Need the right numbers to rebuild your excavators engine? This 25-page Yanmar 3TNE78A-TBY, TB25FR Parts Catalog PDF gives you every exploded view and factory identifier for the complete powertrain. You get crystal-clear diagrams breaking down the cylinder head, gear housing, and fuel injection pump down to the smallest washer. Open to the cooling water system to find exact part numbers for the radiator, thermostat, and V-belt. Track down the exact O-ring for your hydraulic pump bracket, or find the factory replacement for the governors Angleich assembly before you tear anything apart. Stop ordering the wrong components and waiting weeks on shipping returns. Grab this bookmarked file, verify your part numbers right on your phone while standing at the machine, and get the correct order placed today.
What's Inside This Yanmar 3TNE78A-TBY Parts Manual
| System | Pages | Key Topics |
|---|---|---|
| Engine for TB25FR 3TNE78A-Tby | - | - |
| Cylinder Block | 1 | Main Bearing, Thrust Bearing, Camshaft Bush, Cylinder Head Bolt, Cylinder Head Gasket |
| Gear Housing | 2 | Oil Seal, Cover, Gasket, O-Ring |
| Flywheel Housing & Oil Sump | 3 | Flywheel Housing, Oil Sump, Drain Plug, Oil Seal, Gasket |
| Cylinder Head & Bonnet | 4-5 | Cylinder Head, Valve, Rocker Arm, Bonnet, Gasket, Valve Stem Seal |
| Suction Manifold % Air Cleaner | 6 | Suction Manifold, Air Cleaner, Air Heater, Air Cleaner Element, Unloader Valve |
| Exhaust Manifold & Silencer | 7 | Exhaust Manifold, Silencer, Gasket, Stud |
| Camshaft & Driving Gear | 8 | Camshaft, Driving Gear, Tappet, Push Rod, Idle Gear |
| Crankshaft & Piston | 9 | Crankshaft Assy, Crankshaft Gear, V-Pulley, Piston, Connecting Rod, Crankpin Bearing |
| Hydraulic Pump | 10 | Assy, Driving Set, Bracket, Ball Bearing |
| Lub. Oil System | 11 | Lub. Oil Pump Assy, Lub. Oil Dipstick, Oil Inlet Pipe, Oil Strainer, Oil Filter, Oil Pressure Sender |
| Cooling Water System | 12 | C.W. Pump, V-Belt, Fan, Thermostat, Radiator, Oil Cooler |
| Fuel Injection Pump | 13-14 | Assy, Camshaft, Plunger, Tappet, Delivery Valve, Control Rack |
| Governer | 15-16 | Governor Weight Assy, Control Shaft, Governor Lever, Governor Spring, Solenoid, Angleich Assy |
| Fuel Injection Valve | 17 | Assy, Nozzle Assy, Nozzle Holder, Nozzle Spring, Fuel Injection Pipe, Fuel Return Pipe |
| Fuel Line | 18 | Fuel Oil Filter, Taper Valve, Fuel Strainer, Fuel Pipe, Fuel Oil Pipe, Feed Pump |
| Staring Motor | 19 | Starter, Switch, Magnet, Armature Assy, Brush, Pinion Assy |
| Generator | 20 | Rotor Assy, Ball Bearing, Brush Assy, Diode Assy, Pulley |
| Gasket Set | 21 | Gasket, Cyl. Head, O-Ring, Seal, Seal Washer |
Yanmar 3TNE78A-TBY Common Problems This Manual Covers
Need to identify fuel injection pump components for Yanmar 3TNE78A-TBY engine that cranks but will not start p. 13
Check the Fuel Injection Pump exploded view on page 13. Locate the specific plunger, tappet, and delivery valve assemblies for your exact model. Verify the part numbers for the control rack before ordering the 1 required assembly to resolve your cranking no-start condition.
Manual Section: Fuel Injection PumpCannot find the correct fuel filter and feed pump part numbers for low RPM under load p. 18
Inspect the Fuel Line parts diagram on page 18. Identify the correct fuel oil filter, fuel strainer, and feed pump part numbers. Cross-reference the taper valve and fuel pipe assemblies with your specific machine serial number to ensure you order the exact matches.
Manual Section: Fuel LineTrying to locate the exact governor spring and control shaft components for unstable running p. 15
Review the Governer exploded view on page 15. Match your specific governor weight assembly, control shaft, and governor spring to the illustrated items. Note the required quantities for the 1 solenoid and angleich assembly before submitting your final parts order for the repair.
Manual Section: GovernerNeed complete gasket set and seal washer part numbers for hard starting after service p. 21
Examine the Gasket Set components list on page 21. Locate the exact part numbers for the cylinder head gasket, O-rings, and seal washers. Verify compatibility with the Cylinder Head & Bonnet diagrams on page 4 to prevent ordering incorrect parts for the 3 cylinders.
Manual Section: Gasket SetFrequently Asked Questions
What are the replacement specifications for fuel filter?
The fuel filter assembly for the Yanmar 3TNE78A-TBY is identified by part number 129053-55620. It is listed as "FILTER ASSY, FUEL OIL" in the fuel line diagram, providing the specific part for replacement.
What are the replacement specifications for fuel injection pump?
The fuel injection pump assembly for the Yanmar 3TNE78A-TBY is part number 719911-51380, listed as "PUMP ASSY, F. INJEC.". This specific part number is provided for replacement purposes within the fuel injection pump section.
How do you fix need to identify fuel injection pump components for Yanmar 3TNE78A-TBY engine that cranks but will not start?
Check the Fuel Injection Pump exploded view on page 13. Locate the specific plunger, tappet, and delivery valve assemblies for your exact model. Verify the part numbers for the control rack before ordering the 1 required assembly to resolve your cranking no-start condition.
How do you fix cannot find the correct fuel filter and feed pump part numbers for low RPM under load?
Inspect the Fuel Line parts diagram on page 18. Identify the correct fuel oil filter, fuel strainer, and feed pump part numbers. Cross-reference the taper valve and fuel pipe assemblies with your specific machine serial number to ensure you order the exact matches.
Is this Yanmar 3TNE78A-TBY, TB25FR Parts Catalog a digital download?
Instant PDF download. You get the full 25-page searchable Parts Catalog immediately after payment. Open it on your laptop, tablet, or phone right in the shop.
Are there any print restrictions on this manual?
Yes. The PDF has no DRM restrictions, so print any page or section you need for your shop. Works with any standard printer.
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