Yanmar 4JH45 Auxiliary Inboard Marine Diesel Engine

Description

Heavy-duty parent bore cast iron forms the rigid crankcase block inside the Yanmar 4JH45 Auxiliary Engine. Displacing 2.188L across 4 inline cylinders, this unblown marine diesel produces 45.0 BHP at 3,000 RPM and 40.5 BHP continuous at 2,907 RPM. Common-rail fuel injection demands clean 2-micron fuel pre-filtration to protect precision electronic injector nozzles from abrasive contaminants.

A parent bore cast iron block integrates reinforced main webbings to suppress 4-Cylinder rotational vibration. The single-piece 16-Valve cast iron cylinder head contains dual overhead camshafts with direct valve actuation. Electrical architecture features a 12V 2-pole isolated earth circuit with NMEA 2000 output, a 1.4 kW starter, and a 12V 125A alternator. Dimensions span 34.0in long, 22.2in wide, and 25.5in high, weighing 516 lbs with gearbox. Oil pan capacity holds 1.32 US gal.

Key Features of Yanmar 4JH45

Blue-water cruising sailors buy Yanmar 4JH45 auxiliary marine diesel engines to repower 36ft to 45ft sailing ketches and displacement cruisers. Marine service yards choose this package for commercial workboat diesel engine repower installations in harbor launches.

• Bosch common-rail direct fuel injection optimizes atomization to eliminate transom soot and smoke
• Atmospheric induction runner tuning provides instant throttle response without turbocharger maintenance complexity
• Tubular freshwater heat exchangers protect internal cast iron water jackets from corrosive sea brine
• High-output 12V 125A marine alternators replenish large deep-cycle house battery banks during harbor transit
• NMEA 2000 CAN-bus data networks stream engine parameters straight to modern helm multifunction displays
• SAE 5 flywheel housings connect directly to Yanmar KM35P gearboxes, ZF 25, or SD60 saildrives
• Parent bore cast iron cylinders maintain thermal stability under continuous heavy ocean motoring duty

Bench Dynamometer Load Test Output

Dynamometer test runs prove 45.0 BHP peak crankshaft output at 3,000 RPM and 40.5 BHP continuous power at 2,907 RPM. Electronic common-rail fuel pressure maintains 1,600 bar across high-load test cycles. Freshwater heat exchangers hold core coolant temperatures steady at 178°F under continuous thermal load. Engine oil pressure maintains 50 PSI across operational engine speeds. Shaftline installation permits up to 15° static inclination angles. Crankshaft journal runout remains below 0.0004in TIR to protect bearings against deflection fatigue. Exhaust temperatures stay below 1,050°F during full power runs.

Field Operation Maintenance Service Rules

Mechanical control linkages or electronic CAN-bus interfaces provide smooth throttle modulation with under 2 lbs of lever resistance. Do not install this 45.0 BHP auxiliary engine in heavy commercial displacement tugs, fast planing skiffs, or vessels lacking secondary 2-micron fuel water separator filtration. Operators must change fuel filters on schedule to safeguard common-rail components.

• Drain engine oil and change spin-on oil filter cartridges every 150 operating hours
• Inspect raw water pump impellers and check heat exchanger zinc anodes every 150 hours
• Replace the primary 2-micron fuel water separator filter cartridge every 250 engine hours

Factory Warranty Shipment Parts Manifest

Yanmar Marine provides a 2-Year limited warranty backed by 3-Year major component structural coverage. The shipment crate contains the 4JH45 diesel engine core, KM35P marine gearbox, high-output 12V 125A alternator, 1.4 kW starter motor, flexible vibration mounts, B20 instrument panel, wiring harness, and factory technical manuals.