Our 139-cc 4-hp portable outboard mirrors our OHV F6, with a couple less horses. It features the same ergonomic, easy-grip starter handle with a built-in decompression device for effortless starts. The F4 also features a built-in fuel tank with the option of switchable access to an additional external tank for amazing extended range. There’s no stopping this little brute.

Features:

• Only 60 pounds
• Shaft Length - 15"
• Solid 6-amp alternator
• Manual Start Only

Easy Operation

The F6, F4 and F2.5 feature built-in, see through fuel tanks. The F6 and F4 also feature switchable access to an optional, 3.1-gallon external fuel tank for extended range.

Wet Sump

A pressurized oil delivery system that incorporates a compact and durable oil pump to keep all of the moving parts of their Overhead Valve systems lubricated and running smoothly for maximum reliability.

Maximum Efficiency

The F6, F4 and F2.5 have a carburetor with a factory-selected setting for maximum efficiency. Additionally, automatic decompression, built-in auxiliary priming and start-in-gear prevention help make for easier starts.

Corrosion Protection

Combined with our proprietary alloy (YDC-30), our exclusive Phaze Five electro-deposited, anti-corrosive paint system provides a tough, five-layer barrier against corrosion. This protection is standard on all Yamaha Portable outboards.

Lightweight, Portable Power

They may weigh as little as 37 pounds, but these Overhead-Valve portable outboards are packed with features that create smooth, quiet power. This includes a CDI or TCI ignition system, an optimally balanced crankshaft, a long span mounting system and a labyrinth exhaust. 

Surprising Performance

The portable F6, F4 and F2.5 all offer impressive features like electronic ignition, thermostatic cooling and 180-degree steering.

Record Setting Fuel Efficiency

Small motors use less fuel, but according to the Guinness Book of World Records, the Yamaha F4 actually set a world record for fuel efficiency, traveling 67.27 continuous statute miles on one gallon of gas.

Weight †	27 kg (60 lbs) - 28 kg (61 lbs)
Full Throttle RPM Range	4000 ~ 5000
Fuel Induction System	Carb
Recommended Engine Oil	Yamalube® 4M (See owner's manual)
Engine Type	1 cyl
Displacement	139cc
Bore x Stroke	62 x 46mm (2.44 x 1.81in)
Prop Shaft Horsepower	4hp at 4500 rpm
Alternator Output at W.O.T.	6 Amp
Compression Ratio	8.9:1
Recommended Fuel	Octane 87
Recommended Fuel Filtration	N/A
C.A.R.B. Rating	3-Star
Exhaust	Above Propeller
Intake	2
Ignition	CDI
Spark Plug	CR6HSB
Starting System	Manual
Lubrication	Wet Sump
Engine Oil Capacity	0.6L
Recommended Cooling	Thermostatic Control
Ethanol Blend Limit	10% Maximum
Gear Ratio	2.08:1
Gear Shift	Forward, Neutral, Reverse
Shaft Length	15"
Degree of Tilt	69°
Degree of Trim	-4° through +16°
Mounting Centers	N/A
Steering	Tiller
Steering Angle (maximum)	90° from center, either direction
Warranty	Limited 3-Year Pleasure, 3-Year Government, 1-Year Commercial