Pick a Rotax engine and you are picking the heart of your airplane. These small Austrian powerplants fly everything from featherweight ultralights to fast cross-country machines. The four names that come up most often are the 912, the 914, the 915, and the 916.
From across the hangar, they look a lot alike. Read the spec sheets side by side, and the family resemblance starts to fade fast.
The Rotax 916 vs 915 vs 914 vs 912 question is really a question about your mission. How high do you fly? How heavy is your airframe? How much do you want to spend at the fuel pump and again at overhaul time? Each engine answers those questions in its own way, and there is no single "best" pick for every pilot.
Two of these engines make almost the same continuous power in cruise. Yet one of them costs thousands more and is built to run far longer. The reason hides inside the crankcase.
Key Takeaways
The 912 is the light, simple, affordable workhorse. The 914 adds a turbo for steady power up high. The 915 iS brings modern fuel injection and 141 horsepower. The 916 iS sits on top with 160 horsepower and the longest rated service life of the four. The right choice depends on how high and how heavy you fly, and how much you want to spend up front and over time.
| Engine | Power (takeoff) | Aspiration | Fuel system | Approx. weight | TBO | Best for |
| Rotax 912 | 80 to 100 hp | Naturally aspirated | Carb or fuel injection | Lightest (~125 to 145 lb) | 2,000 hrs | Trainers, light sport, budget builds |
| Rotax 914 | 115 hp | Turbocharged | Carbureted | ~165 lb | 2,000 hrs | Altitude flying on a budget |
| Rotax 915 iS | 141 hp | Turbo + intercooler | Fuel injection | ~185 lb | 1,200 hrs | Modern cross-country builds |
| Rotax 916 iS | 160 hp | Turbo + intercooler | Fuel injection | ~185 to 190 lb | 2,000 hrs | Maximum power and longevity |
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Meet the Rotax Family: A Quick Background
Rotax has been building aircraft engines since the 1970s. The company is based in Austria and is owned by BRP, the same group behind Ski-Doo snowmobiles and Sea-Doo watercraft. Over the years, Rotax aircraft engines have racked up tens of millions of flight hours around the world. They power a huge share of the light sport and experimental fleet.
The story really starts with the Rotax 912 series. The first 912 arrived in the late 1980s as a small, light, four-cylinder engine. It did something clever for its size. It used air-cooled cylinders paired with liquid-cooled heads, and it spun fast while a gearbox slowed the propeller down to a useful speed. That mix gave it a strong power-to-weight ratio and a smooth, reliable character that pilots loved.
From there, the family grew step by step:
- Rotax 912 (1989 onward): the naturally aspirated original, offered in 80 hp and later 100 hp forms.
- Rotax 914 (1996): a turbocharged version of the 912 that holds power at higher altitudes.
- Rotax 915 iS (announced 2015, available around 2017): a more powerful, fuel-injected design built for a bigger class of aircraft.
- Rotax 916 iS (introduced 2023): the newest and strongest of the bunch, with internals reworked for more power and a long service life.
Each new engine built on the one before it. None of them fully replaced the others. That is why all four are still sold and flown today.
Good to Know: You can often spot a Rotax model by the color of its cylinder covers. The older carbureted 912 wears black, the 912 iS is green, the 914 shows red, the 915 iS runs blue, and the 916 iS comes in grey. It is a handy shortcut on a crowded ramp.
What Sets These Four Engines Apart
Before lining them up number against number, it helps to understand the handful of features that actually separate them. Most of the differences come down to six things.
Power and How It Is Made
Power is the headline, so start there. The 912 makes between 80 and 100 horsepower, depending on the version. The 914 steps up to 115 horsepower. The 915 iS jumps to 141 horsepower for takeoff. The 916 iS tops the chart at 160 horsepower for takeoff.
Here is the part many pilots miss. Takeoff power and cruise power are not the same number. Takeoff power is a short burst, usually allowed for about five minutes. Continuous power, the number you use for most of the flight, is lower. The 915 iS holds about 135 horsepower continuous. The 916 iS holds about 137 horsepower continuous. So at cruise, those two are almost twins, even though their takeoff figures are 19 horsepower apart.
Fun Fact: The 916 iS earned the nickname "the impossible engine" because Rotax squeezed more power and a longer service life out of nearly the same package without piling on much extra weight.
Carburetors vs Fuel Injection
How each engine feeds itself is a big dividing line. The classic 912 (in its UL and ULS forms) and the 914 both use carburetors. Carburetors are simple, proven, and easy to work on. They also need balancing now and then, and they run a fixed mixture that is not always ideal.
The 912 iS, the 915 iS, and the 916 iS use electronic fuel injection instead. A small computer meters fuel to each cylinder and adjusts the mixture on the fly. That brings better efficiency, easier starting, and an "economy" mode that leans things out during cruise to save fuel. The trade is a more complex system with sensors, pumps, and a return fuel line that the airframe has to support.
Weight and Power-to-Weight
Adding power usually means adding weight, and these engines follow that rule. The 912 family is the lightest, which is exactly why it dominates the very weight-sensitive light sport class. The 914 adds the turbo, plumbing, and related parts, so it weighs more. The 915 iS and 916 iS are heavier again, landing in the same general neighborhood as each other.
The 916 iS is the impressive one here. It delivers a big bump in power over the 915 iS while adding only a small amount of weight. For a builder watching every pound, that matters.
Pro Tip: When you compare published weights, check what each figure includes. Some numbers are bare engine weight. Others add the gearbox, exhaust, airbox, and mounts. Comparing a bare weight to a fully dressed weight makes one engine look lighter than it really is.
Altitude Performance
This is where the turbo earns its keep. A naturally aspirated engine like the 912 loses power as you climb, because the air thins out. The turbocharged 914 fights that loss and holds its power much higher than the 912 can.
The 915 iS and 916 iS take it further. Both can hold full takeoff power up to about 15,000 feet and keep climbing to a service ceiling near 23,000 feet. For mountain flying, hot-and-high airports, or long cross-country trips at altitude, that ability is a game changer.
Time Between Overhaul
Time between overhaul, or time between overhaul (TBO), tells you how many hours the maker expects between major rebuilds. It feeds straight into your cost per flight hour. Here the four engines split in an interesting way.
The 912 and the 914 carry a well-established 2,000-hour TBO. The 916 iS launched with a 2,000-hour TBO right out of the gate, which is unusual for a brand-new design. The 915 iS, by contrast, has carried a shorter TBO of around 1,200 hours. Rotax built the 916 with internal changes that support the longer life, and those changes are part of why the 916 reads as a near-new engine inside rather than a tweaked 915.
Heads Up: TBO is a manufacturer recommendation, and the exact figure can change over time or vary by region and certification. Always confirm the current TBO for your specific engine model and serial range against the latest Rotax documentation before you budget for overhaul.
Fuel Burn and Running Costs
Fuel use roughly tracks power and fuel system. The 912 sips the least, which is part of its budget-friendly charm. The 914 burns a bit more for its extra power. The fuel-injected 915 iS and 916 iS burn more at full song than the smaller engines, but their economy mode makes them efficient at cruise. Pilots commonly report cruise burns in the range of 6 to 8 gallons per hour on the bigger two, which is reasonable for that power level.
Rotax 916 vs 915 vs 914 vs 912: A Point-by-Point Breakdown
Now line them up directly. The table below puts the headline numbers side by side, and the points after it explain what those numbers mean in real flying.
| Spec | 912 ULS / iS | 914 UL | 915 iS | 916 iS |
| Takeoff power | ~100 hp | 115 hp | 141 hp | 160 hp |
| Max continuous | ~95 hp | ~100 hp | 135 hp | 137 hp |
| Aspiration | Naturally aspirated | Turbocharged | Turbo + intercooler | Turbo + larger intercooler |
| Fuel delivery | Carb (ULS) / EFI (iS) | Carburetors | Electronic fuel injection | Electronic fuel injection |
| Displacement | 1,352 cc | 1,211 cc | 1,352 cc | 1,352 cc |
| Full power to | Sea level | Higher altitude | ~15,000 ft | ~15,000 ft |
| Service ceiling | Lower | Higher | ~23,000 ft | ~23,000 ft |
| Approx. weight | Lightest | ~165 lb | ~185 lb | ~185 to 190 lb |
| TBO | 2,000 hrs | 2,000 hrs | ~1,200 hrs | 2,000 hrs |
Here is how those rows translate into decisions:
- Raw power climbs with each model. From 100 hp on the 912, to 115 hp on the 914, to 141 hp on the 915 iS, to 160 hp on the 916 iS. More power means stronger climb and faster cruise, at the cost of weight and money.
- Only one of the four is naturally aspirated. The 912 has no turbo. The 914, 915, and 916 all use forced induction, which is what lets them hold power as the air thins.
- Fuel injection separates old from new. The carbureted 912 and 914 are simple to service. The fuel-injected 912 iS, 915, and 916 add a computer-managed system with better economy and easier starts.
- Displacement is not the whole story. The 914 actually has the smallest displacement of the group, yet it makes more power than the larger 912 thanks to its turbo. Cubic centimeters alone do not predict horsepower.
- Altitude is the turbo engines' home turf. The 915 and 916 hold full takeoff power to roughly 15,000 feet and reach for a ceiling near 23,000 feet. The 914 also performs well up high. The 912 fades as it climbs.
- Weight rises with capability. The 912 is the lightweight champ. The 915 and 916 are the heaviest, sitting close to each other, with the 916 adding only a little over the 915 for a real jump in output.
- TBO is a quiet but huge factor. The 912, 914, and 916 share a 2,000-hour rating, while the 915 has carried a shorter one. Over the life of an engine, that gap changes your true cost per hour.
- Cruise power can be a near tie. The 915 and 916 make almost the same continuous power, so they feel similar once you are settled in cruise. The 916's edge shows up most in takeoff, climb, and high-density-altitude days.
- Fuel system drives running cost as much as fuel burn. Carbureted engines are cheaper to maintain. Fuel-injected engines can save fuel and add convenience, but they ask for more careful upkeep.
- The "right" engine is mission-shaped. A short-field trainer, a mountain tourer, and a fast glass-cockpit cross-country build will each point at a different model from this list.
If you want to see how these turbocharged figures sit against piston rivals from other makers, the turbocharged Rotax engine lineup is often weighed against a Lycoming IO-360 and against a Titan 340 by builders shopping the 150-to-180 horsepower range.
Shopping for the engine itself? Flying411 lists new, used, and overhauled Rotax engines from sellers and shops, so you can compare what is actually on the market right now.
Which Rotax Engine Is Right for You
Numbers are useful, but most pilots want a recommendation they can act on. Here is a plain-language guide to who each engine suits best.
Best for First-Time Buyers and Light Builds: the 912
If you are building or buying a two-seat trainer, a classic light sport aircraft, or a simple weekend flyer, the 912 is the natural starting point. It is light, affordable, well understood, and supported almost everywhere. Parts are easy to find. Mechanics know it inside and out. For a low-and-slow mission near sea level, it does everything most pilots need and nothing they do not.
As a light sport aircraft engine, the 912 is the benchmark that other powerplants get measured against. That popularity is its own kind of insurance, because the knowledge base and parts network around it are deep.
Keep in Mind: The 912 comes in both carbureted (ULS) and fuel-injected (iS) forms. The carbureted version is simpler and cheaper to maintain. The injected version sips less fuel and starts more easily. Match the variant to how hands-on you want to be.
Best for Altitude on a Budget: the 914
The 914 is the sweet spot for pilots who need to hold power up high but do not want to step all the way up to the newest engines. Its turbo keeps it strong at altitude, and it does so with familiar carburetors that are straightforward to service. For mountain flyers, gyroplanes, and aircraft that operate from high-elevation strips, the 914 has earned a loyal following over many years.
It is older technology than the 915 and 916, and it lacks fuel injection. For a lot of missions, that simplicity is a feature, not a flaw.
Best All-Around Modern Performer: the 915 iS
The 915 iS was a real leap when it arrived. It brought fuel injection, an intercooled turbo, and 141 horsepower to airframes that used to top out at 115. It holds full power to 15,000 feet and climbs toward a 23,000-foot ceiling. For a modern cross-country machine with a glass cockpit, it is a strong, proven choice.
The main thing to weigh is its shorter TBO compared to the others. If you fly a lot of hours, factor that overhaul timing into your cost planning. The closer 914 vs 915 comparison is worth a look if you are torn between the turbo carbureted engine and this fuel-injected one.
Best for Maximum Power and Longevity: the 916 iS
The Rotax 916 iS is the flagship. It delivers the most takeoff power of the family at 160 horsepower, holds strong at altitude, and carries a 2,000-hour TBO from launch. Rotax reworked its internals to handle the extra heat and stress, which is why it reads as nearly a new engine despite sharing a family tree with the 915.
It is the most expensive of the four to buy, and it asks for a specific fully synthetic oil that the older engines do not use. For a builder who wants the best climb, the best high-and-hot performance, and the longest rated life, the 916 iS is hard to top. Some owners find that the longer TBO and better cruise efficiency soften the higher purchase price over the life of the engine.
Why It Matters: The 916's 2,000-hour TBO is not just a bigger number. Spread the cost of an overhaul across more hours, and your real cost per flight hour can drop, even though the engine costs more on day one. For high-time pilots, that math can flip the whole decision.
How They Compare to Other Engines
The Rotax four are not the only game in town, and smart buyers cross-shop. If you are weighing a Rotax against engines from other makers, a few head-to-head matchups help frame the choice.
On the lighter end, the 912 is often compared against the UL Power 350i and next to a Jabiru 3300, two popular alternatives in the light sport space. Builders coming from older two-stroke power sometimes look at how the four-stroke 912 stacks up against the two-stroke Rotax 582 before committing.
Pilots used to traditional American powerplants may also want to see how these engines line up with classic Continental and Lycoming options, since those engines still anchor a big slice of general aviation. And if you simply want to know the lineup ranked by power, that ordering makes the climb from the 912 to the 916 easy to picture.
Quick Tip: When comparing across brands, look past horsepower alone. Weight, fuel type, cooling, parts availability, and local mechanic support often matter more to your day-to-day flying than a few extra horses on paper.
Living With a Rotax: Maintenance Basics
Picking the engine is step one. Keeping it healthy is the long game. The good news is that Rotax engines are friendly to maintain, and a lot of routine care falls within reach of an attentive owner working alongside a qualified mechanic.
A few jobs come up again and again on the 912 family and carry over in spirit to the bigger engines:
- Before the first start of the day, many owners practice burping the engine to settle the oil and get an accurate reading.
- On carbureted models, balancing the carburetors keeps the engine smooth and prevents annoying vibration.
- Regular oil care, including changing the oil at the right interval, protects the gearbox and internals.
- Learning the correct starting procedure saves wear and avoids hot-start headaches.
- Knowing how often it needs servicing keeps you ahead of inspections instead of chasing them.
- On the liquid-cooled side, staying current on a coolant change keeps temperatures in check.
The fuel-injected 915 and 916 add a few extra wrinkles, like their fuel-system checks and, for the 916, its dedicated synthetic oil. None of it is exotic, but it does reward an owner who reads the manual and sticks to the schedule.
Ready to find your engine or the parts to keep it running? Browse current Rotax listings and connect with certified aviation services on Flying411 today.
Conclusion
The Rotax 916 vs 915 vs 914 vs 912 decision comes down to matching the engine to the way you actually fly. The 912 is the light, simple, affordable backbone of light aviation. The 914 adds a turbo so you can keep power up high without leaving carburetors behind. The 915 iS modernizes the formula with fuel injection and a real jump in horsepower.
The 916 iS crowns the family with the most power and a 2,000-hour TBO built to last. There is no wrong answer, only the right answer for your mission, your airframe, and your budget.
Take an honest look at your typical altitude, your useful load, and your hours per year, and one of these four will start to feel like the obvious pick. From there, it is just a matter of finding a good example at a fair price.
Compare real Rotax engines, parts, and aviation services in one place at Flying411, where your next powerplant might already be waiting.
Frequently Asked Questions
Are the Rotax 912, 914, 915, and 916 interchangeable in the same airframe?
Not directly. Swapping between them usually means changes to the engine mount, cowling, cooling, and fuel system, and the heavier engines can shift your weight and balance. Always check with your airframe manufacturer before planning an upgrade.
Do these Rotax engines run on regular gas?
Most can use unleaded automotive gasoline that meets the required octane, which is one reason they are popular worldwide. They can also run on 100LL avgas, though leaded fuel tends to increase maintenance, so many owners favor mogas when it is available.
Why does the 916 iS need a different oil than the older engines?
The 916 iS runs at higher internal temperatures and pressures than the 912, 914, and 915, so it calls for a specific fully synthetic oil designed to handle those conditions. Using the older oil that suits the other engines is not recommended for the 916.
Is the 915 iS or 916 iS better for high-altitude airports?
Both hold full takeoff power to roughly 15,000 feet and climb toward a ceiling near 23,000 feet, so both shine in the mountains. The 916 iS has the edge on the hottest, highest days thanks to its extra takeoff power and stronger climb.
How long do Rotax engines typically last before overhaul?
The 912, 914, and 916 carry a 2,000-hour TBO, while the 915 iS has generally carried a shorter figure near 1,200 hours. Actual life depends on how the engine is operated and maintained, and TBO figures can be updated over time, so confirm the current number for your model.
