PowerSmart
PowerSmart 21-Inch Self-Propelled Lawn Mower: B&S 140cc Engine Specs
The PowerSmart 21-inch self-propelled gas mower pairs a Briggs & Stratton 140cc engine with a wide steel deck and rear-wheel drive, making it a capable workhorse for medium to large yards. Its 3-in-1 discharge system and 6 cutting height positions offer real versatility, while rear-wheel drive gives it an edge on gentle slopes compared to front-wheel-drive competitors.
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Last updated: . Based on our analysis of 364 lawn mowers.
What Sets It Apart
Key specification highlights based on our analysis.
21.0-Inch Cutting Deck
Wide cutting path reduces passes (walk-behind avg: 18.0 in)
Steel Cutting Deck
Durable steel deck for long-term use
Briggs & Stratton Engine
Well-known engine brand with strong reputation and parts availability
Rear-Wheel Drive
Better traction on hills and slopes vs front-wheel drive
Why We Recommend It
- 01.
Wide 21-inch steel deck significantly cuts mowing time versus standard 18-inch decks on large lawns
- 02.
Briggs & Stratton 140cc engine is a well-known, reliable powerplant with readily available parts and service centers nationwide
- 03.
Rear-wheel drive provides noticeably better hill traction than front-wheel-drive models in this tier
- 04.
Six cutting heights adjustable from 1.5 to 3.9 inches via single lever makes height changes fast and tool-free
- 05.
3-in-1 system (bag, mulch, rear discharge) adapts to seasonal mowing jobs without extra attachments
Considerations
- 01.
At 69.9 lbs, this mower is heavier than many electric alternatives, which can make loading into a truck or navigating tight spaces more physically demanding
- 02.
Customer feedback is mixed on the self-propel system , some users report the drive not engaging reliably, which is a key feature to test early
- 03.
Gas engine requires ongoing maintenance (oil changes, air filter, spark plug, fuel stabilizer) that adds cost and time over the mower's life
Technical Specifications
| Feature | Specification |
|---|---|
| Mower Type | Self propelled |
| Power Source | Gas |
| Cutting Width | 21" |
| Deck Material | Steel |
| Blade Type | Rotary |
| Cutting Height | 1.5" – 3.9" |
| Height Positions | 6 |
| Engine | Briggs & Stratton 140cc |
| Drive | Rear wheel |
| Discharge | Mulch, Bag |
| Weight | 69.9 lbs |
Power & Performance
The Briggs & Stratton 140cc engine is the core of this mower's performance story. B&S engines are well-regarded for start-up reliability and consistent power delivery across a range of grass types, including thicker cool-season turf.
That said, real-world start-up performance can vary with age and fuel quality, so using fresh fuel and a fuel stabilizer in storage pays dividends.
Cutting System
The 21-inch rotary steel deck provides a cutting path that's meaningfully wider than the 18-inch industry average, reducing the number of passes needed on large lawns. Six cutting height positions span 1.5 to 3.9 inches and are controlled via a single lever, covering everything from a tight lawn-stripe cut to a taller, drought-tolerant height.
The 1.4-bushel rear bag is a reasonable size for medium lawns, and the mulching and rear-discharge options round out a flexible 3-in-1 deck setup.
Drive & Handling
Rear-wheel drive is a genuine advantage on this mower , it keeps traction under the heaviest part of the machine even when the bag is full, and handles mild grades better than front-wheel-drive models where the front wheels can lose grip on a slope. At 69.9 lbs the mower is solidly built, though that weight makes it less suited for tight gates or frequent transport.
The handle design follows a standard walk-behind layout and should suit most adult users.
Battery / Fuel
As a gas-powered mower, runtime is effectively unlimited as long as you have fuel , a clear advantage over battery models on large properties. The B&S 140cc engine runs on standard 87-octane unleaded fuel.
Maintenance requirements include seasonal oil changes, annual spark plug and air filter replacement, and draining or stabilizing fuel before winter storage. Users who stay on top of these tasks consistently report better start-up performance and longer engine life.
Who Is This Mower For?
Ideal For
- ✓ Homeowners with large yards (1/2 acre or more) who need a wide 21-inch deck and self-propelled drive to reduce fatigue over long mowing sessions
- ✓ Buyers who prefer the proven reliability and first-pull start performance of a Briggs & Stratton engine over battery-powered alternatives
- ✓ Yards with mild slopes or uneven terrain where rear-wheel drive provides meaningful traction advantages over front-wheel-drive models
- ✓ Users who want versatility across seasons , mulching clippings in summer, bagging leaves in fall, or using rear discharge for thick growth
Not Ideal For
- ✕ Eco-conscious users or those in areas with strict emissions rules , this gas engine produces emissions and requires petroleum fuel
- ✕ Homeowners with very small yards under 1/4 acre where a corded or battery electric mower would be lighter, quieter, and entry-level to run
- ✕ Users who want truly low-maintenance mowing , gas engine upkeep (oil, filter, spark plug, fuel system) is a recurring commitment
Customer feedback consistently describes assembly as straightforward, with most users completing setup in under 30 minutes. The majority of the mower arrives pre-assembled, with handle attachment and basic hardware connection being the primary steps.
Add fresh oil and fresh fuel before the first start , the engine ships dry and pre-start lubrication protects the B&S engine from day one
Test the self-propel drive immediately after assembly; if it doesn't engage smoothly, adjust the drive cable tension before taking the mower out on the full lawn
Warranty terms for this PowerSmart model should be confirmed directly with the manufacturer or retailer at time of purchase, as coverage periods can vary by sales channel. Briggs & Stratton engines typically carry their own separate warranty, and the widespread B&S service network means engine support is accessible in most regions.
FAQ
How does the self-propelled drive work on this PowerSmart mower?
This mower uses rear-wheel drive, engaged via a bail handle or drive lever on the handlebar. Rear-wheel drive pushes from the back wheels, which gives better traction on slopes and when the grass catcher is full compared to front-wheel-drive designs.
Some customers have reported the self-propel feature not engaging reliably, so it's worth testing the drive cable tension after assembly.
What size yard is the PowerSmart 21-inch gas mower best suited for?
PowerSmart rates this mower for large yards, and the 21-inch deck supports that , a wider cut than the 18-inch average means fewer passes and less total mowing time on properties of 1/2 acre or more. Smaller yards under 1/4 acre could use this mower but won't get the same efficiency benefit, and a lighter electric model might be more practical.
Does the Briggs & Stratton engine start easily?
B&S engines have a strong reputation for start-up reliability, and many users report first-pull starts. However, some customers have experienced difficulty starting, which is often linked to old or ethanol-blended fuel, a dirty air filter, or a worn spark plug.
Using fresh 87-octane fuel and following the seasonal maintenance schedule keeps start-up performance consistent.
Can this mower handle hills and slopes?
The rear-wheel drive system gives this mower a genuine advantage on gentle to moderate slopes compared to front-wheel-drive competitors, because traction stays under the heaviest part of the machine. It's rated as a good fit for hilly terrain.
For very steep grades, a high-wheel or all-wheel-drive mower would be more appropriate.
How do I switch between mulching, bagging, and rear discharge?
This is a 3-in-1 deck, meaning you can mulch clippings back into the lawn, collect them in the 1.4-bushel rear bag, or use rear discharge for heavy or tall grass. Switching between modes typically involves attaching or removing the grass bag and inserting or removing a mulch plug , no tools required.
The rear-discharge option is particularly useful when tackling overgrown or wet grass where mulching would clump.
How heavy is this mower and is it easy to maneuver?
The PowerSmart 21-inch mower weighs 69.9 lbs, which is on the heavier end for a walk-behind. The self-propelled rear-wheel drive offsets most of that weight during mowing, but you'll feel it when lifting over a threshold, loading into a vehicle, or navigating very tight spaces.
For users with standard open lawns, the drive system makes the weight a non-issue during actual mowing sessions.
Bottom Line
The PowerSmart 21-inch gas self-propelled mower is a solid pick for homeowners with large, flat-to-moderately-hilly yards who want the proven reliability of a Briggs & Stratton engine and the versatility of a 3-in-1 deck at an accessible tier. The wider steel deck, rear-wheel drive, and 6 cutting heights are genuine strengths, though buyers should verify the self-propel system early and be comfortable with routine gas engine maintenance.
Best for large-yard homeowners wanting a gas-powered, self-propelled B&S mower with versatile 3-in-1 discharge and solid hill traction.
Consider alternatives if you want zero-emissions mowing, prefer battery-electric convenience, or need a lighter mower for frequent transport or storage in tight spaces.
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