underside of deck thoroughly. Remove grass bag and store separately.
Store in dry, covered area. Protect from moisture and rodents.

CAUTION! Never store with fuel in tank indoors or near open flame.

Warranty Information

Ariens 915251 is covered by a 2-year limited warranty for residential use. Warranty covers defects in materials or workmanship. Not covered: normal wear, misuse, neglect, commercial use, or improper maintenance. Proof of purchase required. For warranty service, contact an authorized Ariens dealer or call 1-800-678-5443. Visit www.ariens.com for complete warranty terms.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No fuel, stale fuel, clogged air filter, spark plug	Check fuel level; use fresh gas. Clean/replace air filter. Check spark plug gap/connection.
Engine runs poorly	Dirty carburetor, old fuel, water in fuel	Drain fuel tank and carburetor. Refill with fresh gasoline. Consider carburetor cleaner.
Uneven cut	Dull blade, uneven tire pressure, deck clogged	Sharpen or balance blade. Check tire pressure (12 PSI). Clean underside of deck.
Self-propel not working	Drive belt loose or worn, control cable	Check drive belt tension and condition. Adjust or replace. Lubricate control cable.
Excessive vibration	Loose blade, bent blade, debris stuck	Stop engine. Tighten blade bolt (ft-lbs per manual). Replace bent blade. Remove debris.
Grass not discharging	Wet grass, deck clogged, high grass	Mow when grass is dry. Clean deck. Raise cutting height for very tall grass.

Service: For repairs beyond basic maintenance, contact authorized Ariens service center at 1-800-678-5443 or visit www.ariens.com.