F4 Specifications

Engine TypeOne-Cylinder
Displacement8.5 ci (139 cc)
Bore x Stroke62 x 46mm (2.44 x 1.81 in)
Prop Shaft Horsepower4hp at 4500 rpm
Compression Ratio8.9:1
Fuel/Induction SystemOHV
ExhaustAbove Propeller
Ignition SystemCDI
Spark PlugCR6HSB-000-000
Alternator Output6 Amp (Optional: Requires Charging Kit
Starting SystemManual
LubricationWet Sump
Engine Oil Capacity.6L (.63 qt)
Full Throttle RPM Range4000-5000
CoolingWater/Thermostatic Control
Recommended Engine OilYamalube® 4M (See owner's manual)
Recommended FuelRegular Unleaded (Minimum Pump Octane 87)
Recommended Fuel FiltrationYamaha Mini 10-Micron Fuel/Water Separating Filter (external)
Ethanol Blend Limit10% Maximum
Gear Ratio(27:13) 2.08:1
Gear ShiftForward, Neutral, Reverse
Shaft LengthS=15" L=20"
Degree of Tilt69°
Degree of Trim5 positions
C.A.R.B. Rating3-Star
Dry WeightF4SMHA = 27kg (60 lbs), F4LMHA = 28kg (62 lbs)
Steering Angle (maximum)90° from center, either direction
Warranty3-year Pleasure, 3-year Government, 1-year Commercial