Mercury Quicksilver 8M0187359 350 MPI Alpha Complete Marine Engine

The Mercury Quicksilver 350 MPI Alpha (MPN 8M0187359) is a fully dressed, drop-in ready marine engine designed for repowering classic sterndrive boats. This 100% new construction engine delivers 300 horsepower at 5000 RPM from a 350 cubic inch (5.7L) displacement, making it the perfect replacement for 5.0L, 5.7L, and 350 carbureted or fuel-injected engines in boats built before 2008 (California) or 2010 (other states).

Key Engine Features:

• Cast iron engine block and Quicksilver cast iron cylinder heads with screw-in rocker studs
• Black-X valve technology provides 42% reduction in valve wear versus traditional stainless steel valves
• Multi-port fuel injection (MPI) using Cool Fuel II system for improved fuel economy and throttle response
• Raw water cooling with warm exhaust manifolds and flush system
• Roller camshaft and 1.5:1 stamped rocker arms
• ECM 555 engine control module with Engine Guardian protection
• SmartCraft ready with 10-pin harness for digital gauge compatibility
• Mechanical throttle and shift controls for easy installation
• Dry joint exhaust system
• Special flame graphics

Performance Specifications:

• 300 HP at the propeller (325 HP at crankshaft)
• Full throttle RPM range: 4600-5000
• Runs on 87 octane fuel
• 65 amp alternator (917 watts)
• Bore and stroke: 4.03 x 3.48 inches

This engine is designed for Alpha One sterndrive applications and comes with a 3-year limited factory warranty. Compatible with both analog cable controls and SmartCraft digital gauges. As a complete repower solution, this is EPA and CARB compliant—the old engine must be returned per EPA regulation 1068.240.

Important Note: If used with an Alpha One Gen I drive, this engine requires Seawater Pump Kit 46-8M0139983 and serpentine belt 57-865615Q03 (sold separately) for proper cooling.