Yanmar 4LV195 Specifications
| Engine Model: Yanmar 4LV195 |
| Engine Type: 4-stroke inline 4-cylinder turbocharged water-cooled diesel |
| Total Displacement: 168 cu.in (2.75 L) |
| Rated Engine Power: 192 Hp (143 kW) at 3500 rpm |
| Fuel System Type: Common rail direct injection |
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The Yanmar 4LV195 is a 4-stroke, vertical,
water-cooled marine diesel engine introduced in 2017 as the successor to
the 4LH and 4BY series. This 2.8-liter inline-four powerplant was
engineered to deliver a substantial increase in power density while
simultaneously reducing noise, vibration, and emissions. The Yanmar
4LV195 achieves these objectives through the application of
automotive-grade common rail fuel injection, a high-efficiency
turbocharger with charge air cooling, and a compact structural
architecture.
The engine’s design philosophy centered on meeting stringent exhaust
emission standards - IMO Tier 2, EPA Tier 3, and RCD 2016 - while
providing reliable propulsion for planing powerboats up to 10 meters (33
feet), coastal cruisers, and light commercial vessels. The Yanmar 4LV195
utilizes a Denso common rail system operating at pressures up to 1,800
bar (26,100 psi), enabling precise control of injection timing and fuel
quantity across the engine speed range.
The cylinder block and cylinder head are constructed from cast aluminum
alloy, reducing dry weight to 334 kg (736 lb) for the bobtail
configuration. The engine is offered with multiple transmission mounting
options, including the KMH50A hydraulic clutch with an 8-degree
down-angle, the KMH50V V-drive with a 12-degree angle, and compatibility
with the ZT370 sterndrive for inboard-outboard applications.
Engine Type: Vertical inline 4-cylinder, 4-cycle, turbocharged,
water-cooled diesel.
Displacement: 2.755 L (168 cu.in).
Bore: 92.0 mm (3.62 in).
Stroke: 103.6 mm (4.08 in).
Compression Ratio: 15.0:1.
Combustion System: Direct injection with common-rail fuel system.
Firing Order: 1-3-4-2.
Maximum Power Output (crankshaft): 143 kW (192 hp) @ 3,500 rpm.
Continuous Power Output (crankshaft): 110 kW (148 hp) @ 3,000 rpm.
Maximum Torque Output: 495 Nm (365 lb-ft) @ 2,000-2,600 rpm.
Idle Speed: 700-750 rpm.
Direction of Rotation: Counter-clockwise when viewed from the stern
(flywheel side).
The cylinder block is manufactured from cast aluminum alloy using
high-pressure die-casting techniques. This material selection reduces
overall engine mass while maintaining sufficient structural rigidity for
turbocharged operation. The block incorporates a closed-deck design with
cast-in-place, replaceable gray iron cylinder liners. The liners are
centrifugally cast and finished with a plateau honing process that
optimizes oil retention and piston ring sealing.
Bore diameter measures 92.0 mm (3.62 in) with a piston stroke of 103.6
mm (4.08 in), yielding a total displacement of 2.755 L (168 cu.in). This
under-square bore-to-stroke ratio (0.888) strongly favors low-end torque
generation, aligning with marine propulsion requirements where sustained
operation at moderate engine speeds is standard. The long-stroke design
also contributes to improved thermal efficiency and reduced fuel
consumption.
The crankshaft is forged from chromium-molybdenum steel with
induction-hardened journal surfaces. Five main bearings support the
crankshaft. Thrust washers positioned at the center main bearing control
axial crankshaft play. Connecting rods are forged from high-carbon steel
with a fracture-split big end design. Pistons are cast aluminum with a
low-expansion silicon alloy, featuring two compression rings and one oil
control ring. The piston crown incorporates a re-entrant combustion bowl
specifically designed for the Denso common rail injection spray pattern
and the 15.0:1 compression ratio.
The cylinder head is manufactured from cast aluminum alloy with a
cross-flow design positioning intake ports on the inlet side and exhaust
ports on the exhaust side. The combustion chambers are of the pent-roof
configuration with four valves per cylinder and a centrally located fuel
injector.
Each cylinder head contains 16 valves: eight intake valves and eight
exhaust valves. Intake valve diameter measures 31.0 mm (1.22 in), while
exhaust valve diameter measures 27.0 mm (1.06 in). Valve stem diameter
is 6.0 mm (0.24 in) for both intake and exhaust. The valvetrain utilizes
roller rocker arms and hydraulic lash adjusters, eliminating the need
for periodic valve clearance adjustments.
The camshafts are driven by a silent-type timing chain with a pitch of
8.0 mm (0.31 in). The chain routes from the crankshaft sprocket to the
exhaust camshaft sprocket, with a second chain segment connecting the
exhaust camshaft to the intake camshaft. An automatic hydraulic
tensioner maintains consistent chain tension throughout the engine’s
service life. The timing chain is designed for the life of the engine
under normal operating conditions.
The 4LV195 employs a Denso common-rail direct injection system operating
at high pressure. A high-pressure pump, driven by the timing chain,
supplies fuel to the common rail accumulator. The pump is a radial
piston type with quantity control, delivering only the fuel volume
required for current operating conditions. Fuel rail pressure is
regulated up to 1,800 bar (26,100 psi) under high-load conditions.
The injectors are solenoid-actuated units with multi-hole nozzles.
Multiple injection events per combustion cycle - including pilot
injection, main injection, and post-injection - are utilized to reduce
combustion noise, lower NOx and particulate emissions, and enable
smoother engine operation.
The injection timing and fuel quantity are controlled by the engine
control unit based on inputs from the crankshaft position sensor,
camshaft position sensor, rail pressure sensor, coolant temperature
sensor, intake air temperature sensor, boost pressure sensor, and
throttle position sensor. The fuel system incorporates a primary fuel
filter with water separator and a secondary high-efficiency cartridge
filter. A hand primer is provided for system priming after filter
replacement.
The lubrication system utilizes a forced-feed, full-flow design with a
gear-type oil pump mounted to the front of the crankshaft. A pressure
relief valve integrated into the pump maintains system pressure within
design parameters.
Total oil capacity is 11.5 L (12.2 qt) including filter. Recommended oil
viscosity is SAE 5W-30 or 5W-40 meeting API CJ-4 or ACEA E9
specifications. These low-ash formulations are required for
compatibility with the engine’s emissions aftertreatment system where
equipped. Oil pressure specifications require a minimum of 1.0 bar (15
psi) at warm idle and 4.0-5.0 bar (58-73 psi) at 3,000 rpm.
The oil filter is a spin-on, full-flow type mounted to the cylinder
block. A liquid-to-oil plate-type oil cooler is integrated into the
lubrication system, utilizing engine coolant to stabilize oil
temperature. The oil pan is cast aluminum with internal baffling and a
sump designed for operation at vessel trim angles up to 15 degrees
continuous and 25 degrees intermittent.
The cooling system is a closed-loop freshwater system with a heat
exchanger for seawater cooling. A centrifugal fresh water pump, driven
by the accessory drive belt, circulates coolant through the cylinder
block, cylinder head, oil cooler, and charge air cooler.
A rubber impeller-type seawater pump, mounted on the front of the
engine, draws raw water through a through-hull fitting and strainer,
then circulates it through the heat exchanger and the charge air
intercooler before discharging to the exhaust injection elbow. The
thermostat is a wax-pellet unit with an opening temperature of 82-86 °C
(180-187 °F). A bypass circuit allows fresh water circulation within the
engine during warm-up.
Total fresh water coolant capacity is 8.5 L (9.0 qt). The heat exchanger
is a shell-and-tube design with a seawater-cooled tube bundle. Zinc
anodes are installed in the seawater circuit to prevent galvanic
corrosion. System pressure is controlled by a pressure cap rated at 1.0
bar (15 psi) on the fresh water fill neck.
The exhaust manifold is manufactured from cast iron with a water-cooled
jacket. Seawater is injected into the exhaust stream at the turbocharger
outlet to cool exhaust gases before they enter the rubber exhaust hose
and gooseneck fitting.
The engine is equipped with a 12-volt alternator rated at 130 amperes,
driven by a poly-V belt from the crankshaft pulley. The starting system
includes a 2.0 kW electric starter motor with sealed construction for
marine environment protection.
Aspiration System: The 4LV195 is equipped with a fixed geometry
turbocharger manufactured by Mitsubishi. Maximum boost pressure ranges
from 1.6-2.0 bar (23-29 psi) absolute depending on engine speed and
load. A seawater-cooled charge air intercooler (aftercooler) reduces
intake air temperature by 50-70 °C (90-126 °F) under sustained boost
conditions, increasing charge density and reducing thermal stress on the
combustion system.
Engine Management: The Yanmar electronic control system integrates
control of fuel injection, boost pressure, idle speed, cooling system
operation, and diagnostic monitoring. The engine is compatible with
Yanmar VC10 or VC20 Vessel Control Systems for full electronic
single-lever throttle and shift operation. Mechanical control systems
are available as an option for installations requiring simplified
wiring.
Crankcase Ventilation: A closed-loop crankcase ventilation system routes
blow-by gases from the valve cover through an oil separator, returning
condensed oil to the sump while directing vapor to the intake system
upstream of the turbocharger compressor inlet.
Transmission Options: KMH50A Hydraulic Multi-Disc Clutch: 8-degree
down-angle. Combined dry weight with engine: 384 kg (846 lb). Forward
ratio 1.40:1 or 1.66:1. Reverse ratio 1.40:1 or 1.66:1. KMH50V V-Drive:
12-degree angle. Combined dry weight with engine: 407 kg (897 lb).
Forward ratio 1.40:1 or 1.66:1. Reverse ratio 1.40:1 or 1.66:1. ZT370
Sterndrive: Compatible with the 4LV195Z model for inboard-outboard
applications.
Overall Length (bobtail, without gearbox): 785 mm (30.9 in) measured
from front pulley face to flywheel housing flange.
Overall Width: 720 mm (28.3 in).
Overall Height: 780 mm (30.7 in) from oil pan bottom to engine top.
Dry Weight (bobtail without gearbox): 334 kg (736 lb).
Valve Clearance: Hydraulic lash adjusters operate automatically.
Timing Chain: Inspection recommended at 1,000 operating hours.
Fuel Filter Replacement Interval: 250 hours or 12 months for primary
filter.
Fuel Filter Replacement Interval: 500 hours for secondary filter.
Engine Oil Change Interval: 250 hours or 12 months, whichever occurs
first.
Oil Filter Replacement Interval: Replace with every oil change.
Coolant Change Interval: 500 operating hours or 24 months.
Seawater Pump Impeller Inspection Interval: 200 hours.
Seawater Pump Impeller Replacement Interval: 500 hours or 24 months.
Charge Air Intercooler Cleaning Interval: 500 hours.
Heat Exchanger Zinc Anode Inspection: 250 hours.
Valve Inspection: Every 800 hours.
Compression Pressure: Minimum 2.8 MPa (406 psi.
Injector Testing Interval: Every 800 hours.
Cylinder Head Bolts, Step 1: 30 Nm (22 lb-ft).
Cylinder Head Bolt, Step 2: 60 Nm (44 lb-ft).
Crankshaft Damper Pulley Bolt: 200-210 Nm (148-155 lb-ft).
Connecting Rod Cap Bolts: 35-40 Nm (26-30 lb-ft).
Main Bearing Cap Bolts: 60-65 Nm (44-48 lb-ft).
Flywheel Bolts: 90-100 Nm (66-74 lb-ft).
Camshaft Sprocket Bolts: 50-60 Nm (37-44 lb-ft).
Camshaft Bearing Cap Bolts: 20-25 Nm (15-18 lb-ft).
Valve Cover Bolts: 8-10 Nm (6-7 lb-ft).
Intake Manifold Bolts: 18-22 Nm (13-16 lb-ft).
Exhaust Manifold Nuts: 25-30 Nm (18-22 lb-ft).
Turbocharger Mounting Nuts: 35-40 Nm (26-30 lb-ft).
Turbocharger Oil Feed Line: 20-25 Nm (15-18 lb-ft).
Turbocharger Coolant Lines: 25-30 Nm (18-22 lb-ft).
Oil Pan Bolts: 8-12 Nm (6-9 lb-ft).
Timing Chain Tensioner: 20-25 Nm (15-18 lb-ft).
Timing Chain Guide Bolts: 10-12 Nm (7-9 lb-ft).
Fresh Water Pump Mounting Bolts: 15-20 Nm (11-15 lb-ft).
Seawater Pump Mounting Bolts: 15-20 Nm (11-15 lb-ft).
Thermostat Housing Bolts: 8-12 Nm (6-9 lb-ft).
Heat Exchanger Mounting Bolts: 20-25 Nm (15-18 lb-ft).
Common Rail Mounting Bolts: 20-25 Nm (15-18 lb-ft).
High-Pressure Fuel Pump Mounting Bolts: 25-30 Nm (18-22 lb-ft).
Fuel Injector Clamp Bolts: 25-30 Nm (18-22 lb-ft).
Glow Plugs: 15-20 Nm (11-15 lb-ft).
Crankshaft Position Sensor Mounting Bolt: 8-10 Nm (6-7 lb-ft).
Camshaft Position Sensor Mounting Bolts: 8-10 Nm (6-7 lb-ft).
Alternator Mounting Bracket Bolts: 25-30 Nm (18-22 lb-ft).
Starter Motor Mounting Bolts: 35-40 Nm (26-30 lb-ft).
Engine Mounts (to block): 50-55 Nm (37-41 lb-ft).
KMH50A Transmission Mounting Bolts: 45-50 Nm (33-37 lb-ft).
KMH50V Transmission Mounting Bolts: 45-50 Nm (33-37 lb-ft).
Recreational Powerboats: The 4LV195 is installed as primary propulsion
in planing powerboats from 7 to 10 meters (23-33 feet) in length,
including center consoles, walkaround cuddy cabins, deck boats, and
bowriders. The engine’s power density enables planing performance while
maintaining fuel economy at cruising speeds. Vessel applications include
hull designs from Boston Whaler, Grady-White, Robalo, Pursuit, and
EdgeWater.
Coastal Cruisers: Express cruisers and weekender models up to 9.5 meters
(31 feet) receive the 4LV195 in single-engine or twin-engine
configurations. The common-rail engine’s low vibration levels and
reduced noise characteristics enhance onboard comfort during overnight
trips. Manufacturers utilizing this engine include Beneteau, Jeanneau,
Monterey, Regal, and Four Winns.
Downeast and Semi-Displacement Boats: Downeast-style hulls and
semi-displacement cruisers from builders such as Parker, Eastern,
Southport, and Steiger Craft operate the 4LV195 for its combination of
high torque output at moderate engine speeds (2,000-2,600 rpm). The
engine’s maximum torque of 495 Nm at this range matches the power
requirements of these hull forms.
Light Commercial Vessels: Patrol launches, survey boats, pilot vessels,
and small workboats use the 4LV195 in applications where reliability,
extended service intervals, and electronic diagnostic capability are
required. The engine meets international emissions standards for
commercial operation in controlled waters.
Yacht Tenders and Chase Boats: Large yachts deploy 4LV195-powered
tenders where compact dimensions and low dry weight facilitate launching
and recovery from davits. The common-rail engine’s cold-start capability
(down to -15 °C / 5 °F without preheating) and electronic throttle
response suit the operational requirements of yacht tender service.
Sterndrive Applications (4LV195Z): The ZT370 sterndrive-compatible model
is installed in inboard-outboard configurations for boats where a
sterndrive offers advantages in trim control and shallow-water
operation. This configuration is common in bowriders, deck boats, and
small cabin cruisers from manufacturers including Chaparral, Crownline,
and Stingray.
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