Yanmar 4LH HTE Specifications
| Engine Model: Yanmar 4LH HTE |
| Engine Type: 4-stroke inline 4-cylinder turbocharged water-cooled diesel |
| Total Displacement: 210.9 cu.in (3.45 L) |
| Rated Engine Power: 140 Hp (103 kW) at 3300 rpm |
| Fuel System Type: Direct injection |
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The Yanmar 4LH-HTE is a 4-stroke, vertical,
water-cooled marine diesel engine produced by Yanmar Marine. Positioned
as a mid-range variant within the 4LH series, this engine represents a
direct-injection powerplant equipped with both a turbocharger and an
intercooler to optimize performance and efficiency for planing and
semi-displacement vessels.
The Yanmar 4LH-HTE features a 4-cylinder inline configuration with a
displacement of 3.455 liters, producing 140 horsepower at 3300 rpm. The
engine incorporates a fresh water cooling system via a heat exchanger,
utilizing a centrifugal fresh water pump and a rubber impeller seawater
pump. The water-cooled exhaust manifold and mixing elbow provide reduced
engine room temperatures and improved component durability.
The Yanmar 4LH-HTE shares a common cylinder block and many internal
components with other 4LH series engines, including the TE, DTE, and STE
variants. This engine is available in multiple reduction gear
configurations, including the KMH4A and KMH5A transmissions, with a
standard KMH5A 2.63 ratio option frequently selected. The robust
construction and forced lubrication system make the 4LH-HTE suitable for
continuous marine duty cycles, from fast cruisers to light commercial
applications.
The Yanmar 4LH-HTE is a 4-stroke, inline 4-cylinder diesel engine
designed for marine propulsion. The engine architecture follows a
conventional inline configuration with an evenly spaced firing interval
of 180 degrees. The bore and stroke relationship is oversquare with a
stroke of 110 mm and a bore of 100 mm, promoting torque development at
the 3300 rpm rated speed required for planing hull applications.
The engine features direct injection combustion with a rotary injection
pump providing improved fuel atomization and combustion efficiency. The
engine is turbocharged and intercooled, with the intercooler reducing
intake air temperature before entry to the suction manifold. The
water-cooled turbocharger design improves durability under sustained
high-load operation.
Engine Type: Inline 4-cylinder, 4-stroke diesel
Displacement: 3.455 L (3,455 cc / 210.9 cu.in)
Bore x Stroke: 100 mm x 110 mm (3.94 in x 4.33 in)
Compression Ratio: 18.3:1
Valvetrain: OHV, pushrod actuated, 2 valves per cylinder (8 valves
total)
Firing Order: 1-3-4-2 (for 4-cylinder inline configuration)
Aspiration: Turbocharged with intercooler
Combustion System: Direct injection
Cooling System: Fresh water cooling with heat exchanger
Rotation Direction: Counterclockwise viewed from stern
Maximum Power: 140 hp (103 kW) @ 3,300 rpm
Rated Speed: 3,300 rpm
Maximum Continuous Speed: 3,000-3,100 rpm (recommended)
Peak Torque: 415 Nm (306 lb-ft) @ 2,000-2,200 rpm
Torque at 3,300 rpm: 298 Nm (220 lb-ft)
The cylinder block is constructed from high-strength cast iron,
providing the rigidity required for sustained marine diesel operation
with turbocharging. The block incorporates parent-bore cylinders
machined directly into the cast iron material, a construction method
suitable for the power output. The block contains five main bearing
bulkheads to support the forged steel 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 fresh water cooling system and heat
exchanger. The cylinder block shares the same basic casting as the
4LHA-HTE and other LH series engines. The block incorporates mounting
points for the turbocharger, intercooler, 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 4-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
pressed into the head casting. The cylinder head incorporates the direct
injection fuel nozzle bores and the fresh water circulation passages
from the heat exchanger.
Valves per Cylinder: 2 (1 intake, 1 exhaust)
Total Valves: 8
Valve Arrangement: Overhead valve (OHV), pushrod actuated
Intake Valve Clearance (Cold): 0.15-0.25 mm (0.006-0.010 in)
Exhaust Valve Clearance (Cold): 0.25-0.35 mm (0.010-0.014 in)
Valve Seat Angle: 45 degrees
Camshaft Drive: Gear train
The fuel system employs direct injection with a rotary injection pump.
The injection pump is mounted on the side of the cylinder block and
driven by the engine timing gear train. The system includes a mechanical
or electronic governor, with the 4LH-HTE utilizing mechanical governor
controls for marine applications. An electric stop solenoid is fitted
for engine shutdown control. A fuel strainer (filter) with water
separator is mounted on the engine. The injection system is calibrated
to meet Yanmar efficiency standards.
Injection Pump: Rotary type, gear-driven from engine timing train
Injection Pump Part Number: 119171-67200 (with magnetic solenoid)
Injection Valve (Nozzle): 4-hole type, direct injection into combustion
chamber
Fuel Injection Pipe: High-pressure steel lines from pump to each
injector
Fuel Strainer: Replaceable element type with water separation bowl
Fuel Type: Diesel (density at 15 °C = 0.835-0.855 g/cc)
Injection System: Direct injection, rotary pump
Injection Pressure: 22.6 MPa (3,278 psi) @ nozzle
Injection Timing: 12-14 degrees BTDC @ rated speed
Governor Type: Mechanical, centrifugal
Fuel Lift Pump: Mechanical diaphragm, gear-driven from camshaft
The lubrication system is a full-pressure, forced-feed, enclosed design.
A gear-type oil pump, mounted 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 cylinder block. 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 five 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. An oil cooler, mounted on the engine, uses
raw seawater to cool the engine oil before it returns to the sump. An
automatic bilge pump can be installed as optional equipment for engine
room maintenance.
Oil Type: SAE 30 monograde or SAE 15W-40 (API CF or higher)
Total Oil Capacity (including filter): 10.0 L (10.6 US qt)
Oil Pan Capacity: 8.5 L (9.0 US qt)
Oil Filter Type: Spin-on, full-flow, side-mounted
Oil Pressure (Operating, warm): 392-588 kPa (57-85 psi) @ 2,000 rpm
Oil Pressure (Idle, warm, minimum): 98 kPa (14 psi)
Oil Change Interval: 150 operating hours or annually
Oil Cooler Type: Shell-and-tube, raw water-cooled
The cooling system is an indirect fresh water (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,
complete with a raw water strainer for debris protection. A mixing elbow
combines raw water with exhaust gases to cool the exhaust hose. The
turbocharger is also fresh water-cooled on the 4LH-HTE variant.
Coolant Type: Ethylene glycol antifreeze with corrosion inhibitors
Total Cooling Capacity (engine and heat exchanger): 7.0 L (7.4 US qt)
Thermostat Opening Temperature: 76-82 °C (169-180 °F)
Thermostat Full Open Temperature: 90 °C (194 °F)
Heat Exchanger Type: Shell-and-tube, fresh water/raw water
Seawater Pump Type: Gear-driven, rubber impeller (maintenance part)
Fresh Water Pump Type: Centrifugal, belt-driven
Radiator Cap Pressure (heat exchanger): 98 kPa (1.0 kg/cm2)
| Intake and Exhaust Systems |
Intake System: Air enters through a dry-type paper element air cleaner
mounted on the turbocharger intake. The turbocharger compresses incoming
air, which then passes through the intercooler. The intercooler reduces
intake air temperature from approximately 150 °C (302 °F) after
turbocharging down to 50-60 °C (122-140 °F) before entering the suction
manifold. The intake manifold is a cast component with runners feeding
each cylinder.
Exhaust System: The exhaust manifold is a single-piece cast iron,
water-cooled unit with 4 ports merging into a single outlet for the
turbocharger. The water-cooled design reduces engine room surface
temperatures and improves safety. The mixing elbow combines raw cooling
water with exhaust gases, reducing exhaust hose temperatures. Exhaust
pipe diameter is specified at 76 mm (3.0 in) for standard installations.
The engine is equipped with a 12-volt electrical system with a standard
alternator. The standard alternator produces 60 amperes at 12 volts. An
optional 80-ampere alternator is available for vessels with higher
electrical demands. The starter motor is a 12V, 2.0 kW unit.
The standard instrument panel (B-TYPE) 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. Optional panel configurations
include C-TYPE, D-TYPE, and E-TYPE with additional monitoring
capabilities.
Turbocharger System: The 4LH-HTE utilizes a Mitsubishi TD04HL-15T
water-cooled turbocharger mounted directly to the exhaust manifold. The
water-cooled bearing housing extends turbocharger life under marine
operating conditions. Maximum boost pressure is 0.12 MPa (1.2 bar / 17.4
psi) at rated speed.
Starting System: Electric start is standard with engine-mounted starter
motor and 12V battery requirement (min. 100 Ah capacity). A key switch
control is standard, with a single lever control optional for integrated
throttle and shift operation.
Transmission Options (KMH Series): KMH4A: Mechanical cone clutch,
reduction ratios 2.21:1 and 2.61:1. KMH5A: Mechanical cone clutch,
reduction ratios 2.00:1, 2.47:1, and 2.63:1 (2.63:1 is the most common
selection).
Overall Length (excluding gearbox): 1,058 mm (41.7 in)
Overall Width (maximum): 589-600 mm (23.2-23.6 in)
Overall Height (maximum): 737-820 mm (29.0-32.3 in)
Length (including KMH5A gearbox): 1,220 mm (48.0 in)
Dry Weight (engine only, without gearbox): 400-412 kg (882-908 lb)
Dry Weight (with KMH5A gearbox): 450 kg (992 lb)
Wet Weight (with all fluids and gearbox): 475 kg (1,047 lb)
Engine Oil Change Interval: 150 operating hours or annually
Engine Oil Filter Change Interval: Replace with every oil change
Fuel Filter (Strainer) Change Interval: 200-400 operating hours or
annually
Fuel Filter Element Replacement: Replace if water indicator shows
contamination
Valve Clearance Inspection Interval: Every 400-500 hours following
engine break-in
Intake Valve Clearance (Cold): 0.15-0.25 mm (0.006-0.010 in)
Exhaust Valve Clearance (Cold): 0.25-0.35 mm (0.010-0.014 in)
Valve Clearance Adjustment Interval: 800 operating hours (or as
required)
Coolant Replacement Interval: 500 operating hours or 2 years
Heat Exchanger Zinc Anode Inspection: Every 150 operating hours or 6
months
Seawater Pump Impeller Replacement Interval: 200-300 hours or annually
Air Cleaner Inspection Interval: 150 operating hours
Drive Belt Inspection Interval: Inspect every 200 hours; replace as
needed
Injection Timing Check Interval: 800 operating hours
Injection Nozzle Inspection Interval: 1,000 operating hours
Turbocharger Inspection Interval: 2,000 operating hours
Idle Speed (Warm, No Load, in gear): 800 ± 50 rpm
Idle Speed (Warm, No Load, out of gear): 700 ± 50 rpm
Rated Engine Speed (Maximum): 3,300 rpm
Maximum Continuous Operating Speed: 3,100 rpm
Recommended Cruising Speed Range: 2,300-3,100 rpm
Cylinder Head Bolts (Step 1): 30 Nm (22 lb-ft)
Cylinder Head Bolts (Step 2): 90 Nm (66 lb-ft)
Cylinder Head Bolts (Step 3): 135-145 Nm (99-107 lb-ft)
Connecting Rod Bolts: 50 Nm (37 lb-ft)
Main Bearing Cap Bolts: 54 Nm (40 lb-ft)
Crankshaft Pulley Bolt: 235-255 Nm (173-188 lb-ft)
Flywheel Bolts: 64-68 Nm (47-50 lb-ft)
Camshaft Timing Gear Bolt: 98-118 Nm (72-87 lb-ft)
Intake Manifold Bolts: 20-25 Nm (15-18 lb-ft)
Exhaust Manifold Nuts: 30-35 Nm (22-26 lb-ft)
Injector Clamp Bolts: 18-22 Nm (13-16 lb-ft)
Injection Pump Mounting Nuts: 20-25 Nm (15-18 lb-ft)
Rocker Shaft Bracket Bolts: 25-30 Nm (18-22 lb-ft)
Valve Adjuster Locknuts: 16-18 Nm (12-13 lb-ft)
Oil Pan Bolts: 10-12 Nm (7-9 lb-ft)
Water Pump Mounting Bolts: 20-25 Nm (15-18 lb-ft)
Turbocharger Mounting Nuts: 30-35 Nm (22-26 lb-ft)
Starter Motor Mounting Bolts: 35-40 Nm (26-30 lb-ft)
The Yanmar 4LH-HTE is engineered specifically for marine propulsion
applications requiring 140 horsepower. The engine is suitable for
planing and semi-displacement vessels up to 11 meters (36 feet) overall
length depending on hull design and displacement.
Powerboat Applications:
Planning Cruisers (Shaft Drive Configuration): Fast cruisers and
sportfishing boats requiring 30-40 knot cruise speeds; typical vessels
9-11 m (30-36 ft) overall length.
Downeast and Semi-Displacement Boats: Vessels operating at 15-25 knot
cruise speeds with intermittent wide-open throttle.
Day Boats and Runabouts: Single-engine installations for family cruisers
and sport boats.
Commercial Applications:
Patrol Boats: Law enforcement and government vessels requiring sustained
high-speed operation.
Work Boats: Light commercial applications including water taxis, pilot
boats, and small landing craft.
Emergency Response: Fire rescue boats and RIBs up to 11 meters.
Sailboat Applications (with reduction
gear):
Large Auxiliary Propulsion: Sailboats to 20 m (65 ft) displacement using
appropriate propeller reduction.
Motor Sailers: Auxiliary power for sail-assisted vessels.
Repower Applications: The 4LH-HTE is a popular repower engine for older
vessels equipped with Yanmar 4LH, 4JH, or competitive marine diesel
engines from Volvo Penta, Cummins, and Perkins. The SAE 3 bellhousing
pattern allows adaptation to numerous 1:1 and reduction gears.
Gearbox Applications by Ratio: KMH5A 2.63:1 (Std): Most common selection
for planing boats 10-11 m (33-36 ft) with 19-21 in propellers. KMH4A
2.21:1: Light, fast planing hulls with 17-19 in propellers. KMH5A
2.47:1: Compromise ratio for mid-range boat lengths. KMH5A 2.00:1:
Speed-critical applications with small-diameter, high-pitch propellers
on very light planing hulls.
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