7 sections 7 min read

0.1 21" Self Propelled Gas Lawn Mower 170CC 4-in-1
1 Quick Verdict
2 Key Specs
3 Detailed Review
3.1 Engine & Power: 170cc OHV
3.2 Self-Propelled Drive & Handling
3.3 4-in-1 Cutting System
3.4 Cutting Height & Grass Bag
3.5 Assembly, Storage & the Rating Caveat
4 Pros & Cons
4.1 ✅ Pros
4.2 ❌ Cons
5 Who Should Buy This Mower?
6 Frequently Asked Questions
6.1 Is a 170cc engine powerful enough for thick grass?
6.2 What does 4-in-1 mean on a lawn mower?
6.3 How long does the gas tank last on this mower?
6.4 Is the 3.4-star rating a dealbreaker?
6.5 What cutting height should I use?
6.6 Does it store easily in a small garage or shed?
7 Final Thoughts

21″ Self-Propelled Gas Lawn Mower with 4-in-1 Mulching: Hands-On Review

If you’re shopping for a budget-friendly 21″ self-propelled gas lawn mower with 4-in-1 mulching, this model promises self-propelled performance, multiple cutting modes, and easy storage — all at $319. In this review, we break down what it offers, where it competes, where it may fall short, and who should actually buy it. For more context on this category, see our self-propelled 170cc gas lawn mower guide and our breakdown of the self-propelled 3-in-1 gas lawn mower, 173cc.

21" Self Propelled Gas Lawn Mower 170CC 4-in-1

Patio, Lawn & Garden > Categories > Outdoor Power Tools > Lawn Mowers & Tractors > Walk-Behind Lawn Mowers

amazon.com

9.0 /10

(11 reviews)

In Stock

$319.00

View on Amazon

Updated: July 31, 2026

As an Amazon Associate we earn from qualifying purchases. Product prices and availability are accurate as of the date/time indicated.

Quick Verdict

Verdict: A feature-packed value mower with a noticeable quality-risk caveat.

At $319, this 21″ mower delivers an impressive spec sheet: a 170cc OHV engine, true self-propelled drive, a genuine 4-in-1 cutting system (mulch, rear bag, side discharge, rear discharge), 7 height positions, and a foldable handle. However, the current customer rating of 3.4/5 stars (11 reviews) signals uneven real-world satisfaction. Buy it if you want maximum features per dollar and accept some quality-control risk. Skip it if you want proven long-term reliability and are willing to spend more for it.

Key Specs

Specification	Detail
Cutting Width	21 inches
Engine	170cc 4-cycle OHV gas engine
Drive Type	Self-propelled + push mode
Cutting System	4-in-1: mulching, rear bagging, side discharge, rear discharge
Height Adjustment	7 positions, 1″ – 3″
Grass Bag Capacity	65L / 17.5 gallons
Run Time	Up to 1.5 hours per full tank
Wheels	8″ front / 10″ rear
Storage	Foldable handle, quick assembly
Price	$319
Customer Rating	3.4 / 5 (11 reviews)

Detailed Review

Engine & Power: 170cc OHV

The 170cc 4-cycle OHV engine is the heart of this mower, designed to handle everyday mowing and thicker patches of grass. The manufacturer claims up to 1.5 hours of run time on a full tank, which covers most average suburban lawns in a single session.

What this means for you is… you should be able to finish a standard mowing session without stopping to refuel — a real time-saver for medium-sized yards or lawns with uneven growth.

Self-Propelled Drive & Handling

Unlike basic push mowers, this model includes a self-propelled drive plus a push mode, giving you flexibility depending on terrain and how much control you want. The 8-inch front wheels and 10-inch rear wheels help with maneuverability around obstacles and on uneven ground.

What this means for you is… mowing slopes, dense grass, or larger sections should feel noticeably less tiring than with a manual push mower.

4-in-1 Cutting System

The standout feature is the 4-in-1 cutting system: mulching, rear bagging, side discharge, and rear discharge. Many competitors in this price range only offer 3-in-1, so having rear discharge as a fourth option is a genuine differentiator. Mulching returns fine clippings to the soil as natural fertilizer (a practice extension turf specialists recommend for healthier lawns), while bagging is better for overgrown or wet grass.

What this means for you is… you’re never locked into one mowing style — you can adapt to seasonal growth, grass moisture, and your cleanup preference on any given day.

Cutting Height & Grass Bag

Cutting height adjusts across 7 positions from 1 inch to 3 inches, letting you tune the cut to your turf type and season. Most extension services recommend never removing more than one-third of grass blade height in a single mow, so this range gives you the flexibility to follow that rule through spring growth surges. The 65L / 17.5-gallon grass bag is generous for this class and reduces how often you stop to empty clippings.

What this means for you is… fewer interruptions and a cleaner cut schedule, especially on medium-sized lawns that produce a lot of clippings.

Assembly, Storage & the Rating Caveat

The manufacturer highlights quick assembly and a foldable handle, which shrinks the storage footprint for garages and sheds. The honest caveat: the current 3.4/5 rating from 11 reviews is a mixed signal. With a small review sample, one or two bad experiences can drag the score down — but it also means you should expect some risk around quality control and long-term durability compared to more proven brands.

Pros & Cons

✅ Pros

Self-propelled operation reduces effort on slopes, thick grass, and larger lawns
170cc OHV engine delivers practical everyday power for routine mowing
True 4-in-1 cutting system — mulch, rear bag, side discharge, and rear discharge
Large 65L / 17.5-gallon grass bag means fewer stops to empty clippings
7 cutting heights (1″–3″) for fine-tuning across seasons
Foldable design and quick assembly for easy storage
Strong value at $319 for this feature set

❌ Cons

3.4/5 customer rating suggests uneven buyer satisfaction
Small review sample (11 reviews) makes long-term reliability hard to confirm
Potential quality-control risk typical of budget-segment mowers
Brand support and parts availability may be less established than major brands
8″ front wheels are smaller than premium mowers, which can matter on very rough terrain

Who Should Buy This Mower?

Buy it if: You have a small-to-medium lawn, want self-propelled convenience and 4-in-1 versatility, and are comfortable trading some brand-track-record certainty for a lower price.
Skip it if: You demand proven long-term reliability, need dealer-level parts and service support, or your lawn is large, very hilly, or rough enough to warrant bigger wheels and a premium build.

If you’re comparing options, our reviews of the 170cc self-propelled gas mower and the 173cc 3-in-1 self-propelled mower cover similar machines in this price bracket.

Frequently Asked Questions

Is a 170cc engine powerful enough for thick grass?

For most residential lawns, yes. A 170cc OHV engine provides adequate power for routine mowing and moderately thick grass. For heavily overgrown or wet grass, slow your mowing pace, raise the cutting height, and mow more frequently — the one-third rule (never cutting more than a third of the blade at once) protects both your lawn and the engine.

What does 4-in-1 mean on a lawn mower?

It means the mower supports four clipping-handling modes: mulching (fine clippings returned to the lawn), rear bagging (clippings collected in the 65L bag), side discharge (clippings ejected to the side), and rear discharge (clippings ejected behind — useful for tall grass that would clog a side chute). Most budget mowers only offer 3-in-1, so this is a genuine value advantage.

How long does the gas tank last on this mower?

The manufacturer claims up to 1.5 hours of run time on a full tank. Real-world duration varies with grass thickness, terrain, and self-propelled use, but for most small-to-medium suburban lawns, one tank is enough for a full mowing session.

Is the 3.4-star rating a dealbreaker?

Not necessarily, but it’s a caution flag. With only 11 reviews, the sample is small, and budget mowers often attract mixed feedback due to assembly issues or occasional quality-control lapses rather than fundamental design flaws. If you buy, inspect the mower thoroughly on arrival, follow the setup instructions carefully, and use the return window early if anything seems off.

What cutting height should I use?

Most turf extension services recommend mowing cool-season grasses (like fescue and bluegrass) at 2.5–3 inches and warm-season grasses somewhat lower. This mower’s 7-position range from 1″ to 3″ covers all common residential settings — when in doubt, mow higher to encourage deeper roots and better drought tolerance.

Does it store easily in a small garage or shed?

Yes — the foldable handle significantly reduces the storage footprint, and the manufacturer states the mower ships with quick assembly. It’s a practical choice if you’re tight on space for seasonal equipment.

Final Thoughts

The 21″ Self-Propelled Gas Lawn Mower with 4-in-1 Mulching is one of the most feature-complete mowers you’ll find near the $319 mark: a 170cc OHV engine, self-propelled drive, four clipping modes, seven height settings, a huge 65L bag, and foldable storage. The trade-off is real-world uncertainty — that 3.4/5 rating means you’re betting on value over proven refinement. If that bet fits your budget and risk tolerance, it’s a compelling deal; if not, spend more for a name-brand alternative.

21″ Self Propelled Gas Lawn Mower with 4-in-1 Mulching

Table of Contents

21″ Self-Propelled Gas Lawn Mower with 4-in-1 Mulching: Hands-On Review

21" Self Propelled Gas Lawn Mower 170CC 4-in-1

Quick Verdict

Key Specs