Yanmar 3JH5E Specifications
| Engine Model: Yanmar 3JH5E |
| Engine Type: 4-stroke inline 3-cylinder naturally aspirated water-cooled diesel |
| Total Displacement: 100 cu.in (1.64 L) |
| Rated Engine Power: 38.5 Hp (28.7 kW) at 3000 rpm |
| Fuel System Type: Direct injection |
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The Yanmar 3JH5E is a 1.6-liter, inline
3-cylinder, naturally aspirated marine diesel engine produced by Yanmar
Marine. Introduced as the successor to the 3JH4E, this engine represents
a significant update featuring increased displacement and improved
environmental compliance, meeting EPA Tier 3, EU RCD, BSO II, and EMC
emission standards.
The Yanmar 3JH5E is a four-stroke, water-cooled diesel engine employing
direct injection combustion technology, a configuration historically
reserved for larger displacement engines but now refined for naturally
aspirated applications through improved injector design and higher fuel
spray pressures. The engine is specifically engineered for mid-sized
sailboats and powerboats, delivering 39 metric horsepower at 3000 rpm
with a dry weight of 173 kg for the base engine. The 3JH5E features
indirect freshwater cooling with a heat exchanger, a gear-driven
seawater pump, and a high-output 125A alternator as standard equipment.
The engine is available with multiple transmission options including the
KM35A mechanical cone clutch gearbox and the SD60 saildrive, providing
flexibility for various vessel configurations from cruising yachts to
power cats up to 13.5 meters. With its undersquare bore/stroke
dimensions and gear-driven pushrod operated valves, the 3JH5E
demonstrates a design philosophy focused on durability and long service
life under marine operating conditions.
The Yanmar 3JH5E is a 4-stroke, inline 3-cylinder diesel engine designed
for marine propulsion in displacement hull vessels. The engine
architecture follows a conventional inline configuration with an evenly
spaced firing interval of 240 deg. The bore and stroke relationship is
slightly undersquare with a stroke of 90 mm and a bore of 88 mm,
promoting torque development at lower engine speeds critical for marine
applications. The engine features direct injection combustion with a
mono-plunger injection pump, providing improved fuel efficiency and
torque output compared to indirect injection designs. The engine is
freshwater-cooled via a heat exchanger and is naturally aspirated.
Engine Type: Inline 3-cylinder, 4-stroke diesel
Displacement: 1.642 L (100 cu.in)
Bore x Stroke: 88 mm x 90 mm (3.46 in x 3.54 in)
Valvetrain: OHV (Overhead Valve), pushrod actuated, 2 per cylinder (6
valves total)
Firing Order: 1-2-3 (for 3-cylinder inline configuration)
Aspiration: Natural
Combustion System: Direct injection, Mono plunger pump
Cooling System: Indirect freshwater cooling with heat exchanger
Direction of Rotation: Counterclockwise viewed from stern
Maximum Output: 28.7 kW (38.5 hp) @ 3000 rpm
Continuous Rating: 26.1 kW (35 hp) @ 2907 rpm
Rated Speed: 3000 rpm
Maximum Continuous Operating Speed: 2900 rpm
Peak Torque: 115 Nm (85 lb-ft) @ 1800 rpm
The cylinder block is constructed from high-strength cast iron,
providing the rigidity required for sustained marine diesel operation.
The block design incorporates parent-bore cylinders machined directly
into the cast iron material, a construction method suitable for the
naturally aspirated power output. The block contains four main bearing
bulkheads to support the forged steel or nodular iron crankshaft.
The crankcase is reinforced around the main bearing areas to manage the
forces generated during direct injection combustion. Cast-in water
jackets surround each cylinder bore, with coolant circulation directed
by the freshwater cooling system and heat exchanger. The block
incorporates mounting points for the heat exchanger, seawater pump, and
transmission adapter. An oil pan constructed from stamped steel forms
the lower crankcase enclosure with a drain plug at its lowest point.
Cylinder Configuration: Inline 3-cylinder
Cylinder Liner Type: Parent-bore (no replaceable liners)
The cylinder head is manufactured from cast iron using an overhead valve
(OHV) design with two valves per cylinder. The valve actuation system
consists of a camshaft located in the cylinder block, mechanical lifters
(tappets), pushrods, and forged steel rocker arms mounted on a rocker
shaft.
The camshaft is gear-driven from the crankshaft timing gear, eliminating
belt replacement intervals and improving reliability under marine duty
cycles. The valves are arranged in an inline configuration. Valve seats
are pressed-in alloy steel rings, and valve guides are replaceable
units. The cylinder head incorporates the direct injection fuel nozzle
bores and the freshwater circulation passages from the heat exchanger.
Valves per Cylinder: 2 (1 intake, 1 exhaust)
Total Valves: 6
Valve Arrangement: Overhead valve (OHV), pushrod actuated
Valve Seat Angle: 45 degrees
Camshaft Drive: Gear train
The fuel system employs direct injection with a mono-plunger injection
pump manufactured by Yanmar under license from Bosch or Zexel. The
injection pump is mounted on the side of the cylinder block and driven
by the engine timing gear train. The direct injection system sprays fuel
directly atop the piston crown, providing more power and torque from
each liter of fuel compared to indirect injection designs.
A mechanical governor integrated into the injection pump housing
maintains engine speed under varying propeller loads. An electric stop
solenoid is fitted for engine shutdown control. A fuel filter with water
separator is mounted on the engine. The injection system is calibrated
to achieve EPA Tier 3 and RCD emission compliance without exhaust
aftertreatment.
Injection System: Direct injection, mono-plunger pump
Injection Pump Type: Inline mechanical, with integral governor
Injection Pressure: Not specified by manufacturer
Fuel Lift Pump: Mechanical diaphragm, gear-driven
Fuel Temperature at Injection Pump Inlet: 40 °C (104 °F)
The lubrication system is a full-pressure, forced-feed, enclosed design.
A gear-type oil pump, mounted on the front of the crankshaft or within
the timing gear cover and driven directly from the crankshaft, draws oil
from the oil pan through a submerged strainer. The pump delivers oil
under pressure to a full-flow spin-on oil filter mounted on the side of
the engine to starboard, positioned to reduce spillage during
replacement. A bypass valve allows oil flow to the bearings if the
filter becomes restricted.
Filtered oil is routed through a main oil gallery machined into the
cylinder block. Cross-drilled passages direct oil to the main bearings,
with drilled crankshaft passages feeding the connecting rod bearings.
Oil is routed upward through the cylinder block and cylinder head to
lubricate the camshaft and valve train components. An oil pressure
relief valve maintains system pressure. A sump oil evacuation pump draws
from the aft end of the oil pan, allowing complete oil removal when the
engine is inclined. The oil pan is constructed from stamped steel.
Oil Type: SAE 30 monograde or SAE 15W-40
Total Oil Capacity: 5.5 L (5.8 US qt)
Oil Pan Capacity: 5.0 L (5.3 US qt)
Oil Filter Type: Spin-on, full-flow, side-mounted
Oil Change Interval: 200 operating hours or annually
The cooling system is an indirect freshwater (coolant) cooling design
with a heat exchanger separating the internal fresh water circuit from
the external raw seawater circuit. A centrifugal fresh water circulating
pump, driven by a V-belt from the crankshaft pulley, circulates coolant
through the engine block and cylinder head. The heated coolant then
passes through a shell-and-tube or plate-type heat exchanger where raw
seawater absorbs the heat before being discharged overboard.
A wax-pellet thermostat regulates coolant flow, maintaining engine
operating temperature between 76-88 °C (169-190 °F). A gear-driven
seawater pump with a rubber impeller is driven from the camshaft. A
belt-driven fan is not fitted as marine engines rely on the heat
exchanger and raw water flow for cooling. A shroud is fitted to protect
the alternator and fresh water circulating pump V-belt from accidental
finger contact.
Coolant Type: Ethylene glycol antifreeze with corrosion inhibitors
Thermostat Opening Temperature: 76-88 °C (169-190 °F)
Heat Exchanger Type: Indirect freshwater cooling
Seawater Pump Type: Gear-driven, rubber impeller
Fresh Water Pump Type: Centrifugal, belt-driven
| Intake and Exhaust Systems |
Intake System: Air enters through a dry-type paper element air cleaner
mounted on the intake manifold. The intake manifold is a cast component
with runners feeding each cylinder. The naturally aspirated design draws
air directly through the air cleaner without turbocharging.
Exhaust System: The exhaust manifold is a single-piece cast iron unit
with three ports merging into a single outlet. The exhaust outlet
diameter is 76 mm (3.0 in). Flexible exhaust gas piping allows routing
out to the transom. The exhaust system includes a water injection elbow
where raw cooling water is mixed with exhaust gases to cool the exhaust
hose.
The engine is equipped with a 12-volt electrical system with a
high-output alternator as standard equipment. The standard alternator
produces 125 amperes at 12 volts. Provision is made for mounting a
second alternator of 80 A or 130 A, or a 24 V 75 A unit, positioned
slightly lower to starboard of the standard high-mounted port-side unit.
A 1.4 kW electric starter motor is fitted for engine starting. The
standard control panel (B panel) includes a key switch, oil pressure
gauge, coolant temperature gauge, tachometer with digital hour meter,
and audible alarms for low oil pressure, high coolant temperature, and
low battery charge.
Starting System: Electric start is standard with engine-mounted starter
motor. Key switch control is standard, with keyless operation optional.
Transmission and Marine Gear Options: KM35A / KM35P: Mechanical cone
clutch gearbox, 7-degree down-angle output, forward ratios 2.33:1,
2.64:1; astern ratio 3.04:1 or 3.16:1 depending on configuration. SD60
Saildrive: Constant mesh gear with mechanical clutch, reduction ratios
2.23:1 or 2.49:1, same ratio ahead and astern. ZF15MA: Mechanical
transmission, reduction ratios 2.14:1 or 2.63:1.
Overall Length (including KM35A gearbox): 770-776 mm (30.3-30.6 in)
Overall Width: 517.6-560 mm (20.4-22.0 in)
Overall Height: 622-623 mm (24.5-24.5 in)
Length (engine only, no gearbox): Not specified
Dry Weight (engine only, without gearbox): 173 kg (381 lb)
Dry Weight (with KM35A gearbox): 186 kg (410 lb)
Dry Weight (with SD60 saildrive): 213 kg (470 lb)
Wet Weight (with all fluids and gearbox): 195-225 kg depending on
configuration
Engine Oil Change Interval: 200 operating hours or annually
Engine Oil Filter Change Interval: Replace with every oil change
Fuel Filter Change Interval: 200-400 operating hours or annually
Valve Clearance Inspection Interval: Every 400-500 operating hours
Valve Clearance: Not specified by manufacturer
Coolant Replacement Interval: 400-500 operating hours or 2 years
Heat Exchanger Zinc Anode Inspection: Every 200 operating hours or 6
months
Seawater Pump Impeller Replacement Interval: 200-400 hours or annually
Air Cleaner Inspection Interval: 200 operating hours
Drive Belt Inspection Interval: Inspect every 200 hours; replace as
needed
Idle Speed (Warm, No Load): 800 ± 50 rpm (marine engine)
Rated Engine Speed (Maximum): 3000 rpm
Maximum Continuous Operating Speed: 2900 rpm
Recommended Cruising Speed Range: 1600-2600 rpm
Cylinder Head Bolts: 88 Nm (65 lb-ft)
Connecting Rod Bolts: 44 Nm (33 lb-ft)
Main Bearing Cap Bolts: 98 Nm (72 lb-ft)
Intake Manifold Bolts: 20-25 Nm (15-18 lb-ft)
Exhaust Manifold Nuts: 20-25 Nm (15-18 lb-ft)
Oil Pan Bolts: 10-12 Nm (7-9 lb-ft)
Water Pump Mounting Bolts: 20-25 Nm (15-18 lb-ft)
Starter Motor Mounting Bolts: 35-40 Nm (26-30 lb-ft)
The Yanmar 3JH5E is engineered specifically for marine propulsion
applications. The engine is suitable for displacement hull vessels where
low to medium speed torque and fuel efficiency are prioritized. The
engine can be installed with minor modifications in place of 3JH3, 4JH2,
and 4JH3 series engines.
Sailboats (Shaft Drive Configuration with KM35A/KM35P/ZF15MA): Monohull
cruising yachts to 11.5 m (38 ft) overall length.
Sailboats (Saildrive Configuration with SD60): Cruising yachts and
sailboats requiring saildrive installation; SD60 provides 2.23:1 or
2.49:1 reduction ratios.
Power Catamarans (Twin Installation with SD60 Saildrive): Capable of
powering catamarans to 13.5 m (44 ft) with twin engine configuration.
Displacement Cruisers: Power cruisers to 7 m (23 ft) overall length.
Auxiliary Propulsion for Larger Sailing Vessels: Suitable as auxiliary
engine for sailboats requiring 35-40 shaft horsepower.
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