Part of the Yanmar Parts Manuals.
An engine on a stand comes apart faster than it goes back together, and the part you cannot name is the part you cannot order. This Yanmar parts catalog, publication Y00B3601, identifies every component on the 3TNA72L-UB (K2103) three cylinder diesel, with the breakdown titled for the 3TNA72L-UBVM build. It runs the whole engine end to end: cylinder block, crankshaft and flywheel, piston and connecting rod, camshaft, fuel injection pump and valves, governor, cooling water pump, starting motor, generator, and glow plugs.
Each section pairs an exploded diagram with factory part numbers, so a worn bearing, a torn o-ring, or a stripped sump plug gets matched to the exact item instead of sitting apart another week while you guess. The catalog also lists 0.25 undersize main bearings and piston ring sets for regrind work.
It is a 56 page PDF with 28 bookmarked sections. Print the diagram you need and let it get dirty at the bench; the file stays clean.
What's Inside This Yanmar 3TNA72L-UB Parts Manual
| System | Pages | Key Topics |
|---|---|---|
| Engine 3TNA72L-UBVM | 1-2 | Cylinder Block, Gear Housing, Mounting Flange, Oil Seal Housing, Lub.Oil Sump, Cylinder Head, Rocker Arm, Bonnet, Air Cleaner, Suction & Exhaust Manifold, Silencer, Camshaft, Crankshaft & Flywheel, Piston & Connecting Rod, Driving Gear, Lub.Oil Pump, Lub.Oil Strainer, Cooling Water Pump, Thermostat, Fuel Injection Pump, Fuel Injection Valve, Fuel Line, Governor, Starting Motor, Generator, Glow Plug, Gasket Set & Special Tool |
| Lub. Oil Sump | 11-12 | Sump Assy, Plug, O-Ring, Spacer, Bolt |
| Lub. Oil Pump | 33-34 | Pump Assy, Gasket, Bolt |
| Lub. Oil Strainer | 35-36 | Bracket, Filter, O-Ring, Valve Assy, Pipe Assy, Nut |
| Gasket Set & Special Tool (Optional) | 55-56 | Gasket Set, Gasket, O-Ring, Flex Horn |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Main Bearing Undersize | 0.25 | p. 2 |
| Starter Voltage/Power | 12V-1.0W | p. 48 |
| V-Belt Type/Length | FM=36.5 | p. 36 |
| Governor Link Length (No Color) | 88.8 | p. 46 |
| Governor Link Length (White) | 88.6 | p. 46 |
| Governor Link Length (Red) | 89.0 | p. 46 |
| Piston Ring Set Undersize | 0.25 | p. 28 |
| Piston Bearing Undersize | 0.25 | p. 28 |
| O-Ring 1A P-32.0 Dimension | P-32.0 | p. 16 |
| O-Ring 1A S-25.0 Dimension | S-25.0 | p. 54 |
| O-Ring 1A S-24.0 Dimension | S-24.0 | p. 54 |
Yanmar 3TNA72L-UB Common Problems This Manual Covers
Low oil pressure after teardown or storage
A worn or sludge-packed oil pump will not hold pressure once the engine is back together. The Lub. Oil Pump section shows the pump assembly, gasket, and bolts, so you can order a complete replacement instead of resealing a tired pump.
Manual Section: Lub. Oil Pump p. 33Sludge starving the oil strainer
Neglected oil lets debris load up the strainer and filter, and metal particles that get past them end in bearing burn-in. The Lub. Oil Strainer section identifies the bracket, filter, o-ring, valve assembly, and pipe assembly for a clean refresh.
Manual Section: Lub. Oil Strainer p. 35Oil weeping from the sump
Drain plug threads and crushed sealing rings are common leak points on small diesels that get serviced often. The Lub. Oil Sump section lists the sump assembly, plug, o-ring, spacer, and bolts so you replace the seal, not just retighten it.
Manual Section: Lub. Oil Sump p. 11Hard starting when cold
Cold-weather starting complaints on this engine family often trace back to dead glow plugs or tired starter circuits. The Glow Plug section gives you the correct plug part numbers before you start swapping electrics at random.
Manual Section: Glow PlugWhite smoke and rough injection
Clogged or worn injection nozzles show up as white smoke and abnormal combustion noise. The Fuel Injection Valve section breaks down the injector assembly so you can order nozzles and seals for a proper refresh rather than reusing suspect parts.
Manual Section: Fuel Injection ValveSlow cranking, then nothing
Starter solenoids and motors on these engines fail after years of high-draw cranking. The Starting Motor section identifies the motor assembly and hardware, so the replacement matches what came off instead of a near-fit guess.
Manual Section: Starting MotorReassembly without fresh gaskets
Once the head and sump are off, reused gaskets are where leaks start. The Gasket Set & Special Tool (Optional) section lists the complete gasket set and o-rings, one order covering everything the rebuild disturbed.
Manual Section: Gasket Set & Special Tool (Optional) p. 55Frequently Asked Questions
Which Yanmar engines does this parts catalog cover?
It covers the Yanmar 3TNA72L-UB (K2103) diesel engine under factory publication number Y00B3601, with the parts breakdown titled for the 3TNA72L-UBVM build. If your nameplate shows any of those designations, this is the matching catalog.
Is this a service manual with torque specs and procedures?
No, this is the factory parts catalog: exploded diagrams and part numbers for every assembly from the cylinder block to the governor and starting motor. Use it to identify and order parts; for rebuild procedures and torque sequences you would pair it with a service manual.
What exactly do I get after purchase?
A 56 page English-language PDF (0.64 MB) delivered as an instant download. It carries 28 bookmarks, one per section, so you can jump straight to the diagram you need instead of scrolling.
Does it cover the lubrication system parts?
Yes. The Lub. Oil Pump section lists the pump assembly, gasket, and bolts, and the Lub. Oil Strainer section covers the filter, o-ring, valve assembly, and pipe assembly, so an oil pressure repair starts with the right part numbers. p. 33
Can I order a full gasket set for a rebuild?
Yes. The Gasket Set & Special Tool (Optional) section lists the complete engine gasket set plus individual gaskets and o-rings, so everything you disturbed during teardown goes back with fresh seals. p. 55
Is this Yanmar 3TNA72L-UB (K2103) & variants Parts Catalog a digital download?
A 56-page Parts Catalog in searchable PDF format, available the moment you complete checkout. View on computer, tablet, or phone, with no shipping wait.
Are there any print restrictions on this Yanmar 3TNA72L-UB (K2103) & variants?
Yes, print as many copies as you want, and there are no restrictions. Many mechanics print the section they need and bring it to the shop floor.
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