Mercury FourStroke 90 EFI Outboard Motor Price $4,739 Description : Mercury 90 hp Four Stroke. Long shaft. Electric ... while cutting your fuel and maintenance costs. Engine : Engine Type 4 (inline), Horsepower 90 hp (67 kW) at prop, Displacement 105 ... x 82 mm), RPM 5,000 - 6,000, Fuel Induction 4-valves per cylinder, dual overhead cam (DOHC), Electronic Fuel Injection (EFI ...