Yanmar 4JH5E Specifications
| Engine Model: Yanmar 4JH5E |
| Engine Type: 4-stroke inline 4-cylinder naturally aspirated water-cooled diesel |
| Total Displacement: 134 cu.in (2.19 L) |
| Rated Engine Power: 54 Hp (39.6 kW) at 3000 rpm |
| Fuel System Type: Direct injection |
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The Yanmar 4JH5E is a 2.2-liter, naturally
aspirated, inline four-cylinder marine diesel engine manufactured by
Yanmar. This powerplant belongs to the JH series, a platform engineered
for recreational sailboats, motor yachts, and light-duty commercial
vessels operating in the 39 to 125 horsepower class. The 4JH5E serves as
the direct injection successor to the 4JH4E, offering increased
displacement and improved fuel efficiency while maintaining mechanical
simplicity with a conventional in-line fuel injection pump rather than a
common rail system.
The engine operates on a four-stroke, compression-ignition cycle with a
vertical, water-cooled inline configuration. The direct injection
combustion system, featuring a mono plunger pump, delivers fuel directly
into a recessed bowl machined into the piston crown, improving thermal
efficiency and reducing fuel consumption compared to indirect injection
designs. Yanmar engineered the 4JH5E with a fresh water cooling system
with a heat exchanger, isolating the engine block from corrosive
seawater while maintaining stable operating temperatures.
The engine carries a counterclockwise crankshaft rotation when viewed
from the flywheel end. The 4JH5E is found in vessels from Universal
Orlando Resort water taxies, where units have logged more than 13,000
hours of service, to cruising sailboats and displacement motor yachts
requiring a reliable 54 horsepower auxiliary power source.
The Yanmar 4JH5E is a four-stroke, compression-ignition, inline
four-cylinder diesel engine with vertical cylinder arrangement. The
induction system is naturally aspirated without turbocharging equipment.
Total displacement measures 2.19 liters, equivalent to 134 cubic inches.
The bore dimension is 88 mm (3.46 in), and the stroke dimension is 90 mm
(3.54 in). Maximum power output reaches 39.6 kW, equivalent to 54 hp, at
an engine speed of 3,000 rpm.
Continuous power rating is 36.0 kW, equivalent to 48.3 hp, at an engine
speed of 2,907 rpm. Maximum torque is 142 Nm, equivalent to 105 lb-ft,
at an engine speed of 1,800 to 2,000 rpm. The cruising rpm range is
2,400 to 2,700 rpm. The combustion system is direct injection with a
mono plunger pump. Fuel injection timing is 14 degrees before top dead
center (BTDC). Fuel injection pressure is 19.6 MPa to 20.6 MPa,
equivalent to 200 to 210 kg/cm2.
The cylinder block is constructed from cast iron, providing rigidity,
vibration damping, and wear resistance required for prolonged marine
service. The block is an inline four-cylinder design with integral
cylinder bores. A five-main-bearing crankshaft support structure is
employed, with four connecting rod journals positioned between five main
bearings. This arrangement provides the crankshaft support necessary for
the engine's 54 hp output and continuous duty cycle capability.
The deep-skirt block design extends below the crankshaft centerline,
enhancing structural rigidity under sustained load. The water jacket
surrounds the entirety of the cylinder bores to maximize heat transfer
away from the combustion zone. The cylinder block includes the gear
housing at the front, containing the gear train that drives the
camshaft, injection pump, and oil pump.
The cylinder head is a separate cast-iron component bolted to the top of
the cylinder block using a single-piece head gasket. The cylinder head
contains two valves per cylinder, one intake and one exhaust, for a
total of eight valves. The overhead valve (OHV) configuration uses
pushrods actuated by the camshaft located within the cylinder block.
The combustion chamber is formed as a recessed bowl machined directly
into the piston crown, a defining feature of the direct injection
system. Valve lash adjustment is performed via set screws on the rocker
arms. Cold valve clearance specification for both intake and exhaust
valves is 0.20 mm (0.008 in). The cylinder head assembly includes valve
seats, valve guides, rocker arm shaft, rocker arms, and valve springs.
The fuel system employs a mechanical direct injection design with a mono
plunger pump. The injection pump is a distributor-type or in-line pump
depending on the specific variant. The pump is mounted on the side of
the cylinder block and driven by a gear train from the camshaft. A
mechanical centrifugal governor controls engine speed, sensing engine
rpm and adjusting fuel delivery to maintain the selected speed under
varying loads. A fuel feed pump mounted on the injection pump housing
draws fuel from the tank through a primary filter and water separator.
The injection pump pressurizes fuel to 200 to 210 kg/cm2 (2,844 to 2,986
psi) and delivers it to individual injection lines. These steel lines
carry high-pressure fuel to the injection nozzles mounted in the
cylinder head. Each nozzle directs fuel directly into the piston bowl
recess, where the fuel mixes with compressed, heated air and
auto-ignites. An electric stop solenoid provides engine stopping from
the helm station. An optional air heater (glow plug) assists starting in
cold weather.
The lubrication system is a forced lubrication design with a trochoid
pump and an oil cooler. The oil pump is driven directly by a gear on the
crankshaft. A suction pipe extends from the pump into the oil sump,
drawing oil through a wire-mesh strainer. After pressurization, oil
passes through a full-flow oil filter mounted externally on the cylinder
block. From the filter, oil travels through internal drillings to reach
the five main bearings.
Drilled passages within the crankshaft direct oil from the main bearings
to the connecting rod bearings. Excess oil is directed upward through
vertical passages to lubricate the valve train. The system capacity,
including the oil filter, is 5.0 liters (5.3 US qt). Operating oil
pressure at rated engine speed should register 340 kPa to 440 kPa (49
psi to 64 psi), equivalent to 3.5 to 4.5 kg/cm2. Recommended oil
viscosity is SAE 15W-40 or SAE 10W-30 with API service classification CF
or higher.
The cooling system is an indirect fresh water cooling system with a heat
exchanger. This marine-specific design uses two separate water circuits.
The primary circuit contains fresh water mixed with coolant additive,
circulating through the engine block, cylinder head, and the tube side
of the heat exchanger. A centrifugal fresh water pump driven by the
engine circulates the fresh water. The secondary circuit draws raw water
(seawater or fresh water) through a sea strainer.
A flexible-impeller raw water pump pumps the raw water through the shell
side of the heat exchanger, where it absorbs heat from the engine
coolant before being discharged overboard through the exhaust mixing
elbow. This system isolates the engine's internal passages from
corrosive seawater. A wax-type thermostat regulates the fresh water
temperature. The engine coolant capacity, including the heat exchanger,
is 6.0 liters (6.3 US qt). A separate expansion tank for the fresh water
cooling system is included in the standard engine package.
Electrical System: The electrical system is 12-volt with negative
ground. A starter motor rated at 1.4 kW engages with the flywheel ring
gear. A belt-driven alternator is available in 80 ampere or 125 ampere
ratings depending on specification. A secondary alternator option
provides 12V-130A or 24V-75A output with a smart regulator for vessels
with high electrical loads.
Air Intake System: Air enters through a dry-type air cleaner with a
paper filter element. An optional air heater (glow plug) is available
for cold starting assistance.
Exhaust System: Exhaust gases exit each cylinder into the exhaust
manifold, then pass through a water-cooled mixing elbow where raw water
is injected to cool the exhaust gases before entering the exhaust hose.
The standard mixing elbow is an L-type, with a high-riser mixing elbow
available as an option for vessels requiring greater exhaust lift.
Transmission Options: The engine is available with KM35A mechanical cone
clutch marine gear, KMH series hydraulic disc drive transmissions, or
SD60 sail drive unit depending on the vessel configuration. Forward
reduction ratios range from 2.23:1 to 2.61:1 depending on the
transmission model, with reverse ratios of 3.16:1 for mechanical cone
clutch units.
The complete engine assembly, including the injection pump, heat
exchanger, alternator, starter, and flywheel housing, has an overall
length of 871 mm (34.3 in), a width of 560 mm (22.0 in), and a height of
623 mm (24.5 in). The dry weight, excluding fluids but including all
standard engine-mounted accessories and the flywheel housing, is 201 kg
(443 lb).
Service intervals for the 4JH5E are based on operating hours. Engine oil
and filter should be changed every 250 hours under normal conditions.
For a new engine or after major overhaul, change the oil after the
initial 50 hours of operation. Oil viscosity selection follows SAE
15W-40, 10W-30, or 5W-30 depending on ambient temperature, with API
service classification CF or higher.
The fuel filter requires replacement every 500 hours. The air cleaner
element requires cleaning every 250 hours and replacement every 1,000
hours. Valve lash adjustment is required every 500 hours. The cooling
system requires testing of coolant freeze point and corrosion inhibitor
level every 250 hours. Complete coolant replacement occurs every 1,000
hours or one year.
The raw water pump impeller requires inspection every 250 hours and
replacement every 500 hours. Fuel injection timing should be checked
every 1,000 hours. The fuel injectors require testing and recalibration
every 1,000 hours. The engine meets EPA Tier 2 and RCD emission
standards. The maximum continuous operating speed is 3,600 rpm, with
maximum throttle operation limited to less than 5 percent of total
engine time.
Cylinder head bolts receive a torque of 83 Nm (61 lb-ft), equivalent to
8.5 kgm. A crosswise tightening sequence from the center outward must be
followed. Connecting rod cap nuts are torqued to 54 Nm (40 lb-ft),
equivalent to 5.5 kgm. Main bearing cap bolts receive a torque of 113 Nm
(83 lb-ft), equivalent to 11.5 kgm. The crankshaft V-pulley bolt is
torqued to 123 Nm (90 lb-ft), equivalent to 12.5 kgm.
The flywheel bolts are torqued to 78 Nm (58 lb-ft), equivalent to 8.0
kgm. The damper disk bolts receive 25 Nm (18 lb-ft), equivalent to 2.6
kgm. The rocker arm shaft bracket nuts are secured to 25 Nm (18 lb-ft).
Intake manifold bolts receive 20 Nm (15 lb-ft). Exhaust manifold nuts
are torqued to 25 Nm (18 lb-ft). The injection pump mounting nuts
receive 20 Nm (15 lb-ft). The injector hold-down nuts are torqued to 25
Nm (18 lb-ft).
The oil filter canister requires tightening to 15 Nm (11 lb-ft) or
three-quarters of a turn after gasket contact. The oil drain plug is
torqued to 40 Nm (30 lb-ft). The fresh water pump mounting bolts receive
15 Nm (11 lb-ft). The raw water pump mounting bolts receive 12 Nm (9
lb-ft). The starter motor mounting bolts are torqued to 35 Nm (26
lb-ft). The alternator mounting bolts receive 25 Nm (18 lb-ft).
The Yanmar 4JH5E engine powers a range of marine vessels requiring
auxiliary or primary propulsion. Primary applications include sailboats
from 11 meters (36 ft) to 15 meters (49 ft) in length, where the engine
serves as auxiliary power for maneuvering and motoring during calm
conditions. Motor yacht applications include displacement and
semi-displacement hulls up to 12 meters (40 ft) requiring a 54 hp power
plant.
Commercial applications include water taxis, as demonstrated by the
Universal Orlando Resort fleet where multiple 4JH5E engines have
accumulated over 12,000 operating hours each. The engine is also found
in small fishing vessels, harbor launches, and utility craft.
The 4JH5E can be installed with minimal modifications in place of older
3JH3, 4JH2, and 4JH3 series engines. The engine is distinct from the
turbocharged Yanmar 4JH4-TE and 4JH4-HTE (74 hp to 110 hp) and the
larger Yanmar 4JH5A-E (75 hp) within the same JH series family. A sail
drive variant is available with the SD60 unit, offering 2.23:1 and
2.49:1 reduction ratios.
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