PowerSmart 21-Inch Gas Lawn Mower Review (2026): B8721S2

Powersmart 21-inch gas lawn mower review: the B8721S2 at a glance

Specifications are manufacturer rated, as published on the listing.

Who the PowerSmart B8721S2 is for

• Owners of small to medium lawns who want a straightforward gas mower: 21 inches of steel deck, a 140cc OHV engine and no batteries to plan around.
• People who switch discharge modes, since rear bagging, mulching and rear discharge cover collecting, recycling and spreading clippings.
• Yards with mixed grass and seasons, where the single-lever 6-position height adjustment from 1.5 to 3.9 inches adapts the cut.
• Buyers who push their mower: the title calls it a push mower, and the 10 inch rear wheels are sized for rolling over rough spots by hand.

The pick

PowerSmart B8721S2: a 140cc OHV gas push mower with a 21 inch steel deck, 3-in-1 rear bagging, mulching and rear discharge, 6-position single-lever height adjustment from 1.5 to 3.9 inches, and 10 inch rear wheels.

What 140cc and 21 inches mean in practice

The listing presents the 140cc OHV engine as dependable starting and power that mows through thick, tall or damp grass without bogging down, the maker’s claim. In plain terms, 140cc covers regular residential cutting; it is not a brush mower. The 21 inch steel deck is a common full-size walk-behind width, and the listing’s own point is that fewer passes finish larger lawns faster. Six height positions on one lever run 1.5 to 3.9 inches, a spread that covers short spring cuts and tall summer grass, and the spec table restates the same range as 3.81 to 9.91 cm. Listed dimensions are 32.9 in D by 16.5 in W by 22.6 in H, a compact footprint for shed storage.

The OHV in the engine spec stands for overhead valve, the common modern layout for small four-stroke engines, and the listing pairs it with a dependable-starting claim. The height range gets a second statement in the spec table as 3.81 to 9.91 cm, which is the same 1.5 to 3.9 inches in metric, so there is no contradiction there, just unit conversion. The listed 32.9 by 16.5 by 22.6 inch footprint is compact for a 21-inch mower: it stands in a shed corner or a garage wall slot without eating floor space, though you will still want to measure your storage spot against the 22.6-inch height with the handle folded.

What the B8721S2 does well

Standard full-size deck and engine pairing

Twenty-one inches and 140cc pair a full-size deck with a modest engine: wide enough to be efficient, small enough to maneuver. The steel deck and alloy steel construction are stated, which is what you want on a machine that meets rocks and roots.

The deck material is stated twice, as steel in the bullets and as alloy steel and metal in the spec table, which is consistent rather than contradictory. The 10-inch rear wheels are the largest rolling component the listing names, and on a push mower the rear wheels do the work over bumps and curb transitions. The 3-in-1 discharge setup means the mower ships ready for all three modes, with no extra chute or plug to buy, and the single-lever height control keeps the seasonal adjustment to one motion instead of four wheel-by-wheel changes.

Three discharge modes

Rear bagging, mulching and rear discharge switch with the 3-in-1 setup. Bag the spring flush, mulch the summer weeks, discharge the rough patches: one mower covers the options without extra parts to buy.

One-lever height control

Six positions from 1.5 to 3.9 inches on a single lever beats crawling around the deck adjusting four wheels. Seasonal changes and different grass types are a lever pull, not a project.

10 inch rear wheels

Larger rear wheels roll over bumps, roots and curb transitions easier than small ones. On uneven lawns this is a real comfort feature for a push mower.

Limitations to know before you buy

Push mower or rear-wheel drive?

The title calls it a push mower and the operation mode is listed as manual, but one bullet describes a rear-wheel-drive system with smooth propulsion. Those cannot both be true. This review follows the title and operation mode: a push mower, with the bullet’s drive claim treated as a listing contradiction worth confirming before you buy.

No weight stated

The spec table gives no item weight. On a push mower the weight is the workout, so its absence is the listing’s biggest gap: you cannot tell whether this is a light machine or a heavier one. The listing states no figure, so we say so.

No warranty term stated

No warranty length appears in the listing. With no term stated it earns no warranty points in our Acre Score, and there is no coverage promise to point to if something fails.

Front wheels not stated

The 10 inch rear wheels are listed; the front wheels are not. A push mower’s steering feel depends on all four, so the missing front figure is a gap.

140cc has limits

The engine is sized for maintained lawns, not for reclaiming overgrown ground. If your grass gets tall between cuts, the bogging the listing promises to avoid is still a risk.

Matching it to your property

• Small flat lawns: the full spec set works as a simple push mower; see how long an acre takes to size your session.
• Rough or uneven ground: 10 inch rear wheels are the stated answer for rolling over bumps; compare widths in walk-behind mower sizes.
• Yards with beds and trees: the mulch and rear discharge modes handle clippings where bagging around plantings is a nuisance.
• Storage: listed at 32.9 in D by 16.5 in W by 22.6 in H, it fits a shed or garage corner; see our gas mower picks for alternatives.

For storage, the 32.9-inch depth is the number to plan around: it is shorter than many 21-inch mowers, so it fits where a longer machine would not. On the lawn itself, the 21-inch deck and 6 cutting heights cover the standard residential routine, from a short 1.5-inch spring cut to a tall 3.9-inch summer cut that shades the soil. The rear discharge mode earns its keep on rough or overgrown patches where bagging would clog and mulching would mat.

FAQ: mowing large lots

What engine does the PowerSmart B8721S2 have?

A 140cc OHV gas engine, per the listing. Horsepower is not stated.

How wide does it cut?

21 inches on a steel deck, a common full-size walk-behind width.

Is it self-propelled?

The title says push mower and the operation mode is listed as manual, though one bullet mentions rear-wheel drive. Treat it as a push mower and confirm the drive claim with the seller before you buy.

Does it bag, mulch and discharge?

Yes. The 3-in-1 setup switches between rear bagging, mulching and rear discharge.

What is the cutting height range?

1.5 to 3.9 inches across 6 positions, adjusted with a single lever; the spec table restates it as 3.81 to 9.91 cm.

Is there a warranty?

No warranty term is stated in the listing.

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