FNM 42HPEP-350 Complete Sterndrive Marine Diesel Package

Description

Producing 350 BHP at 3,800 RPM paired with a Mercruiser Bravo XR outdrive, the FNM 42HPEP-350 Complete Sterndrive Marine Package equips fast tactical interceptors with massive hole-shot punch. This 4.2L inline-6 system requires strict 2-micron diesel fuel filtration and regular bronze raw water pump impeller servicing to handle high thermal rejection during sustained pursuit runs.

Engine structure unites a parent-bore cast iron block with a 24-Valve cast iron monobloc cylinder head and single overhead camshaft. Electrical systems function on a 12V negative ground loop powered by a 12V 2.8 kW starter motor and a 12V 120A marine alternator. Dry mass reaches 992 lbs across an engine stance measuring 45.3in long by 28.3in wide and 30.9in high. Sump oil volume totals 2.77 US gal.

Key Features of FNM 42HPEP-350

Tactical boat commanders buy FNM 42HPEP-350 complete packages to establish turnkey 350 BHP diesel propulsion on military fast response craft. This commercial workboat diesel engine repower package pairs a heavy-duty Mercruiser Bravo One XR or Bravo Three XR outdrive with hydraulic power trim.

• High-boost variable geometry turbocharger alters exhaust gas flow to produce high low-end boost without turbo lag.
• Oversized seawater intercooler lowers charge air temperatures to sustain 350 BHP peak power output.
• Common rail direct electronic fuel injection operates at 1,800 bar to eliminate soot on boat transoms.
• Mercruiser Bravo XR heavy-duty sterndrive leg features reinforced internal gears built for high continuous torque.
• Monobloc 24-Valve cast iron cylinder head handles severe thermal stress during high-speed emergency response runs.
• Closed-circuit tubular heat exchanger isolates ocean brine from engine blocks to prevent galvanic decay.
• Heavy-duty 12V 120A alternator provides abundant electrical current for tactical communications gear.

Dynamometer Complete Package Test Limits

Dyno cell test runs verify 250 BHP continuous power at 3,200 RPM and 350 BHP intermittent power at 3,800 RPM. Peak shaft torque reaches 495 ft-lbs at 2,400 RPM under maximum turbocharger boost of 2.0 bar. Rail fuel pressure maintains 1,800 bar during sustained wide-open throttle tests. Pre-turbine exhaust gas temperatures peak at 1,180°F under high boost. The tubular heat exchanger stabilizes internal coolant at 185°F. Main journal runout measures 0.0004in TIR, and lube oil gallery pressure settles at 52 PSI across a 25° tilt.

Tactical Sterndrive Operation Maintenance Protocols

Electronic helm throttle levers operate with 1 lb of smooth control action without mechanical friction. Do not drop this high-boost sprint engine into continuous displacement pushboats, coastal trawlers, or slow freight barges running 24-Hour bollard thrust. The sprint profile is engineered for commercial workboat diesel engine repower installations on fast interceptor craft and tactical security boats.

• Drain engine lube oil and replace spin-on oil filters every 250 operating hours with 15W-40 oil.
• Replace primary 2-micron fuel water separator filter elements every 250 operating hours to protect injectors.
• Inspect Bravo XR gear lubricant and replace sacrificial zinc anodes every 150 operating hours in seawater.

Complete Marine Package Warranty Manifest

FNM CMD backs this complete sterndrive package with a 2-Year limited marine manufacturer warranty. The factory shipment includes the 4.2L bobtail engine, Mercruiser Bravo XR outdrive leg, transom assembly, hydraulic trim pump, 12V starter, 12V 120A alternator, digital instrument panel, wiring harness, and official installation manuals.