As a rule of thumb, outboard motors feature 1-12 cylinders depending on the make and model. To be more precise, the number of cylinders in each outboard category is as follows:
- Portable (2.3-6 HP): 1 cylinder
- Portable (8-25 HP): 2 cylinders
- Midrange (25-60 HP): 3-4 cylinders
- Midrange and high-performance (75-150 HP): 4 cylinders
- High-performance (175-300 HP): 4-8 cylinders
- High-performance (350-600+ HP): 6-12 cylinders
If you want to find out more about the engine architecture of different outboard motor families, this post is for you.
We at PowerSportsGuide have compiled all you need to know under one roof!
How Many Cylinders does an Outboard Motor Have?
How Many Cylinders does a 2.3-6 HP Outboard Have?
The smallest outboard motors are the lightweight 2.3-6 HP models, which are exclusively powered by single-cylinder engines.
Entry-level models in this breed are the 2.3-2.5 HP models with a displacement of 52-127cc, while 2-6 HP outboards displace anywhere from 123-209cc.
How Many Cylinders does an 8-20 HP Outboard Have?
It’s safe to say that almost every 8-20 HP outboard motor has a twin-cylinder engine.
Unlike their single-cylinder counterparts, these units ensure a smoother operation and more torque.
The smallest twin-cylinder outboards are the 8 HP models, which typically utilize de-tuned 10 HP engines with a displacement of 208-222cc.
In contrast, the displacement of the 10-20 HP class averages between 208 and 432cc.
How Many Cylinders does a 25 HP Outboard Have?
Interestingly, 25 HP outboards are available with both twin- and triple-cylinder engines.
Yamaha markets its F25 as the most powerful portable outboard motor. This unit is powered by a 4-stroke, 432cc twin, pretty much the same as you will find in its 20 HP sibling.
In contrast, all other manufacturers offer their 25 HP outboards with triple engines, displacing between 489 and 552cc.
How Many Cylinders does a 30 HP Outboard Have?
30 HP outboards are exclusively available with inline 3-cylinder engines. The capacity of these power sources varies greatly but falls into the ballpark of 489-747cc.
This is because certain models like the Yamaha F30 feature a de-tuned 40 HP engine, while its competitors are powered by unrestricted engines designed for the 25-30 HP power band.
As a reference, here are some popular 30 HP outboard engines:
- Yamaha: 747cc, 3-cylinder (30, 40 HP)
- Honda: 552cc, 3-cylinder (25, 30 HP)
- Tohatsu: 526cc, 3-cylinder (25, 30 HP)
- Mercury: 500cc, 3-cylinder (25, 30 HP)
- Suzuki: 489cc, 3-cylinder (25, 30 HP)
How Many Cylinders does a 40-50 HP Outboard Have?
Interestingly, 40-50 HP outboard engines come with both 3- and 4-cylinder, 747-995cc engines.
The most common power sources in this breed are as follows:
- Yamaha: 747cc, 3-cylinder (30, 40 HP)
- Tohatsu: 866cc, 3-cylinder (40, 50 HP)
- Honda: 808cc, 3-cylinder (40, 50 HP)
- Yamaha: 996cc, 4-cylinder (50, 60 HP)
- Mercury: 995cc, 4-cylinder (40, 50, 60 HP)
- Suzuki: 941cc, 3-cylinder (40, 50, 60 HP)
How Many Cylinders does a 60 HP Outboard Have?
Like the 50 HP family, 60 HP outboards are also available with 3-cylinder, and inline 4-cylinder engines.
Engines of the most popular models in this breed are as follows:
- Suzuki: 941cc, 3-cylinder (40, 50, 60 HP)
- Mercury: 995cc, 3-cylinder (40, 50, 60 HP)
- Yamaha: 996cc, 4-cylinder (50, 60 HP)
- Honda: 998cc, 3-cylinder (60 HP)
- Tohatsu: 998cc, 3-cylinder (60 HP)
How Many Cylinders does a 75-150 HP Outboard Have?
75-150 HP outboards are typically powered by inline 4-cylinder engines.
In terms of valves, the industry standard is 4 valves per cylinder, so these power mills typically utilize 16 valves.
One exception is the Mercury 4-cylinder outboard engine designed with 8 valves (2 valves per cylinder).
When it comes to cam setup, outboards of this size can feature both SOHC and DOHC configurations.
Average displacements within each major category are as follows:
- 75-100 HP: 1496-2065cc
- 115-140 HP: 1832-2054cc
- 150 HP: 2354-2999cc
How Many Cylinders does a 175-200 HP Outboard Have?
Engine sizes and configurations in this breed vary greatly.
As a rule of thumb, 175-200 HP outboard engines are powered by inline 4-cylinder, V6, or V8 engines.
The smallest 4-cylinder models have smaller displacements of 2670-2867cc, while their V6 brothers displace around 3500cc.
The largest 200 HP outboards are manufactured by Mercury. These beasts utilize a de-tuned 4572cc, V8 engine with 225-300 HP.
How Many Cylinders does a 225-300 HP Outboard Have?
You can find V6 or V8 engines in most 225-300 HP outboards, displacing between 3471 and 4572cc.
The most common power sources in this class are as follows:
- Honda: 3583cc, V6
- Suzuki: 3614cc, 4028cc, 4390cc, V6
- Tohatsu: 3471cc, 3583cc, V6
- Yamaha: 4169cc, V6
- Mercury: 4572cc, V8
How Many Cylinders does a 350-450 HP Outboard Have?
350-450 HP outboards are designed with V6, V8, and V10 engines, displacing between 4390 and 5559cc.
The entry-level engine in this line is planted in 350 HP Suzuki outboards. This 4390cc, V6 power mill is an unleashed version of its 300 HP sibling.
On the other end of the spectrum, you can find the 5719cc, V10 Mercury engine, which is rated at 350 or 400 HP depending on the model.
How Many Cylinders does a 500-600 HP Outboard Have?
You can find 8-12 cylinders in the massive engines of 400-600 HP outboards.
One of the most well-known series is the Mercury 12V Verado designed with an amazing, 7554cc, V12 power mill.
One of their very few competitors is the Seven Marine 627sv, powered by a V8, 6162cc engine rated at 627 HP.
Outboard Motor Cylinder Chart
For your convenience, we’ve compiled the key specs of the most common outboard motor categories into one Outboard Motor Cylinder Chart:
| HP | Cylinders | Displacement (cc) |
| 2.3 HP | 1 | 52cc |
| 2.5 HP | 1 | 37-127cc |
| 3.5 HP | 1 | 85cc |
| 4 HP | 1 | 123-139cc |
| 5 HP | 1 | 123cc |
| 6 HP | 1 | 139-209cc |
| 8 HP | 2 | 208-222cc |
| 10 HP | 2 | 208-362cc |
| 15 HP | 2 | 327-362cc |
| 20 HP | 2 | 327-432cc |
| 25 HP | 2/3 | 432-552cc |
| 30 HP | 3 | 489-474cc |
| 40 HP | 3/4 | 747-995cc |
| 50 HP | 3/4 | 808-995cc |
| 60 HP | 3/4 | 941-995cc |
| 70 HP | 4 | 996-1502cc |
| 75 HP | 4 | 1496-2065cc |
| 80 HP | 4 | 1496-2065cc |
| 90 HP | 4 | 1496-2065cc |
| 100 HP | 4 | 1496-2065cc |
| 115 HP | 4 | 1832-2354cc |
| 135 HP | 4 | 2354cc |
| 140 HP | 4 | 1995-2054cc |
| 150 HP | 4 | 2354-2785cc |
| 175 HP | 4/V6 | 2785-3471cc |
| 200 HP | 4/V6 | 2785-4572cc |
| 225 HP | 4/V6/V8 | 3471-4572cc |
| 250 HP | V6/V8 | 3583-4572cc |
| 300 HP | V6/V8 | 4028-4572cc |
| 350 HP | V6/V10 | 4390-5719cc |
| 400 HP | V10 | 5719cc |
| 425 HP | V8 | 5559cc |
| 450 HP | V8 | 5559cc |
| 500 HP | V12 | 7554cc |
| 600 HP | V12 | 7554cc |
Disclaimer: This chart is for informational purposes only! For more information, please check the official factory manuals.
Takeaways
Portable outboard motors are powered by single-cylinder (2.3-6 HP) or twin-cylinder (8-25 HP) engines.
The power sources of the smaller (25-60 HP) mid-sized outboards feature 3-4 cylinders while their larger brothers (75-150 HP) exclusively have an inline 4-cylinder architecture.
The large-size or high-performance outboards (175-600 HP) are typically designed with V6, V8, V10, and V12 engines, but entry-level models in this breed borrow their inline 4-cylinder engines from the mid-size class.
References:
Yamaha outboards, Mercurymarine, Tohatsu, Marine.honda, Suzukimarine
