Output far beyond its size
FourStroke 2.5-20HP
2.5hp5hp8hp9.9hp15hp20hpPortable
Light & Portable
EFI Technology
Easy Maintenance
Introducing FourStroke 2.5-20HP
Put amazing power in the palm of your hand. These compact outboard motors take you to the fun, the fish, or whatever floats your boat – quickly and reliably. Enjoy quick acceleration to go with exhilarating speed. Easy to install and operate, with reliable starting, low vibration, and instant throttle response. It’s worry-free boating at its best.
Intuitive, Innovative Features
Electronic Fuel Injection (EFI)
From the moment you crank the engine to the moment you drop the throttle, EFI technology (on 8 to 20hp outboards) responds with instant power. Surefire starting in all weather conditions. Smooth, efficient acceleration. Maximum fun.
Advanced Tiller
With a range of adjustments, easy-to-reach controls and the flexibility to be set up for left- or right-handed operation (on select models), Mercury tiller handles put you in complete command of your adventures.
Battery-Free EFI
Go farther confidently with battery-free EFI technology, included with manual-start 8 to 20hp outboards. It lets you enjoy the flexibility of portability, without needing to bring along a cranking battery.
Easy Portability
Simple to install and lightweight, 2.5 to 20hp FourStroke outboards let you bring along the fun wherever it’s needed.
FourStroke Performance
Flexible, Versatile Power
A variety of remote and tiller controls, manual and electric start, and power or manual trim (options vary by horsepower) let you set up your engine to match your boat and favorite on-water activities.
Small but Mighty
With their high torque and rugged durability, Mercury portable outboards are ideal for powering a range of johnboats, small aluminum fishing boats and rigid inflatables, as well as for secondary power on sailboats.
Lighter by Design
Proprietary alloys and advanced cowl materials allow Mercury FourStroke outboards to deliver heavyweight performance in a lightweight package.
FourStroke Advantage
Comfort
With a balanced powerhead and sophisticated, vibration-dampening cowl design, Mercury FourStroke outboards deliver an exceptionally smooth and quiet ride at any speed.
Durability
Premium corrosion-preventive technologies and durable components ensure FourStroke outboards can stand up to the most demanding marine environments.
Compact Design
Ideal for new engine setups or repowers, the slender width of a Mercury FourStroke outboard fits most transoms, including those with narrow engine wells and tight motor spacing.
Efficiency
Explore farther and stay out longer thanks to impressive power-to-weight ratios, intelligent fuel systems and optimized fuel injection (on most models) that maximize performance from every drop of fuel.
Specifications
Compare specifications across the FourStroke 2.5-20HP range for your boating needs.
| Specification | FourStroke 2.5HP | FourStroke 5HP | FourStroke 8HP | FourStroke 9.9HP | FourStroke 15HP | FourStroke 20HP |
|---|---|---|---|---|---|---|
| Horsepower | 2.5 | 5 | 8 | 9.9 | 15 | 20 |
| Engine Type | Single | Single | 2-Cylinder | 2-Cylinder | 3-Cylinder | 3-Cylinder |
| Displacement (CID/CC) | 5.7 / 94 | 7.0 / 114 | 13.5 / 221 | 13.5 / 221 | 21.2 / 348 | 21.2 / 348 |
| Dry Weight (Lightest Model) | 34 lbs / 15 kg | 50 lbs / 23 kg | 79 lbs / 36 kg | 79 lbs / 36 kg | 112 lbs / 51 kg | 112 lbs / 51 kg |
| Starting | Manual | Manual / Electric | Manual / Electric | Manual / Electric | Manual / Electric | Manual / Electric |
| Fuel Induction | Carburetor | Carburetor | EFI | EFI | EFI | EFI |
| Controls | Tiller | Tiller / Remote | Tiller / Remote | Tiller / Remote | Tiller / Remote | Tiller / Remote |
| Recommended Fuel | 87 Octane | 87 Octane | 87 Octane | 87 Octane | 87 Octane | 87 Octane |
Warranty & Maintenance
Warranty Coverage
Mercury makes world-class marine products backed by world-class warranties.
Review CoverageMercury Product Protection
Extended service contract for your Mercury engine that covers certain expenses after warranty expires.
Explore BenefitsEasy Maintenance
At Mercury, we make maintenance easy. Learn more about how to keep your Mercury products performing at their peak.
Maintenance & How-To