MerCruiser 350 MPI Sterndrive Marine Engine Package

Description

Experience dependable marine thrust by installing the MerCruiser 350 MPI Sterndrive Marine Package inside commercial passenger launches and coastal cruisers. The 5.7L 90° V8 engine generates 300BHP through multi-port electronic injection. Operating in open raw seawater demands routine chemical flushing and sacrificial anode replacements to prevent galvanic mineral build-up across internal exhaust cooling jackets.

High-density cast iron forms the parent-bore cylinder block and 2 Vortec overhead-valve cylinder heads. A 12V marine electrical network includes a 65A alternator, high-torque starter, and ECM 555 computer harness. Dry engine mass weighs 935 lbs with a base mounting envelope measuring 32.0in long by 29.1in wide and 22.0in high. The lube oil pan holds 1.24 US gal and the cooling passages hold 3.96 US gal.

Key Features of MerCruiser 350 MPI Sterndrive

Tour boat operators buy MerCruiser 350 MPI Sterndrive packages to repower aging runabouts with modern fuel injection. The installation kit integrates with transom plates and power steering systems for clean engine rigging.

• Multiport fuel injection meters precise fuel charges under SmartCraft ECM 555 control.
• The universal sterndrive bellhousing connects to MerCruiser transom plate assemblies.
• A heavy-duty marine engine coupler absorbs rotational pulses from the 14in flywheel.
• The hydraulic power steering actuator reduces steering helm load under full acceleration.
• Overhead valve cylinder heads house 2-Valves per cylinder for dependable valve train life.
• The cast aluminum intake plenum feeds equal air flow to all 8 intake ports.
• Integrated cast iron cylinder walls eliminate loose liner shifting under severe duty cycles.
• The 65A alternator provides continuous charging current to dual marine batteries.

Dyno Load Operational Tolerances

Dynamometer evaluation confirms 240BHP continuous output at 4,400 RPM with 300BHP maximum power at 5,000 RPM. The 350 cu in small-block architecture generates 350 ft-lbs of shaft torque at 3,600 RPM. Raw water cooling circuits stabilize engine temperatures between 160°F and 175°F under full-throttle marine operation. Oil pressure reads 40 PSI to 60 PSI at cruising RPM. Main bearing journal runout measures within 0.0006in TIR to prevent crank journal galling during heavy continuous duty cycles.

Maintenance Protocols Hull Selection Criteria

The integrated hydraulic steering actuator keeps steering wheel helm resistance below 4 lbs during hard high-speed turns. Commercial riggers must not install this sterndrive propulsion package in slow displacement tugs or unballasted flat-bottom work barges that require deep reduction diesel gearboxes and large slow-turning propellers.

• Change engine oil and replace the spin-on filter every 100 run hours or 12 months.
• Inspect the flexible raw seawater impeller inside the water pump every 100 operating hours.
• Clean and inspect transom zinc anodes every 6 months to prevent severe electrochemical degradation.

Factory Warranty Manifest Breakdown

Mercury Marine provides 1-Year commercial or 3-Year limited recreational warranty protection. The factory wooden shipping crate contains the 5.7L V8 engine assembly, sterndrive bellhousing, transom plate assembly, drive coupler, power steering actuator, 65A alternator, 12V starter, wiring harness, and official factory maintenance manual documentation.