Quick verdict
A 21-inch steel-deck gas push mower with a small 140cc class engine, pull start, a 2-in-1 deck for mulching or side discharge, six heights from 1.5 to 3.9 inches and 7-inch front and 10-inch rear wheels. It suits a flat small-to-medium lawn and a buyer who wants the simplest gas mower that will do the job. The caveat is that there is no bag, no drive, and the listing contradicts itself on engine size.
Strengths
- 21-inch steel deck covers a small lawn in few passes
- Simple pull-start engine with few parts to go wrong
- Six heights from 1.5 to 3.9 inches on dual levers
- 10-inch rear wheels roll over bumps and ruts
- Handles fold for storage
Weaknesses
- No rear bag, mulch or side discharge only
- Push only, no self-propelled drive
- Listing gives the engine as 140cc in the title and 144cc in the bullets
- Engine maker, weight and warranty not stated
The overall YardToolLab Score is out of 100. Section scores are out of 10.
Who this mower is for
Not every lawn needs a bag, a drive or a big engine. A flat quarter-acre lot that gets cut weekly is well served by the simplest gas mower on the market, and the AMERISUN 21-inch is about as simple as they come: a steel deck, a small pull-start engine, a mulch plug and a side chute. It is sold under the Amerisun name, the company behind the PowerSmart line, and it is aimed at the buyer who wants the fewest parts for the least money.
This review is based on the maker’s published specifications and on recurring owner feedback. We have not run this product ourselves.
What you get
The mower arrives with the handle folded and a manual. The deck is 21-inch steel with two modes, mulching and side discharge; there is no rear bag and none is offered in the listing. The engine is given as 140cc in the title and 144cc in the bullets, with a pull start. Cutting height runs from 1.5 to 3.9 inches in six positions on two levers. The wheels are 7 inches at the front and 10 inches at the rear. There is a start and stop control lever at the handle and safety shields over the discharge. The listing does not name the engine maker, state the weight, say whether oil is included or quote a warranty.
Engine and cutting
A 140cc class engine is the small end for a 21-inch deck. It is enough for a weekly cut on a lawn kept at a sensible height, and it will slow in thick spring growth, where the right response is to raise the deck, switch to side discharge and take narrower passes. Mulching works when the grass is dry and the cut is light; mulching long damp grass under any 21-inch deck leaves clumps, and this engine has less reserve than a 170cc unit to push through them. Pull start with no auto choke mentioned means following the starting routine in the manual, which owners of budget gas mowers say is reliable once learned.
Drive and handling
This is a push mower. Although it is often listed alongside self-propelled machines, the listing describes no drive system, so do not expect one. The 10-inch rear wheels are the handling feature: they roll over ruts and roots more easily than the 7-inch fronts and make the mower easier to tip back for a turn. On flat ground a 21-inch steel-deck gas mower is manageable to push; on a slope it is work, and a bigger lawn or a grade is the point at which to look at a self-propelled model instead.
Build and ergonomics
Steel decks last; they dent rather than crack and they take a repaint. The dual-lever height adjustment is slower than a single lever but simple and unlikely to loosen. The handle is described as ergonomic and folds for storage. Weight is not stated; a mower of this type typically lands in the 60 to 75 pound range. A recurring note from owners of budget gas mowers is to check the handle bolts and the wheel height detents after the first few cuts, since they can work loose with vibration.
Living with it
Gas mower upkeep applies in full: fill the crankcase before the first start if the mower ships dry, check the oil every few cuts, change it each season, replace the plug and air filter yearly, sharpen the blade twice a season and stabilize or drain the fuel for winter. Ethanol-free gas helps a small engine that sits. The warranty is not stated, so confirm the term and the support contact on the product page; for Amerisun and PowerSmart products that is normally phone or email.
Alternatives to Consider
The Craftsman M105 21-inch 140cc push mower is the mainstream equivalent, with a bag included and Lowe’s service behind it. The Murray 21-inch 140cc push mower is another basic gas option sold through Walmart. If you would rather drop the engine upkeep on a small flat lawn, the PowerSmart 80V 21-inch cordless push mower cuts the same width on a battery.
Verdict
Buy the AMERISUN 21-inch 140cc gas mower if you have a flat small-to-medium lawn, do not need a bag or a drive, and want the cheapest reliable way to keep it cut. Skip it if your lawn has slopes, you want to bag clippings, or you want a listing that is clear about what engine you are getting.
Full specifications
AMERISUN 21-Inch 140cc Gas Lawn Mower, 2-in-1 Mulching and Side Discharge, 6-Position Height Adjustment FAQs
No. The listing describes no drive system, so it is a push mower. The 10-inch rear wheels help it roll, but on a slope you are doing all the work.
The title says 140cc and the bullets say 144cc; the maker has not been consistent. Either way it is a small engine for a 21-inch deck, fine for weekly cuts and slower in thick growth.
Not with this mower. The 2-in-1 deck mulches or side discharges only, and no bag is listed as an accessory.
Amerisun is the company behind the PowerSmart outdoor power line, which is why this mower appears under both names. Support is by phone or email rather than through a dealer.
