The Honda BF40 and BF50 combine Honda’s proven four-stroke engineering with the latest outboard technology, resulting in the lightest, most compact engines in their class. Key performance features include BLAST (Boosted Low Speed Torque) for dramatically improved acceleration and hole shot, Programmed Electronic Fuel Injection for easy starts and instant throttle response, and Lean Burn Control, which allows a leaner air-to-fuel mixture and cuts fuel use by up to 20% compared to competitors at cruising speed. A high-performance gearcase reduces drag and hull porpoising, while a lightweight Mikuni intake system builds low-end torque — together making these engines a strong fit for aluminum boats, inflatables, skiffs, and flats boats.

Reliability and convenience are equally strong. Both engines carry Honda’s transferable, non-declining True 5 Warranty, along with an Engine Alert System that uses visual, audio, and RPM-reduction alerts to flag overheating, low oil pressure, or over-revving. A multi-layered corrosion protection system and fresh water flushport help the engines hold up in saltwater use, and a high-output 22-amp alternator delivers nearly double the charging power of competing engines — useful for running electronics and onboard systems, which can also interface via NMEA 2000 connectivity for GPS or sonar displays.

For everyday use, the BF40 and BF50 offer easy-access side-mounted oil filters and screw-type valve adjusters to simplify maintenance, plus a fishing-friendly design with a 3-position, center-mounted tiller handle, adjustable throttle and steering friction, and optional features like variable trolling speed and power trim/tilt (with a -4° to +16° trim range and 63° tilt range) for added performance and handling control.

EngineBF40BF50
Type4-Stroke SOHC, 3 Cylinder, 2 Valves/Cyl.4-Stroke SOHC, 3 Cylinder, 2 Valves/Cyl.
Displacement808 cc (49.4 cubic inches)808 cc (49.3 cubic inches)
Bore & Stroke70 mm x 70 mm (2.8 x 2.8 inches)70 mm x 70 mm (2.8 x 2.8 inches)
Full Throttle RPM Range5,000-6,000 RPM5,500-6,000 RPM
Rated Power40 HP @ 5,500 RPM50 HP @ 6,000 RPM
Cooling SystemWater CooledWater Cooled
Fuel DeliveryProgrammed Fuel InjectionProgrammed Fuel Injection
Ignition SystemMicroComputer ProgrammedMicroComputer Programmed
Starting SystemElectricElectric
ExhaustThrough HubThrough Hub
LubricationWet SumpWet Sump
Trim Range-4° to +16°-4° to +16°
Tilt Range63°63°
DriveBF40BF50
Gear Ratio2.08:12.08:1
Gear ShiftF-N-RF-N-R
EquipmentBF40BF50
Alternator with voltage regulator22-Amp (275 watt)22-Amp (275 watt)
Battery Charging Power17 Amps17 Amps
PropellerOptionalOptional
Power TiltNANA
Power Trim & TiltAvailableAvailable
Gas Assisted TiltAvailableAvailable
Oil Pressure AlertStandardStandard
Temperature AlertStandardStandard
Rev-LimiterStandardStandard
Speedometer PickupStandardStandard
WarrantyBF40BF50
Recreational5 years5 years
Commercial/Rental2 years2 years
Optional ExtendedUp to 36 months Up to 36 months 
DimensionsBF40BF50
Overall Width372 mm/14.7 inches372 mm/14.7 inches
Transom HeightBF40BF50
L Type508 mm/20 inches508 mm/20 inches
X TypeNA635 mm/25 inches
Dry WeightBF40BF50
L-Type97 kg/214 lbs.97 kg/214 lbs.
X-TypeNA101 kg/223 lbs.