Part of the Yanmar Parts Manuals.
Halfway through a 4TNE98 teardown, with the crankpin bearings out and the ring lands cleaned up, the next hour goes to matching what you measured against part numbers. Guess wrong and the rebuild sits on the stand for another week waiting on a second order.
This is Yanmar publication Y00R4580, the factory parts catalog for the 4TNE98-SA and 4TNE98-G1A diesel engines: 21 pages organized by system, from cylinder block, cylinder head and bonnet, camshaft, and crankshaft and piston through the fuel injection pump, injection valves, governor, cooling water system, and feed pump, with bookmarks for each section. It lists the 0.25 undersize main bearings, the 80X80L lube oil filter, and a complete gasket set down to O-rings and seal washers.
Working alone with nobody to ask, the correct part number is the answer. Buy the PDF once and it stays on your bench as long as this engine does.
What's Inside This Yanmar 4TNE98-SA, 4TNE98-G1A Parts Manual
| System | Pages | Key Topics |
|---|---|---|
| Cylinder Block | 1 | Cylinder Block Assembly, Main Bearings, Camshaft Bushings, Head Bolts, Cylinder Head Gasket |
| Gear Housing | 2 | Gear Housing Cover, Lube Oil Pump, Tachometer Gear Unit, Oil Supply Cap, Seals and O-Rings |
| Flywheel Housing & Oil Sump | 3 | Flywheel Housing, Oil Sump Assembly, Drain Plug, Oil Seal, Flywheel Cover Cap |
| Cylinder Head & Bonnet | 4 | Cylinder Head Assembly, Rocker Arm Shaft, Valve Guides, Intake/Exhaust Valves, Valve Springs, Nozzle Seats, Bonnet Gasket |
| Suction Manifold | 5 | Intake Manifold, Manifold Gasket, Air Heater, Earth Cord |
| Exhaust Manifold | 6 | Exhaust Gasket, Stud Bolts, Manifold Nuts |
| Camshaft & Driving Gear | 7 | Camshaft Assembly, Tappets, Push Rods, Camshaft Gear, Idle Gear Assembly, Idle Shaft, Fi-P Gear |
| Crankshaft & Piston | 8 | Crankshaft, Flywheel Assembly, Ring Gear, Pistons with Rings, Piston Pins, Connecting Rods, Crankpin Bearings, V-Pulley |
| Lub. Oil System | 9 | Oil Dipstick, Lube Oil Filter 80X80L, Oil Pressure Switch, Lube Oil Pipe, O-Rings, Seal Washers |
| Cooling Water System | 10 | Water Pump, Thermostat, Water Temperature Switch |
| Fuel Injection Pump | 11-12 | Fuel Injection Pump Assembly, Delivery Valves, Plungers, Pump Housing, Fuel Injection Timing |
| Fuel Injection Valve | 13 | Fuel Injection Nozzle, Nozzle Holder, Pressure Spring, Nozzle Cap Nut, Injection Valve Assembly |
| Fuel Line | 14 | Fuel Supply Pipes, Fuel Return Lines, Fuel Filter, Fuel Line Fittings and Joints |
| Engine Stop Device | 15 | Engine Stop Solenoid, Stop Device Assembly, Fuel Shutoff Mechanism |
| Starting Motor | 16 | Starting Motor Assembly, Pinion Gear, Brush Set, Magnetic Switch, Motor Housing |
| Generator | 17 | Alternator Assembly, Rotor, Voltage Regulator |
| Gasket Set | 18 | Complete Gasket Set, Cylinder Head Gasket, Manifold Gaskets, O-Rings and Seal Washers |
| Governor | 19-20 | Mechanical Governor Assembly, Governor Springs, Flyweights, Control Lever, Governor Housing |
| Feed Pump | 21 | Fuel Feed Pump Assembly, Pump Valves, Priming Handle |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Thermo switch operating temperature | 110 C | p. 10 |
| Plug Size | PT3/8 | p. 1 |
| Main Bearing Undersize | 0.25 | p. 1 |
| O-Ring Size | P20 | p. 2 |
| Drain Plug Size | M22 | p. 3 |
| Nut Size | M8XP1.0 | p. 4 |
| Circlip Size | 18 | p. 4 |
| Oil Filter Size | 80X80L | p. 9 |
| Thermo Switch Temperature | 110 C | p. 10 |
Yanmar 4TNE98-SA, 4TNE98-G1A Common Problems This Manual Covers
Hard starting from fuel delivery problems
Cold no-starts on these engines often trace to a clogged fuel filter or aged supply hoses pulling air into the system overnight. The Fuel Line section lists the filter, supply and return pipes, and every fitting and joint you need to renew the run from tank to pump.
Manual Section: Fuel Line p. 14Overheating under load
A tired water pump, a stuck thermostat, or blocked hoses will push this engine hot fast. The Cooling Water System section carries part numbers for the pump, thermostat, water temperature switch, and all hoses and clamps, so you can replace the whole circuit in one order.
Manual Section: Cooling Water System p. 10Coolant loss and head gasket failure
Combustion gas bubbling into the coolant means the head gasket is done, and half-sealing it with reused gaskets just repeats the job. The Gasket Set section lists the cylinder head gasket along with the oil sump and manifold gaskets, O-rings, and seal washers for a clean reassembly.
Manual Section: Gasket Set p. 18Injectors dribbling, smoking, or knocking
Worn nozzles show up as rough running and smoke that no filter change fixes. The Fuel Injection Valve section breaks out the nozzle, nozzle holder, pressure spring, and cap nut so you can rebuild or replace each injector individually.
Manual Section: Fuel Injection Valve p. 13Worn bearings and rings at teardown
Once the crank is out and measured, you need exact numbers for crankpin bearings, pistons with rings, piston pins, and connecting rods before anything goes back together. The Crankshaft & Piston section lists all of them, and the Cylinder Block section covers the mains, including 0.25 undersize.
Manual Section: Crankshaft & Piston p. 8Engine refuses to shut down
A failed stop solenoid leaves you stalling the engine by hand every time. The Engine Stop Device section lists the solenoid and the complete fuel shutoff assembly.
Manual Section: Engine Stop Device p. 15Starter clicks but will not crank
Worn brushes, a sticking pinion gear, or a dead magnetic switch are common on high-hour engines. The Starting Motor section lists the complete motor assembly plus the brush set, pinion, and switch, so you can repair the starter instead of replacing it outright.
Manual Section: Starting Motor p. 16Frequently Asked Questions
Which engines does this parts catalog cover?
It covers the Yanmar 4TNE98-SA and 4TNE98-G1A diesel engines. It is Yanmar publication Y00R4580, and the same part listings apply whether your engine sits in a machine or on a stand.
Is this a service manual with torque specs and clearances?
No. This is the factory parts catalog: it identifies part numbers for every assembly, from cylinder block to feed pump, so you order correctly. It does not contain repair procedures, torque sequences, or clearance tables. Pair it with a service manual if you need those.
Does it cover the fuel injection pump internals?
Yes. The Fuel Injection Pump section spans two pages and lists the pump assembly plus delivery valves, plungers, and the pump housing, with the mechanical Governor and Feed Pump broken out in their own sections. p. 11
What parts does it list for the lube oil system?
The Lub. Oil System section lists the oil dipstick, the 80X80L lube oil filter, oil pressure switch, lube oil pipe, O-rings, and seal washers, so an oil leak or a dead pressure light can be ordered for from one page. p. 9
What format is this manual in?
Immediate download of the complete 21-page searchable Parts Catalog. Access it on any device, from a laptop at your desk to a phone in the field.
Can I print specific sections of 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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