Home  ›  FourStroke 2.5-25HP

FourStroke 2.5-25hp

Output far beyond its size

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.

See All Specifications

Features

START FAST. FINISH STRONG.

No matter what you do out on the water, it's nice to have the kind of power that blows your hat off now and then.

The kind of power that gets you up on plane quicker. Gets you out there faster. And gets you home in record time.

Performance-Inspired Configuration:The four-valve, dual-overhead-cam design delivers greater acceleration.

Adaptive Speed Control (ASC):Maintains engine speed (rpm) regardless of load or condition changes—without having to frequently adjust throttle position.

Advanced Hydrodynamics:The FourStroke’s gearcase is designed to reduce drag and deliver more stable, high-speed performance.

LIGHT AND MIGHTY.

Mercury engineers worked hard to cut every possible pound from our FourStroke engines for enhanced portability and improved performance.

Advanced Range Optimization (ARO) and Closed-Loop Fuel Control: Work together to adjust the fuel mixture and deliver the best possible fuel efficiency.

Premium Power and Torque: Big, bold power in a lightweight package delivers better maneuverability, greater acceleration, and maximum exhilaration.

26-inch Mounting Centers: The FourStroke’s narrow, 64-degree bank angle and single-point cowl latch system enable a tighter fit to the engine block for a smaller profile.

SPECIFICATIONS

  • 25 EFI
  • 20 EFI
  • 15 EFI
  • 9.9
  • 8
  • 6
  • 5
  • 5 SailPower
  • 4
  • 3.5
  • 2.5

FourStroke 25 EFI

HP / kW
  • 25 / 18.6
Engine type
  • Inline 3
Displacement (CID/CC)
  • 32.1 / 526
Full throttle RPM
  • 5000-6000
Fuel induction system
  • 2 valves per cylinder, single overhead cam (SOHC)
Alternator amp / Watt
  • 15 amp / 186 watt
Recommended fuel
  • 87% octane / up to 10% ethanol
Recommended oil
  • Mercury FourStroke Oil 10W-30
Engine protection operator warning system
  • Low oil pressure
  • Over-rev
  • Overheat
  • Sensor failure
Starting
  • Electric (turn-key)
  • Manual
Steering
  • Remote
  • Tiller
Shaft length
  • 15" / 381 mm
  • 20" / 508 mm
Gearcase ratio
  • 1.92:1
Dry weight *Lightest model available
  • 157 lbs / 71 kg
CARB star rating
  • 3
Bore and stroke
  • 2.40 x 2.36" / 61 x 60 mm
Ignition
  • CDI w/electronic spark advance
Fuel system
  • Electronic Fuel Injection (EFI)
Cooling system
  • Water-cooled with thermostat
Gear shift
  • F-N-R
Gearcase options
  • Standard
Trim system
  • Manual
  • Power Trim
Exhaust system
  • Through prop
Shallow water trim range (degrees)
  • 16
Remote fuel tank standard (gal / L)
  • 6.6 / 25
Color
  • Phantom Black

FourStroke 20 EFI

HP / kW
  • 20 / 14.7
Engine type
  • Inline 2
Displacement (CID/CC)
  • 20.3 / 333
Full throttle RPM
  • 5700 - 6200
Fuel induction system
  • Single Overhead Cam
Alternator amp / Watt
  • 12/145 electric
Recommended fuel
  • 87% octane / up to 10% ethanol
Recommended oil
  • 25W-40 Synthetic Blend
  • Mercury FC-W 10W-30 4-Stroke Marine Oil
Engine protection operator warning system
  • Low oil pressure
  • Low water pressure
  • Over-rev
  • Overheat
  • Sensor failure
Starting
  • Electric
  • Manual
Steering
  • Remote
  • Tiller
Shaft length
  • 15" / 381 mm
  • 20" / 508 mm
Gearcase ratio
  • 2.15:1
Dry weight *Lightest model available
  • 99 lbs / 45 kg
CARB star rating
  • 3
Bore and stroke
  • 2.40 x 2.24" / 61 x 57 mm
Ignition
  • CDI w/electronic spark advance
Fuel system
  • Electronic Fuel Injection (EFI)
Cooling system
  • Water-cooled with thermostat
Gear shift
  • F-N-R
Gearcase options
  • Standard
Trim system
  • Manual
  • Power Tilt
Trim positions
  • 6
Exhaust system
  • Through prop
Shallow water drive
  • Yes
Shallow water trim range (degrees)
  • 16
Remote fuel tank (optional)
  • Yes
Remote fuel tank standard (gal / L)
  • 6.6 / 25
Color
  • Phantom Black

FourStroke 15 EFI

HP / kW
  • 15 / 11.1
Engine type
  • Inline 2
Displacement (CID/CC)
  • 20.3 / 333
Full throttle RPM
  • 5700 - 6200
Fuel induction system
  • 2 valves per cylinder, single overhead cam (SOHC)
Alternator amp / Watt
  • 12/145 electric
Recommended fuel
  • 87 octane compatible (up to 10% ethanol)
Recommended oil
  • 25W-40 Synthetic Blend
  • Mercury FC-W 10W-30 4-Stroke Marine Oil
Engine protection operator warning system
  • Low oil pressure
  • Over-rev
  • Overheat
  • Sensor failure
Starting
  • Electric
  • Manual
Steering
  • Remote
  • Tiller
Shaft length
  • 15" / 381 mm
  • 20" / 508 mm
Gearcase ratio
  • 2.15:1
Dry weight *Lightest model available
  • 99 lbs / 45 kg
CARB star rating
  • 3
Bore and stroke
  • 2.40 x 2.24" / 61 x 57 mm
Ignition
  • CDI w/electronic spark advance
Fuel system
  • Electronic Fuel Injection (EFI)
Cooling system
  • Water-cooled with thermostat
Gear shift
  • F-N-R
Gearcase options
  • Standard
Trim system
  • Manual
  • Power Tilt
Trim positions
  • 6
Exhaust system
  • Through prop
Shallow water drive
  • Yes
Shallow water trim range (degrees)
  • 16
Remote fuel tank (optional)
  • Yes
Remote fuel tank standard (gal / L)
  • 6.6 / 25
Color
  • Phantom Black

FourStroke 9.9

HP / kW
  • 9.9 / 7.3
Engine type
  • Inline 2
Displacement (CID/CC)
  • 12.8 / 208
Full throttle RPM
  • 5000-6000
Fuel induction system
  • 2 valves per cylinder, single overhead cam (SOHC)
Alternator amp / Watt
  • 6 amp / 76 watt
Recommended fuel
  • 87% octane / up to 10% ethanol
Recommended oil
  • Mercury FourStroke Oil 10W-30
Engine protection operator warning system
  • Low oil pressure
  • Over-rev
Starting
  • Electric
  • Manual
Steering
  • Remote
  • Tiller
Shaft length
  • 15" / 381 mm
  • 20" / 508 mm
  • 25" / 635 mm (CT model)
Gearcase ratio
  • 2.08:1 or 2.42:1 (CT model)
Dry weight *Lightest model available
  • 84 lbs / 38 kg
CARB star rating
  • 3
Bore and stroke
  • 2.16 x 1.73" / 55 x 44 mm
Ignition
  • CDI w/electronic spark advance
Fuel system
  • Carbureted
Cooling system
  • Water-cooled with thermostat
Gear shift
  • F-N-R
Gearcase options
  • Command Thrust (CT)
  • Standard
Trim system
  • Power Tilt (CT model)
Trim positions
  • Ratcheting
Exhaust system
  • Through prop
Shallow water drive
  • Yes
Shallow water trim range (degrees)
  • 16
Remote fuel tank standard (gal / L)
  • 3.2 / 12
Color
  • Phantom Black

FourStroke 8

HP / kW
  • 8 / 5.9
Engine type
  • Inline 2
Displacement (CID/CC)
  • 12.8 / 208
Full throttle RPM
  • 5000-6000
Fuel induction system
  • 2 valves per cylinder, single overhead cam (SOHC)
Alternator amp / Watt
  • 6 amp / 76 watt
Recommended fuel
  • 87% octane / up to 10% ethanol
Recommended oil
  • Mercury FourStroke Oil 10W-30
Engine protection operator warning system
  • Low oil pressure
  • Over-rev
Starting
  • Electric
  • Manual
Steering
  • Tiller
Shaft length
  • 15" / 381 mm
  • 20" / 508 mm
Gearcase ratio
  • 2.08:1
Dry weight *Lightest model available
  • 84 lbs / 38 kg
CARB star rating
  • 3
Bore and stroke
  • 2.16 x 1.73" / 55 x 44 mm
Ignition
  • CDI w/electronic spark advance
Fuel system
  • Carbureted
Cooling system
  • Water-cooled with thermostat
Gear shift
  • F-N-R
Gearcase options
  • Standard
Trim positions
  • Ratcheting
Exhaust system
  • Through prop
Shallow water drive
  • Yes
Shallow water trim range (degrees)
  • 16
Remote fuel tank standard (gal / L)
  • 3.2 / 12
Color
  • Phantom Black

FourStroke 6

HP / kW
  • 6 / 4.4
Engine type
  • 1 cylinder
Displacement (CID/CC)
  • 7.5 / 123
Full throttle RPM
  • 5000-6000
Fuel induction system
  • 2-valve pushrod (overhead valve)
Recommended fuel
  • 87% octane / up to 10% ethanol
Recommended oil
  • Mercury FourStroke Oil 10W-30
Engine protection operator warning system
  • Low oil pressure
  • Over-rev
Starting
  • Manual
Steering
  • Tiller
Shaft length
  • 15" / 381 mm
  • 20" / 508 mm
Gearcase ratio
  • 2.15:1
Dry weight *Lightest model available
  • 57 lbs / 26 kg
CARB star rating
  • 3
Bore and stroke
  • 2.32 x 1.77" / 59 x 45 mm
Ignition
  • CDI w/electronic spark advance
Fuel system
  • Carbureted
Cooling system
  • Water-cooled with thermostat
Gear shift
  • F-N-R
Gearcase options
  • Standard
Trim positions
  • 6
Exhaust system
  • Through prop
Shallow water drive
  • Yes
Shallow water trim range (degrees)
  • 16
Integrated fuel tank (gal / L)
  • 0.3 / 1.1
Optional fuel tank (gal / L)
  • 3.2 / 12
Color
  • Phantom Black

FourStroke 5

HP / kW
  • 5 / 3.7
Engine type
  • 1 cylinder
Displacement (CID/CC)
  • 7.5 / 123
Full throttle RPM
  • 4500-5500
Fuel induction system
  • 2-valve pushrod (overhead valve)
Recommended fuel
  • 87% octane / up to 10% ethanol
Recommended oil
  • Mercury FourStroke Oil 10W-30
Engine protection operator warning system
  • Low oil pressure
  • Over-rev
Starting
  • Manual
Steering
  • Tiller
Shaft length
  • 15" / 381 mm
  • 25" / 635 mm
Gearcase ratio
  • 2.15:1
Dry weight *Lightest model available
  • 57 lbs / 26 kg
CARB star rating
  • 3
Bore and stroke
  • 2.32 x 1.77" / 59 x 45 mm
Ignition
  • CDI w/electronic spark advance
Fuel system
  • Carbureted
Cooling system
  • Water-cooled with thermostat
Gear shift
  • F-N-R
Gearcase options
  • Standard
Trim positions
  • 6
Exhaust system
  • Through prop
Shallow water drive
  • Yes
Shallow water trim range (degrees)
  • 16
Integrated fuel tank (gal / L)
  • 0.3 / 1.1
Optional fuel tank (gal / L)
  • 3.2 / 12
Color
  • Phantom Black

FourStroke 5 SailPower

HP / kW
  • 5 / 3.7
Engine type
  • 1 cylinder
Displacement (CID/CC)
  • 7.5 / 123
Full throttle RPM
  • 4500-5500
Fuel induction system
  • 2-valve pushrod (overhead valve)
Alternator amp / Watt
  • 4 amp / 50 watt lighting and charging
Recommended fuel
  • 87% octane / up to 10% ethanol
Recommended oil
  • Mercury FourStroke Oil 10W-30
Engine protection operator warning system
  • Low oil pressure
  • Over-rev
Starting
  • Manual
Steering
  • Tiller
Shaft length
  • 20" / 508 mm
Gearcase ratio
  • 2.15:1
Dry weight *Lightest model available
  • 59 lbs / 27 kg
CARB star rating
  • 3
Bore and stroke
  • 2.32 x 1.77" / 59 x 45 mm
Ignition
  • CDI w/electronic spark advance
Fuel system
  • Carbureted
Cooling system
  • Water-cooled with thermostat
Gear shift
  • F-N-R
Gearcase options
  • Standard
Trim positions
  • 6
Exhaust system
  • Through prop
Shallow water drive
  • Yes
Shallow water trim range (degrees)
  • 16
Integrated fuel tank (gal / L)
  • 0.3 / 1.1
Optional fuel tank (gal / L)
  • 3.2 / 12
Color
  • Phantom Black

FourStroke 4

HP / kW
  • 4 / 2.9
Engine type
  • 1 cylinder
Displacement (CID/CC)
  • 7.5 / 123
Full throttle RPM
  • 4500-5500
Fuel induction system
  • 2-valve pushrod (overhead valve)
Recommended fuel
  • 87% octane / up to 10% ethanol
Recommended oil
  • Mercury FourStroke Oil 10W-30
Engine protection operator warning system
  • Low oil pressure
  • Over-rev
Starting
  • Manual
Steering
  • Tiller
Shaft length
  • 15" / 381 mm
  • 20" / 508 mm
Gearcase ratio
  • 2.15:1
Dry weight *Lightest model available
  • 57 lbs / 26 kg
CARB star rating
  • 3
Bore and stroke
  • 2.32 x 1.77" / 59 x 45 mm
Ignition
  • CDI w/electronic spark advance
Fuel system
  • Carbureted
Cooling system
  • Water-cooled with thermostat
Gear shift
  • F-N-R
Gearcase options
  • Standard
Trim positions
  • 6
Exhaust system
  • Through prop
Shallow water drive
  • Yes
Shallow water trim range (degrees)
  • 16
Integrated fuel tank (gal / L)
  • 0.3 / 1.1
Optional fuel tank (gal / L)
  • 3.2 / 12
Color
  • Phantom Black

FourStroke 3.5

HP / kW
  • 3.5 / 2.6
Engine type
  • 1 cylinder
Displacement (CID/CC)
  • 5.2 / 85
Full throttle RPM
  • 5000-6000
Fuel induction system
  • 2-valve pushrod (overhead valve)
Recommended fuel
  • 87% octane / up to 10% ethanol
Recommended oil
  • Mercury FourStroke Oil 10W-30
Engine protection operator warning system
  • Over-rev
Starting
  • Manual
Steering
  • Tiller with 360° turning
Shaft length
  • 15" / 381 mm
  • 20" / 508 mm
Gearcase ratio
  • 2.15:1
Dry weight *Lightest model available
  • 41 lbs / 18 kg
CARB star rating
  • 3
Bore and stroke
  • 2.16 x 1.42" / 55 x 36 mm
Ignition
  • CDI w/electronic spark advance
Fuel system
  • Carbureted
Cooling system
  • Water-cooled with thermostat
Gear shift
  • F-N
Gearcase options
  • Standard
Trim system
  • 4 position
Trim positions
  • 4
Exhaust system
  • Above prop
Shallow water trim range (degrees)
  • 16
Integrated fuel tank (gal / L)
  • 0.3 / 1.1
Color
  • Phantom Black

FourStroke 2.5

HP / kW
  • 2.5 / 1.9
Engine type
  • 1 cylinder
Displacement (CID/CC)
  • 5.2 / 85
Full throttle RPM
  • 4500-5500
Fuel induction system
  • 2-valve pushrod (overhead valve)
Recommended fuel
  • 87 octane compatible (up to 10% ethanol)
Recommended oil
  • Mercury FourStroke Oil 10W-30
Engine protection operator warning system
  • Over-rev
Starting
  • Manual
Steering
  • Tiller with 360° turning
Shaft length
  • 15" / 381 mm
Gearcase ratio
  • 2.15:1
Dry weight *Lightest model available
  • 41 lbs / 18 kg
CARB star rating
  • 3
Bore and stroke
  • 2.16 x 1.42" / 55 x 36 mm
Ignition
  • CDI w/electronic spark advance
Fuel system
  • Carbureted
Cooling system
  • Water-cooled with thermostat
Gear shift
  • F-N
Gearcase options
  • Standard
Trim system
  • 4 position
Trim positions
  • 4
Exhaust system
  • Above prop
Shallow water trim range (degrees)
  • 16
Integrated fuel tank (gal / L)
  • 0.3 / 1.1
Color
  • Phantom Black
Go Back Contact Us

Sign up for Nautical Ventures EMAIL UPDATES & PROMOTIONS

Ft. Lauderdale
Map
Ft. Lauderdale Marina
Map
Palm Beach
Map
Riviera Beach
Map
Stuart
Map
Tampa Bay
Map
Sarasota
Map
APALACHICOLA
Map
  Text Us!