1986 MerCruiser 5.7 L 350 V8 260 HP Marine Engine

FOR SALE 1986 MerCruiser 5.7 L 350 V8 260 HP Marine Engine NO SALT Drop In Ready 441 HRS. This engine excellent condition and great runs.

The 1986 MerCruiser 5.7L 260 HP is a rugged, marinized General Motors small-block V8. Rated at 260 horsepower, this carbureted powerhouse features a solid torque curve designed for heavy marine applications and is renowned for its exceptional longevity and reliability.

Core Engine Specifications

• Horsepower : 260 HP (at 4400- 4800 RPM at Wide-Open Throttle)
• Displacement : 350 CID (5.7 Liters)
• Configuration : 90-degree V8
• Bore & Stroke : 4.00 in. X 3.48in. (101.6 mm X 88.4 mm)
• Compression Ratio : 9.4: 1

Mechanical & Fuel Details

• Fuel Type : 87 octane gasoline
• Induction : Typically equipped with a 4-barrel marine carburetor (e.g., Rochester Quadrajet)
• Ignition : Thunderbolt IV electronic ignition
• Fuel Pump : Mechanical fuel pump pad (located on the engine block)
• Rear Main Seal : The 1986 model was a transition year; it typically utilizes a 1-piece rear main seal, though some early 1986 models still used a 2-piece seal.

Maintenance & Capacity Specs

• Oil Capacity : 5 to 6 quarts (with filter) of marine-grade engine oil
• Oil Weight : Typically SAE 20W-50 or 25W-40 marine-specific oil
• Operating Temperature : 160 to 170 degrees Fahrenheit
• Spark Plugs : Usually AC Delco MR43T (gap at 0.035in.)