Part of the Yanmar Parts Manuals.
An engine in pieces on the stand raises questions nobody is around to answer: which undersize main bearing the reground crank takes, which nozzle assembly fits that holder, which O-ring seals the gear housing cover. This Yanmar parts catalog for the 3TNC80L-RB1 (SUM30) diesel settles them system by system, walking the cylinder block, crankshaft and piston, camshaft and driving gear, fuel injection pump, governor, cooling water system, and lubricating oil system through to the starting motor and generator.
Across 42 pages, every system gets a parts list matched to a numbered exploded view, so you can put an exact Yanmar part number on each piece you pull, down to gaskets, snap pins, and clamps. It even lists 0.25 undersize main and thrust bearings and closes with the optional gasket set and tools.
This is factory publication Y00B4731 in searchable PDF, in English, sized to live on the bench.
What's Inside This Yanmar 3TNC80L-RB1, SUM30 Parts Manual
| System | Pages | Key Topics |
|---|---|---|
| Engine 3TNC80L-RB1 | 1 | General Information |
| Cylinder Block | 2-3 | Block Assy, Cylinder, Plug, Bolt, Main Bearing, Bush, Camshaft, Gasket |
| Gear Housing | 4-5 | Housing Assy, Gear, Seal, Oil, Cap, LUB.OIL Supply, Gasket, O-Ring |
| Flywheel Housing & L.O. Sump | 6-7 | Repair Part |
| Cylinder Head & Bonnet | 8-10 | Viewed From a |
| Suc.Manifold & Air Cleaner | 11-12 | Manifold, Suction, Gasket, Heater, Air, Silencer, Air Cleaner Assy, Element |
| Exhaust Manifold & Silencer | 13-14 | Manifold, Exhaust, Gasket, Nut W/WASHER, Silencer, Stay |
| Camshaft & Driving Gear | 15-16 | Repair Part |
| Crankshaft & Piston | 17-18 | Repair Part |
| Lub. Oil System | 19-20 | Previous Model |
| Cooling Water System | 21-22 | Cylinder Head |
| Fuel Injection Pump | 23-26 | Classified Mark, Viewed From a |
| Fuel Injection Pipe | 27-28 | Valve Assy, F.INJECT, Nozzle Assy, Nut, Nozzle Case, Holder Assy, Nozzle |
| Fuel Pipe | 29-30 | To Feed Pump |
| Governor | 31-33 | Classified Mark |
| Engine Stop Device | 34-35 | Joint, Link, Bracket, Solenoid, Stop, Washer, Snap Pin |
| Starting Motor | 36-37 | Starter, Armature Assy, Bearing, Coil Assy, Field, Clutch Assy, Shaft, Pinion |
| Generator | 38-39 | Washer, Spring, Collar, Plate Assy, Stator, Flywheel Assy |
| Gasket Set (Optional) & Tool | 40-42 | Optional Parts |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Clamp size | 60 | p. 11 |
| Main Bearing Undersize | 0.25 | p. 2 |
| Thrust Bearing Undersize | 0.25 | p. 2 |
| O-Ring 1A P-type Size | 16.0 | p. 4 |
| Drain Plug Size | M22 | p. 6 |
| Stud M6x30 Plated | M6x30 | p. 8 |
| Valve Spring Quantity | 6 | p. 8 |
| Piston Pin Diameter | 23 | p. 17 |
| Circlip Size | 23 | p. 17 |
Yanmar 3TNC80L-RB1, SUM30 Common Problems This Manual Covers
Hard starting after storage
A 3TNC80L that sat all winter usually needs the fuel system bled and the lines checked for cracked pipes and loose clamps letting air in. The Fuel Pipe section maps every line and clamp from tank side to feed pump so you can order the pieces that leak.
Manual Section: Fuel Pipe p. 29White smoke and rough running
Contaminated fuel wears injection nozzles until spray pattern collapses, and the engine smokes white and loses power. The Fuel Injection Pipe section breaks down the nozzle assemblies, nozzle cases, and holder assemblies with part numbers for a full injector refresh.
Manual Section: Fuel Injection Pipe p. 27Overheating and coolant loss
Blocked passages, a tired water pump, or a slipping drive belt will push coolant temperature up fast on this engine. The Cooling Water System section shows the pump, thermostat, hoses, and the A-39 V-belt as numbered parts in one exploded view.
Manual Section: Cooling Water System p. 21Low oil pressure
Dirty oil and a neglected filter starve the bearings, and by the time the gauge shows it the damage is under way. The Lub. Oil System section identifies the pump, filter, and supply components so the lubrication side goes back together with fresh parts.
Manual Section: Lub. Oil System p. 19Reground crank needs undersize bearings
Once the journals are cut, standard shells are scrap. The Cylinder Block section lists 0.25 undersize main and thrust bearings alongside the block, bushes, and camshaft bearing parts, so you can order the right shells before the machine shop calls back.
Manual Section: Cylinder Block p. 2Starter drags or will not engage
A starter that clicks, spins without engaging, or drags on a cold morning usually comes down to the pinion clutch, armature, or field coil. The Starting Motor section breaks the starter into those assemblies so you can rebuild it instead of replacing it whole.
Manual Section: Starting Motor p. 36Resealing the engine after teardown
Reusing old gaskets on a fresh rebuild is how a clean assembly ends up weeping oil in a week. The Gasket Set (Optional) & Tool section lists the complete gasket set and the special tools in one order.
Manual Section: Gasket Set (Optional) & Tool p. 40Frequently Asked Questions
Which engine does this catalog cover?
It covers the Yanmar 3TNC80L-RB1 three-cylinder diesel, SUM30 specification, as factory publication Y00B4731. The opening page carries the engine overview and specifications before the parts sections begin. p. 1
Is this a service manual with repair procedures and torque specs?
No. This is the factory parts catalog: parts lists with Yanmar part numbers matched to exploded view drawings for every system, from Cylinder Block through Gasket Set. Use it to identify and order correct parts; step-by-step repair procedures are not included.
Can I look up injection pump and injector part numbers?
Yes. The Fuel Injection Pump section starts on page 23 with its parts list and classified marks, and the Fuel Injection Pipe section on page 27 covers the nozzle assemblies, nozzle cases, and holder assemblies. p. 23
Are undersize bearings listed for a reground crankshaft?
Yes. The Cylinder Block section lists 0.25 undersize main bearings and thrust bearings, so you can match shells to a crank that has been cut at the machine shop. p. 2
What format is this manual in?
This is a 42-page searchable PDF ready for immediate download. Works on any device, so pull it up on your phone while you're under the hood. No shipping, no waiting.
Am I able to print pages from this manual?
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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