Yanmar TS50 Specifications
| Engine Model: Yanmar TS50 |
| Engine Type: 4-stroke 1-cylinder horizontal water-cooled diesel |
| Total Displacement: 16.4 cu.in (0.27 L) |
| Rated Engine Power: 5 Hp (3.7 kW) at 2400 rpm |
| Fuel System Type: Indirect injection |
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The Yanmar TS50 is the smallest and most
compact model within the TS series of horizontal diesel engines.
Designed as a single-cylinder, 4-stroke water-cooled power unit, this
engine was developed for light-duty agricultural and industrial
applications requiring a balance of portability, reliability, and low
operating costs. The TS50 utilizes an indirect injection combustion
system of the swirl type, a technology that provides smoother operation
and reduced combustion noise compared to direct injection designs of its
era.
The Yanmar TS50 is a horizontal engine, a configuration that lowers the
overall height of the power unit, making it suitable for installation in
compact machinery where vertical space is constrained. The engine
employs a swirl pre-combustion chamber system, which promotes thorough
mixing of air and fuel before ignition, resulting in efficient
combustion across the operating speed range.
The engine is started manually via a hand crank and is available in two
cooling configurations: the TS50H with a hopper tank for simple
thermo-siphon cooling and the TS50C with a radiator for pressurized
circulation cooling. The TS50 was commonly installed in small water
pumps, portable generators, and light power tillers, where its
reputation for reliability and ease of maintenance made it a favored
choice for small-scale agricultural operations.
The Yanmar TS50 is a water-cooled, four-stroke, naturally aspirated
diesel engine configured for horizontal mounting in light-duty
machinery. The engine is available in two cooling system variants
sharing identical displacement and power output characteristics.
Engine Type: Horizontal, single-cylinder, 4-stroke, water-cooled diesel
Displacement: 0.269 liters (269 cc / 16.4 cu.in)
Bore and Stroke: 70.0 mm (2.76 in) x 70.0 mm (2.76 in)
Compression Ratio: 22.0:1
Combustion System: Indirect injection (swirl type / pre-combustion
chamber)
Firing Order: 1 (single cylinder)
Maximum Output: 3.7 kW (5.0 Hp) at 2,400 rpm
Continuous Rating: 3.0 kW (4.0 Hp) at 2,400 rpm
Maximum Torque: 14.7 Nm (10.8 lb-ft) at 1,600 rpm
Idle Speed: 700-800 rpm
Maximum Engine Speed: 2,400 rpm (governor limited)
Direction of Rotation: Counter-clockwise (viewed from flywheel side)
Fuel Tank Capacity: 5.8 liters (1.53 US gal)
Lubricating Oil Capacity: 1.6 liters (1.7 US qt)
The cylinder block is constructed from cast iron, a material selected
for its exceptional rigidity, vibration-damping properties, and
long-term dimensional stability under the elevated cylinder pressures of
diesel combustion. The single-cylinder configuration provides a compact,
lightweight engine package suitable for portable and space-constrained
applications. The horizontal orientation lowers the engine’s center of
gravity and reduces overall height.
The block features an open-deck design with a cast-in-place cylinder
bore machined directly into the iron casting. The wet-type cylinder
liner is replaceable, allowing the engine block to be reused through
multiple overhaul cycles. The block incorporates two main bearing webs
with two-bolt main bearing caps. The crankshaft is supported by two main
bearings and is constructed from forged steel. A cast aluminum or
stamped steel oil pan is sealed to the lower crankcase, providing the
oil reservoir.
Block Material: Cast iron
Bore Diameter (finished): 70.0 mm (2.76 in)
Cylinder Liner Type: Cast iron or aluminum alloy with cast iron rings
Main Bearing Caps: Cast iron, two-bolt design
The cylinder head is manufactured from cast iron, matching the block
material to ensure uniform thermal expansion across the cylinder head
gasket interface. This all-iron construction provides exceptional
durability and resistance to thermal cycling. The head incorporates the
swirl pre-combustion chamber of the replaceable insert type, which
creates controlled turbulence in the air-fuel mixture before ignition,
reducing combustion noise and improving cold-start performance.
The valvetrain is of overhead valve (OHV) design. The camshaft is
located in the cylinder block and is driven by gears from the
crankshaft. Valves are actuated by pushrods and rocker arms, with one
intake valve and one exhaust valve per cylinder. Valve clearance is
adjusted manually via threaded adjusters on the rocker arms. The
pre-combustion chamber insert is accessible for service and replacement
after extended operation.
Head Material: Cast iron
Valve Configuration: OHV, 2 valves per cylinder with pushrods and rocker
arms
Valve Clearance (Cold): 0.20 mm (0.008 in) for both intake and exhaust
The TS50 employs an indirect injection system utilizing a swirl
pre-combustion chamber. A Bosch-type mechanical in-line injection pump
delivers fuel at high pressure through an individual injection line to
the injector nozzle mounted in the pre-combustion chamber insert. The
injection pump is mechanically governed, with a centrifugal governor
controlling fuel delivery based on engine speed and load. Speed control
is provided by a hand lever or fixed-speed setting for constant-speed
applications such as generators.
The swirl pre-combustion chamber creates controlled turbulence in the
injected fuel before combustion propagates into the main combustion
chamber. This design reduces combustion noise allows for smooth
operation across a wide range of engine speeds, and improves cold-start
performance compared to direct injection systems of the era. A manual
fuel shut-off lever provides positive engine shutdown.
Injection Type: Indirect injection (swirl pre-combustion chamber)
Injection Pump: Bosch-type mechanical in-line pump
Injection Timing: Static timing marks on injection pump drive gear
Fuel Requirement: Diesel fuel meeting applicable standards
Fuel Filter: Inline type, replaceable
The lubrication system is a fully pressurized, wet-sump design utilizing
a trochoid-type oil pump. This pump type provides consistent oil flow
with reduced pulsation compared to gear-type pumps. The oil pump draws
lubricant from the oil pan through a mesh strainer and circulates it
through a full-flow, replaceable oil filter before entering the main oil
gallery.
From the gallery, pressurized oil is distributed to the crankshaft main
bearings, connecting rod bearing, camshaft bearings, rocker arm
assemblies, and timing gears. A pressure relief valve integrated with
the oil pump maintains system pressure within operational limits to
prevent over-pressurization during cold starts or high engine speeds.
Oil Type: SAE 30, 10W-30, or 15W-40 (API CD, CE, CF, or higher)
Oil Capacity (total): 1.6 liters (1.7 US qt)
Oil Pump Type: Trochoid-type
The TS50 is available with two distinct cooling system configurations.
The TS50H (Hopper) variant utilizes a simple open hopper tank mounted to
the cylinder. Cooling water is filled manually into the hopper, and
thermo-siphon circulation draws hot water from the cylinder jacket to
the top of the hopper for natural heat dissipation. This system has no
moving parts and requires no water pump.
The TS50C (Radiator) variant employs a pressurized radiator with a
belt-driven centrifugal water pump. Coolant is circulated through the
engine block, cylinder head, and radiator. Cooling air is drawn through
the radiator by a flywheel-mounted fan. A wax-pellet or bellows-type
thermostat regulates coolant flow to maintain optimal operating
temperature on some variants. This system provides more consistent
temperature control under varying loads.
Coolant Type (TS50C): Clean fresh water with corrosion inhibitor or
inhibited ethylene glycol antifreeze.
Coolant Capacity (Hopper - TS50H): 3.0-4.0 liters (0.8-1.1 US gal).
Coolant Capacity (Radiator - TS50C): 2.0-2.5 liters (0.5-0.7 US gal).
Water Pump Type (TS50C): Centrifugal, belt-driven.
Radiator Cap Pressure (TS50C): 50-70 kPa (7-10 psi).
| Intake and Exhaust Systems |
Intake System: Cast iron intake manifold with a single inlet from the
air cleaner. The intake system incorporates a dry-type paper filter
element or oil-bath air cleaner depending on application.
Exhaust System: Cast iron exhaust manifold with a downward-facing
outlet. A spark arrestor muffler is provided for generator and pump
applications.
Starting System: Hand-crank (manual) starting system. A starting crank
is inserted into the front pulley and rotated 1/4 turn after
decompression lever engagement to build momentum before release,
allowing the compression stroke to start the engine. A decompression
lever is incorporated into the cylinder head to release compression
during starting.
Governor System: Mechanical centrifugal governor with speed control
lever for variable-speed applications. Fixed-speed governor setting
available for constant-speed generator applications.
Dry Weight (TS50H - Hopper): 56 kg (123 lb)
Dry Weight (TS50C - Radiator): 60 kg (132 lb)
Overall Length (approx.): 562 mm (22.1 in)
Overall Width (approx.): 285 mm (11.2 in)
Overall Height (approx.): 403 mm (15.9 in)
Oil Change Interval: 100 hours of operation under normal conditions.
Oil Change Interval: 50 hours under severe conditions.
Oil Filter Change: At every oil change.
Fuel Filter Replacement: 200 hours or annually.
Air Filter Cleaning / Replacement: 50 hours (oil-bath); 100 hours (dry
element).
Valve Clearance Adjustment: Inspect and adjust every 200 hours.
Valve Clearance (Intake and exhaust): 0.20 mm (0.008 in) cold.
Injection Nozzle Inspection: 500 hours; replace as indicated by spray
pattern degradation.
Coolant Change (TS50C): 500 hours or annually.
Hopper Water Refill (TS50H): Check daily; refill as required.
Cylinder Head Bolt Retorque: 50 hours after overhaul or head gasket
replacement.
Idle Speed Adjustment: 700-800 rpm; adjust via idle speed screw on
injection pump.
Cylinder Head Nuts (M8 x 1.25), 1st pass: 20-25 Nm (15-18 lb-ft)
Cylinder Head Nuts (M8 x 1.25), final pass: 35-40 Nm (26-30 lb-ft)
Main Bearing Cap Bolts (M10 x 1.25): 45-50 Nm (33-37 lb-ft)
Connecting Rod Cap Bolts (M8 x 1.0): 25-28 Nm (18-21 lb-ft)
Rocker Arm Shaft Bracket Bolts (M8 x 1.25): 18-22 Nm (13-16 lb-ft)
Intake / Exhaust Manifold Nuts (M8 x 1.25): 16-20 Nm (12-15 lb-ft)
Injector Nozzle Holder (M24 x 1.5): 50-60 Nm (37-44 lb-ft)
Glow Plug (if equipped): 15-20 Nm (11-15 lb-ft)
Oil Pan Bolts (M6 x 1.0): 8-10 Nm (71-89 lb-in)
Water Pump Bolts (M8 x 1.25) (TS50C): 18-22 Nm (13-16 lb-ft)
Flywheel Nut (M20 x 1.5): 80-100 Nm (59-74 lb-ft)
Crankshaft Pulley Nut (M18 x 1.5): 60-80 Nm (44-59 lb-ft)
Injection Pump Drive Gear Nut (M12 x 1.5): 45-50 Nm (33-37 lb-ft)
The Yanmar TS50 engine was utilized exclusively in light-duty
agricultural, industrial, and portable machinery applications.
Water Pumps: Portable single-stage centrifugal pumps for irrigation and
dewatering applications.
Portable Generators: Small diesel generator sets (3.0-3.5 kW continuous
rating) for backup power and remote construction sites.
Power Tillers: Small two-wheel walking-type tillers for small-plot
agricultural preparation.
Small Agricultural Machinery: Rice transplanters, small threshers, and
feed grinders.
Marine Auxiliary: Small auxiliary power for on-board battery charging
and pump operation on small sailing vessels (limited applications).
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