2-Stroke vs 4-Stroke Outboards: Which Should You Buy?

If you’ve been researching outboard motors for more than five minutes, you’ve likely come across older listings, forum threads, or second-hand motors described as “2-stroke.” It’s worth understanding what that actually means before you buy — even though, as you’ll see below, it’s largely a historical comparison at this point rather than a live choice between two current options.

The Core Difference

A 2-stroke engine completes its power cycle in a single crankshaft revolution, mixing oil directly with the fuel to lubricate internal components as it burns. A 4-stroke engine — the design used in every motor we sell — separates the oil and fuel systems entirely, running its own dedicated oil sump much like a car engine. That single design difference is what drives almost every practical distinction between the two.

Fuel Efficiency and Running Costs

Because a 2-stroke burns oil along with its fuel, a portion of every tank is lost to that combustion rather than converted into propulsion. A 4-stroke’s separate oil system means fuel is burned more completely and efficiently, which typically translates to meaningfully better fuel economy over a season of regular use — a real factor if you’re putting significant hours on the water.

Noise and Smoothness

Older 2-stroke outboards are known for a distinctive higher-pitched, buzzier note, particularly at idle and low speed. Four-stroke motors run noticeably quieter and smoother, closer to the character of a car engine ticking over — which matters more than it might sound if you’re fishing early mornings or spending long days on the water with passengers aboard.

Emissions

Because unburnt oil and fuel exit a 2-stroke engine as part of normal operation, they produce meaningfully higher emissions than an equivalent 4-stroke. This is also the main reason 2-stroke outboards have been progressively phased out of new production across the industry — modern emissions standards in most markets, Australia included, are difficult for a traditional 2-stroke design to meet.

Weight

Historically, 2-strokes have held a genuine weight advantage — fewer internal components and no separate oil system make for a lighter motor at a given horsepower. Four-stroke engineering has closed much of that gap over the last two decades, but it’s still a factor worth knowing about if you’re mounting a motor near your boat’s maximum rated weight or transom capacity.

Why We Only Stock Four-Stroke Motors

At Wave Engines, every motor we sell — across Yamaha, Mercury, Honda, Suzuki and Tohatsu — is a genuine, new four-stroke engine, sourced through authorised supply channels. This isn’t really a stocking decision so much as a reflection of where the whole industry has landed: new 2-stroke outboards are now rare across all major manufacturers, and four-stroke has become the standard for anyone buying new rather than sourcing an older second-hand motor.

If you’re comparing a new 4-stroke against a used 2-stroke on price alone, it’s worth weighing the fuel savings, lower maintenance, and manufacturer warranty of a new motor against the upfront cost difference — over several seasons of use, the gap often narrows more than buyers expect.

Choosing the Right Four-Stroke for Your Boat

Once you’ve settled on a four-stroke — which, in practice, means any new motor purchased today — the decision comes down to horsepower, shaft length, and control type for your specific boat. Our HP Finder tool walks through exactly that, or you can browse the full range by power bracket directly.

Have questions about switching from an older 2-stroke to a new four-stroke motor, or want help matching a model to your boat? Contact our team at 85 Tope Street, South Melbourne, or check our FAQ page for more on servicing, freight, and warranty.