Part of the Yanmar Parts Manuals.
A 4TN84L-RBB on the stand with the crank out is just a pile of castings until you can put a number on every piece of it, and the Crankshaft & Piston pages in this Yanmar parts catalog do exactly that, down to the 0.25 oversize pistons with rings and the 0.25 undersize main and thrust bearings a reground block calls for.
This is Yanmar publication Y00B4401, the factory parts catalog for the 4TN84L-RBB diesel engine, covering engines up to serial E/#08683. Its 37 pages of exploded diagrams take in the cylinder block, cylinder head, camshaft and driving gear, lubrication and cooling water systems, fuel injection pump and pipes, governor, generator, and both the previous and new starting motors.
Nothing stalls a rebuild like a gasket you cannot name. Every seal, O-ring, and fastener here carries its Yanmar part number, so the order you place is the order that fits.
What's Inside This Yanmar 4TN84L-RBB Parts Manual
| System | Pages | Key Topics |
|---|---|---|
| Engine | 1-2 | Cylinder Block Assy, Round Gasket, Main Bearing, Thrust Bearing, Camshaft Bush, Cylinder Head Gasket, Gasket |
| Suc./ Exh. Manifold & Air Cleaner | 11-12 | Camshaft Assy, Camshaft Gear, Thrust Bearing, Tappet, Push Rod, Idle Gear Shaft, Gear w/ Bush, Idle Gear Bush |
| Cooling Water System | 19-21 | Pump w/ Governor & Feed Pump, Camshaft, Thrust Ball Bearing, Cam Shaft Support, Plunger w/ Barrel, Retainer A, Plunger Spring Shoe, Plunger Spring |
| Starting Motor (Previous) | 30-31 | Starter, Armature Assy, Bearing, Field Coil Assy, Brush, Brush Holder Assy, Brush Spring, Rear Cover |
| Starting Motor (New) | 32-33 | Generator, Collar, Plate Assy, Stator, Coupler, Flywheel Assy, V-belt Adjuster |
| Gasket Set (Optional) & Tool | 36-37 | Gasket, CYL.HEAD, Liquid, O-Ring, Seal, Valve Stem |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Main Bearing Undersize | 0.25 | p. 2 |
| Thrust Bearing Undersize | 0.25 | p. 2 |
| O-Ring 1A P-16.0 | P-16.0 | p. 4 |
| Nut M8xP1.0 | M8xP1.0 | p. 8 |
| O-Ring 1A S-50.0 | S-50.0 | p. 8 |
| Clamp Size | 60 | p. 10 |
| Key Size | 7x14 | p. 12 |
| Piston W/Ring Oversize | 0.25 | p. 14 |
| V-Pulley Diameter | 120 | p. 18 |
Yanmar 4TN84L-RBB Common Problems This Manual Covers
Hard starting after sitting overnight
Air working into the fuel system through tired lines or a weeping pump is the classic cause of an engine that cranks clean but will not light. The Fuel Injection Pump section identifies the pump assembly and its related hardware by part number so you replace the leak, not just bleed around it.
Manual Section: Fuel Injection PumpOverheating and coolant loss
A failing water pump, stuck thermostat, or slipping V-belt will cook a small diesel quickly. The Cooling Water System section breaks out the pump assembly, thermostat, fan, V-pulley, and pipes so every worn piece can be ordered in one pass.
Manual Section: Cooling Water System p. 19Starter drags or fails to engage
Worn brushes, a tired pinion, or a lazy magnetic switch all show up as slow cranking or a starter that spins without turning the flywheel. This catalog covers both starter versions, with the earlier unit broken down in Starting Motor (Previous) and the later one in its own section.
Manual Section: Starting Motor (Previous) p. 30Low oil pressure and bearing wear
Contaminated oil or a clogged filter starves the mains and rod bearings long before the gauge tells the whole story. The Lub. Oil System section lays out the lubrication components by part number for a proper refresh during the rebuild.
Manual Section: Lub. Oil SystemBlack smoke and lost power
A choked air cleaner or restricted intake leans the engine into smoke and sluggish response under load. The Suc./ Exh. Manifold & Air Cleaner section lists the cleaner assembly, intake and exhaust manifolds, and their gaskets.
Manual Section: Suc./ Exh. Manifold & Air Cleaner p. 11Worn bore, slack ring end gap
When the bore is past its limit, boring to the next size only helps if the right pistons exist. The Crankshaft & Piston section lists the 0.25 oversize piston with rings along with the crankshaft components that go back in with it.
Manual Section: Crankshaft & PistonOil and coolant seepage from old gaskets
Hardened gaskets and valve stem seals weep long before they fail outright, and hunting them down one part number at a time wastes bench days. The Gasket Set (Optional) & Tool section lists the cylinder head gasket, O-rings, valve stem seals, and the optional full gasket set.
Manual Section: Gasket Set (Optional) & Tool p. 36Frequently Asked Questions
Which engine does this parts catalog cover?
It covers the Yanmar 4TN84L-RBB diesel engine, up to engine serial E/#08683. This is factory publication Y00B4401. It applies to the engine itself, whatever equipment it is installed in.
My engine has the newer starter. Is it covered?
Yes, both versions are. The Starting Motor (Previous) section covers the earlier unit and Starting Motor (New) covers the later one, each broken down to the armature assembly, field coil, brushes, and pinion so you can match what is on your engine. p. 30
Does it list undersize bearings and oversize pistons?
Yes. The catalog lists 0.25 undersize main and thrust bearings for a reground crankshaft, and a 0.25 oversize piston with rings for a rebored block, each with its own part number. p. 2
Is this a workshop manual with repair procedures?
No. It is the factory parts catalog: exploded diagrams and Yanmar part numbers for every assembly, from cylinder block to governor. Use it to identify and order correct parts during a rebuild; it does not include torque sequences, clearance specs, or step by step repair procedures.
How will I receive this Yanmar 4TN84L-RBB Parts Catalog?
Immediate download of the complete 37-page searchable Parts Catalog. Access it on any device, from a laptop at your desk to a phone in the field.
Is this Yanmar 4TN84L-RBB Parts Catalog printable?
The PDF is DRM-free. Print whatever sections you need to take out to the shop. Standard letter or A4 paper works.
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