The Murray 405028X51 is a 21-inch, 3-in-1 push lawn mower featuring a 159cc Briggs & Stratton engine, rear bagging, side discharge, and mulching capabilities. It includes a single-lever height adjustment system (6 positions: 1.5-3.75 inches), durable steel deck, easy-start system, and a 2.1 bushel grass bag. Below are key sections for safety, features, assembly, operation, maintenance, troubleshooting, and specifications.
Key components: 159cc Briggs & Stratton engine, 21-inch steel cutting deck, 3-in-1 functionality (Bag, Mulch, Side Discharge), single-lever height adjustment, 2.1 bushel rear bag, and easy-start system.
| Feature | Description |
|---|---|
| Engine | 159cc Briggs & Stratton 450E Series, OHV |
| Cutting Width | 21 inches |
| Cutting Height | 6 positions (1.5 - 3.75 inches) |
| Deck Material | Durable steel |
| Discharge Options | Rear bag, side discharge, mulching |
| Grass Bag Capacity | 2.1 bushels |
| Start Type | Recoil start |
| Wheels | 8-inch rear, 7-inch front |
| Weight | Approximately 65 lbs |
| Warranty | 2-year limited |
Unpack and inspect all parts. Assembly requires basic tools (included).
WARNING! Wear gloves during assembly. Ensure all bolts are tightened securely. Do not attempt to start engine before assembly is complete.
Before first use, complete these essential steps.
CAUTION! Always check oil level before starting. Never run engine without proper oil level. Fuel and oil are not included.
Main controls: Engine control lever (combines choke/throttle), recoil starter, height adjustment lever, and bag handle.
Starting Procedure:
Stopping: Move engine control lever to STOP position. Always wait for all moving parts to stop completely before leaving mower unattended.
Configure mower for desired cutting method:
Height Adjustment: Use single lever to raise/lower deck. Adjust based on grass type and season.
Tip: For best results, never cut more than 1/3 of grass height at one time. Keep blade sharp for clean cuts.
| Maintenance Task | Frequency | Procedure |
|---|---|---|
| Check Oil Level | Before each use | Ensure oil is at full mark on dipstick |
| Check Air Filter | Every 25 hours | Clean or replace foam filter |
| Sharpen Blade | Every season or 25 hours | Remove blade, sharpen at 30° angle, balance |
| Change Oil | First 5 hours, then every 50 hours | Drain warm oil, refill with SAE 30 |
| Spark Plug | Every 100 hours | Clean and gap to 0.030 inches |
| Clean Underside | After each use | Scrape debris from deck |
WARNING! Always disconnect spark plug wire before performing any maintenance. Allow engine to cool completely.
Proper storage extends mower life.
CAUTION! Never store mower with fuel in tank in enclosed area. Gasoline vapors are explosive.
READ BEFORE OPERATING:
DANGER! Rotating blade can cause serious injury. Always disconnect spark plug before inspecting or servicing blade.
Murray 405028X51 includes a 2-year limited warranty covering defects in materials and workmanship. Warranty does not cover normal wear, misuse, or lack of maintenance.
Customer Support: For parts, service, or warranty claims:
Always have model number (405028X51) and serial number ready when contacting support.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Engine won't start | No fuel, old gas, clogged filter | Add fresh fuel, clean air filter, check spark plug |
| Engine runs poorly | Dirty air filter, bad gas | Clean/replace air filter, drain old fuel |
| Uneven cutting | Dull blade, uneven tire pressure | Sharpen blade, inflate tires to 20 PSI |
| Vibration | Loose blade, bent blade | Tighten blade bolt, replace bent blade |
| Bag not filling | Wet grass, clogged chute | Mow when grass is dry, clean discharge chute |
| Wheels not turning | Debris in wheel hubs | Clean wheel axles, lubricate if necessary |
Safety First: Always disconnect spark plug before troubleshooting mechanical issues.
Service: For complex repairs, contact authorized Murray service center.