Portable 4 hp

Engine Type 1 cyl
Displacement 139cc
Bore x Stroke 62 x 46mm (2.44 x 1.81in)
Prop Shaft Horsepower 4hp at 4500 rpm
Full Throttle RPM Range 4000 ~ 5000
Alternator Output at W.O.T. 6 Amp
Compression Ratio 8.9:1
Fuel Induction System Carb
Weight* 27 kg (59 lbs) – 28 kg (61 lbs)
Recommended Fuel Octane 87
Recommended Engine Oil Yamalube® 4M (See owner’s manual)
Recommended Fuel Filtration N/A
C.A.R.B. Rating 3-Star
Exhaust Above Propeller
Intake 2
Ignition CDI
Spark Plug CR6HSB
Alternator Output 6 Amp
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″ – 20″
Degree of Tilt 69°
Degree of Trim -4° through +16°
Dry Weight 15″ shaft / 27 kg (59 lbs), 20″ shaft / 28 kg (61 lbs)
Mounting Centers N/A
Steering Angle (maximum) 90° from center, either direction
Warranty Limited 3-Year Pleasure, 3-Year Government, 1-Year Commercial



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.

  • Tiller-handle control with forward-neutral-reverse shifting and an ergonomic twist-grip throttle
  • Only 59 pounds (15” shaft model)
  • Available in 15” and 20” shaft lengths
  • Solid 6-amp alternator


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