Yanmar 4JH2 UTE Specifications
| Engine Model: Yanmar 4JH2 UTE |
| Engine Type: 4-stroke inline 4-cylinder turbocharged water-cooled diesel |
| Total Displacement: 110.9 cu.in (1.82 L) |
| Rated Engine Power: 100 Hp (73.6 kW) at 3600 rpm |
| Fuel System Type: Indirect injection |
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The Yanmar 4JH2-UTE is a high-output,
4-cylinder, turbocharged and intercooled diesel engine belonging to the
JH series. As the most powerful variant in the 4JH2 line, it was
specifically engineered for larger sailboats and light motor cruisers
where a high power-to-weight ratio and compact installation dimensions
are required. The engine utilizes indirect injection with a swirl
chamber combustion system, a configuration that provides smooth
operation and reduced noise while permitting a lightweight construction.
The UTE designation indicates the presence of both a turbocharger and a
seawater-cooled intercooler, a combination that elevates power output to
100 hp from a displacement of only 1.8 liters. Production of this engine
began in 1991, and it remains a common powerplant in cruising yachts
from manufacturers such as Beneteau and Hylas.
Engine Type: Vertical, 4-cycle, water-cooled diesel
Number of Cylinders: 4
Bore x Stroke: 82 mm x 86 mm (3.23 in x 3.39 in)
Displacement: 1.817 L (110.9 cu.in)
Combustion System: Indirect injection (swirl chamber)
Compression Ratio: 23:1
Aspiration: Turbocharged with seawater-cooled intercooler
Maximum Output (Crankshaft): 100 hp (73.6 kW) at 3600 rpm
Continuous Rating: 84 hp (61.8 kW) at 3500 rpm
Maximum Torque: 240 Nm (177 lb-ft) at 2400 rpm
Cruising RPM Range: 2900 to 3100 rpm
Low Idle Speed: 700 to 800 rpm
Direction of Rotation: Counter-clockwise (viewed from flywheel side)
Starting System: Electric start, 12V with 1.8 kW starter
Alternator: 12V, 55A (standard) or 80A (optional)
Flywheel Housing Pattern: SAE-4
0The cylinder block is a single-piece cast iron unit with an open-deck
design. This configuration permits effective coolant circulation around
each cylinder bore, a critical requirement for an engine operating under
sustained turbocharged loads. The block houses a forged steel crankshaft
supported by five main bearings, a design that provides the structural
rigidity necessary to withstand the increased mechanical loads from
combustion pressures exceeding 130 bar.
The block incorporates an integrated oil gallery that routes pressurized
lubricant to the crankshaft bearings, connecting rod bearings, and the
piston cooling jets. The oil pan is a pressed steel sump with a baffled
design to maintain oil supply during vessel heeling and pitching
motions. The gear housing and flywheel housing are separate castings
bolted to the front and rear of the block respectively.
The cylinder head is a single-piece cast iron unit with a cross-flow
design. The valve arrangement uses four valves per cylinder, two intake
and two exhaust, actuated by a pushrod system. Intake valve diameter is
32 mm (1.26 in). Exhaust valve diameter is 28 mm (1.10 in). The
valvetrain includes a camshaft located within the cylinder block,
driving pushrods that actuate rocker arms (ratio 1.3:1).
Valve rotators are not equipped; manual adjustment of valve clearance is
required. The combustion chamber is located within the cylinder head,
featuring a spherical swirl chamber design optimized for complete
combustion and reduced exhaust emissions. The injector nozzle is
positioned to spray fuel into this pre-chamber, initiating combustion
before flame propagation into the main chamber.
The cylinder head gasket is a steel laminate design with a viton rubber
sealing bead around each cylinder bore and each oil passage. The valve
clearance specification when cold is 0.2 mm (0.008 in) for both intake
and exhaust valves.
The fuel system is a mechanical indirect injection system using an
in-line injection pump manufactured by Yanmar. The injection pump is
mounted on the side of the cylinder block and driven by a gear from the
camshaft. The pump contains four individual plunger and barrel
assemblies, one per cylinder, actuated by a camshaft within the pump
body. A mechanical governor, integrated into the injection pump housing,
controls engine speed by regulating the fuel rack position. The governor
includes idle and maximum speed spring sets.
A delivery valve and damping valve mechanism in the injection pump
prevents delayed injection and maintains residual pressure in the
injection pipes for the next injection event. Injection nozzles are of
the multi-hole type, installed in the cylinder head and positioned to
inject fuel into the swirl chamber. Nozzle opening pressure is set to
20.0 to 20.6 MPa (2,900 to 2,986 psi). A feed pump mounted on the
injection pump body draws fuel from the tank through a water separator
and a replaceable cartridge-type fuel filter. The injection timing is
electronically controlled on later variants.
The lubrication system is a forced-feed, full-flow pressurized system
using a trochoid-type oil pump. The oil pump is mounted externally on
the front of the cylinder block and driven directly by the crankshaft
gear. Oil is drawn from a pressed steel oil pan through a mesh suction
strainer positioned 15 mm above the pan floor.
The system includes a water-cooled oil cooler, mounted on the side of
the cylinder block, which uses seawater from the raw water circuit to
stabilize oil temperature under sustained high-load operation. The oil
filter is a spin-on, full-flow type with a cellulose media rated for
25-micron nominal filtration. An integral bypass valve opens at a
differential pressure of 1.0 bar (15 psi) to maintain flow during cold
starts.
Piston cooling is achieved through four nozzle jets, each calibrated to
deliver oil to the underside of each piston crown. The engine oil
capacity including the filter is 6.5 L (6.9 qt). Operating oil pressure
at rated speed is 3.0 to 4.5 bar (44 to 65 psi). Minimum oil pressure at
low idle, at operating temperature, is 0.8 bar (12 psi).
The cooling system is an indirect freshwater (closed-loop) system with a
seawater heat exchanger. Freshwater circulation is driven by a
belt-driven centrifugal pump. The thermostat is a wax-pellet,
single-stage design with a rated opening temperature of 71°C (160°F) and
a fully open position at 85°C (185°F). Coolant flow is directed first to
the cylinder block, then upward through the cylinder head, and finally
through the external oil cooler and heat exchanger before returning to
the pump.
A secondary seawater circuit, driven by a rubber-impeller raw water
pump, passes through a charge air cooler (intercooler) and then through
the heat exchanger to remove heat from the freshwater circuit. The
exhaust system includes a water-cooled mixing elbow where seawater is
injected into the exhaust stream to cool exhaust gases before discharge.
The engine and heat exchanger coolant capacity is 8.5 L (9.0 qt). A
coolant pressure cap rated at 0.5 bar (7 psi) is fitted to the expansion
tank.
Timing Drive: A front-mounted gear train drives the camshaft, injection
pump, and water pump. The camshaft gear is driven by an idler gear from
the crankshaft gear. All gears are helical-cut steel for quiet
operation. No timing belts are used.
Turbocharger: The turbocharger is a fixed-geometry, water-cooled unit.
The bearing housing is cooled by coolant from the freshwater circuit.
Maximum boost pressure at rated power is 1.2 bar (17 psi). The
turbocharger is oil-lubricated from the engine's main oil gallery.
Intercooler: A seawater-cooled charge air cooler reduces intake air
temperature after the turbocharger, increasing air density and
combustion efficiency.
Crankcase Ventilation: An open crankcase ventilation system routes
blow-by gases through a labyrinth-type oil separator. The separated oil
drains back to the oil pan. Gases vent to the atmosphere via a draft
tube.
Electrical System: A 12-volt system is standard. The wiring harness
includes sensors for oil pressure, coolant temperature, and tachometer.
An instrument panel with warning lamps and gauges is provided with the
engine. A stop solenoid provides electric engine shutdown.
Dry Weight (without gearbox): 239 to 246 kg (527 to 542 lb)
Length (front to rear): 906 mm (35.7 in)
Width (extreme, including turbocharger and heat exchanger): 561 mm (22.1
in)
Height (from oil pan rail to rocker cover top): 635 mm (25.0 in)
Engine Oil Capacity (with filter): 6.5 L (6.9 qt)
Recommended Oil Grade: SAE 15W-40 or SAE 10W-30 (API CF or higher)
Coolant Capacity (engine and heat exchanger): 8.5 L (9.0 qt)
Seawater Pump Impeller Replacement: 200 hours or 1 year
Oil Change Interval: 200 hours or annually, whichever occurs first
Oil Filter Replacement: Replace with every oil change
Fuel Filter Replacement: 200 hours or annually
Fuel Injector Nozzle Opening Pressure: 20.0 to 20.6 MPa (2,900 to 2,986
psi)
Injection Timing: Electronically controlled on later variants;
mechanical timing 15° BTDC
Valve Clearance (Cold): Intake: 0.2 mm (0.008 in); Exhaust: 0.2 mm
(0.008 in)
Valve Adjustment Interval: 500 hours
Compression Pressure: 2.9 to 3.2 MPa (29 to 32 kg/cm2) at 250 rpm
Cylinder Head Bolts, Stage 1: 30 Nm (22 lb-ft)
Cylinder Head Bolts, Stage 2: 60 Nm (44 lb-ft)
Connecting Rod Cap Bolts (M9 x 1.0): 45 Nm (33 lb-ft)
Main Bearing Cap Bolts (M12 x 1.5): 80 Nm (59 lb-ft)
Flywheel Bolts (M10 x 1.25): 55 Nm (41 lb-ft)
Flywheel Housing Bolts (M10 x 1.5): 45 Nm (33 lb-ft)
Rocker Shaft Pedestal Nuts: 25 Nm (18 lb-ft)
Injector Nozzle Holder Nuts: 40 Nm (30 lb-ft)
Injection Pump Flange Nuts: 20 Nm (15 lb-ft)
Oil Pan Drain Plug (M14 x 1.5): 35 Nm (26 lb-ft)
Heat Exchanger End Cover Bolts: 15 Nm (11 lb-ft)
Sailboats: Beneteau Farr 50 (75 hp rating); Hylas 54 (100 hp rating);
Peterson Schooner (75 hp rating); various cruising yachts from 40 to 55
ft length overall.
Motor Cruisers: Seaward 23 (100 hp rating, max speed 14 knots);
semi-displacement and planing hulls in the 25 to 35 ft range.
Commercial Vessels: Small workboats; pilot boats; water taxis.
Industrial: Marine auxiliary generator drives; hydraulic power units.
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