Need factory part numbers for your Yanmar 4TN78TL-DB, 4TN78TL-RB, or 4TN78TL-DBVM engine? This 63-page parts catalog (OEM #Y00B3631) covers all three variants, including the K2094 configuration, with every component mapped to its Yanmar part number. Inside: exploded views across 30 systems, from cylinder block and turbocharger assembly to fuel injection pump, governor, and starting motor, each indexed with factory part numbers and cross-references. You get component-level breakdowns throughout: rocker arms and valve springs in the cylinder head section, plunger-and-barrel detail in the fuel injection pump pages, and Yanmar references for every gasket, seal, and bearing in the engine. The A-38 V-belt, the 3x10 mm spring pin in the block, and the 7x14 mm camshaft key are all called out with full OEM part numbers. Stop guessing off worn tags. Bookmarked by system and searchable by keyword, so you can jump to the fuel strainer or pull up the cooling water section on your phone right at the parts counter.
What's Inside This Yanmar 4TN78TL-DB / RB / DBVM (K2094) Parts Manual
| System | Pages | Key Topics |
|---|---|---|
| Cylinder Block | 2-3 | Cylinder Block Assy, Main Bearing, Thrust Bearing, Camshaft Bush, Cylinder Head Gasket, Cylinder Liner, Cylinder Sleeve, Check Valve Assy |
| Gear Housing | 4-5 | Gears w/ Seal Housing, Oil Seal, Lub. Oil Supply Cap, Gear Housing Flange, Gears Housing Flange, Hydraulic Oil Pump Cover, Hydraulic Oil Pump Gasket, Gasket |
| Flywheel Housing | 6-7 | Flywheel Cover Cap, Pin, Bolt |
| Lub.Oil Sump | 8-9 | Lub. Oil Sump Assy, Oil Sump, Knock Pipe, Oil Sump Cover Gasket |
| Oil Seal Housing | 10-11 | Oil Seal Case Assy, Oil Seal, Oil Seal Case Gasket, Pin |
| Bonnet | 12-13 | Bonnet Assy, Bonnet Gasket, Breather Cover Assy, Shelter Plate, Breather Baffle, Lub. Oil Supply Cap, Knob, Breather Pipe |
| Gear Housing Cover | 14-15 | Hydraulic Oil Pump Cover, Cover, Hydraulic Oil Pump Gasket, Round Gasket 8, Blind Cover |
| Cylinder Head | 16-17 | Cylinder Head Assy, Valve Guide, Intake Valve, Exhaust Valve, Valve Spring, Spring Retainer, Valve Stem Seal, Valve Cap |
| Air Cleaner | 18-19 | Intake Pipe, Air Cleaner Assy, Cover, Air Cleaner Element, Indicator, Unloader Valve, Air Cleaner Bracket, Rubber Seat |
| Exhaust Manifold | 20-21 | Exhaust Manifold Gasket, Bolt, Stud |
| Camshaft | 22-23 | Camshaft Assy, Camshaft Gear, Thrust Bearing, Tappet, Push Rod |
| Turbocharger | 24-25 | RHB31 Turbo Charger, Heat Protector, Hose, Turbo Rotor Assy, Blower Housing Assy, Turbo Housing Assy, Housing Assy, Control Assy |
| Crankshaft & Flywheel | 26-27 | Crankshaft Assy, Crankshaft Gear, V-pulley, Flywheel Assy, Ring Gear |
| Piston | 28-29 | Piston Assy, Ring Set, Piston w/ Ring 0.25, Pin |
| Connecting Rod | 30-31 | Connecting Rod Assy, Piston Pin Bush, Bolt, Pin |
| Idle Gear | 32-33 | Idle Shaft, Idle Gear Shaft, Idle Gear w/ Bush, Gear w/ Bush, Idle Gear Bush |
| Lub. Oil System | 34-35 | Lub. Oil Pump Assy, Lub. Oil Pump Gasket, Lub. Oil Cooler, Lub. Oil Dipstick, Dipstick Guide, Oil Strainer Gasket, Gasket, Oil Inlet Pipe |
| Lub.Oil Line | 36-37 | Check Valve, Oil Pressure Switch, Lub. Oil Pipe Assy, Round Gasket 10, Retainer 8X 8, Retainer, Pipe Joint PT3/8, Lub. Oil Return Pipe |
| Cooling Water System | 38-39 | Cooling Water Pump Assy, Cooling Water Pump Gasket, Elbow, Elbow PT1/4, V-belt, V-pulley, Cooling Fan, Spacer |
| Fuel Injection Pump | 40-42 | Pump w/ Governor & Feed Pump, Camshaft, Thrust Ball Bearing, Bearing Retainer, Plunger w/ Barrel, Retainer A, Plunger Spring Shoe, Plunger Spring |
| Fuel Injection Valve | 43-44 | Fuel Injection Valve Assy, Fuel Injection Nozzle Assy, Nozzle Holder Assy, Nozzle Spring, Nozzle Spring Seat, Stop Plate |
| Fuel Injection Pipe | 45-46 | Retainer, Bolt |
| Fuel Strainer & Fuel Line | 47-48 | Pipe Joint 12, Gasket 12, Fuel Pipe, Fuel Strainer Assy, Taper Valve, Taper Valve Spring, Lever, Strainer Cup |
| Fuel Return Line | 49-50 | Pipe Joint 12, Joint, Fuel Pipe, Fuel Return Pipe, Cap, Check Valve Assy, Round Gasket 12 |
| Governor | 51-52 | Governor Case, Governor Case Gasket, Governor Case Cover, Case Cover Gasket, Link 0, Control Lever, Governor Lever Shaft, Governor Lever Assy |
| Starting Motor | 53-54 | Starter, Pinion Stopper Set, Pinion Stopper Clip, Field Coil Assy, Pore Core Screw Set, Brush, Rear Cover Assy, Rear Cover Metal |
| Generator | 55-56 | Rotor Assy, Spacer, Stator Assy, Rear Cover Assy, Regulator Brush Assy, Brush Assy, Regulator Assy |
| Magnetic Relay | 57-58 | Earth Cord, Cord, Bolt |
| Tropics & Desert Type (Option) | 59-60 | Dust Filter, Air Cleaner Assy, Outer Element, Cleaner Body, Air Cleaner Cup, Baffle, Inner Element, Unloader Valve |
| Gasket Set & Tool (Option) | 61-63 | Gasket Set, Cylinder Head Gasket, Hydraulic Oil Pump Gasket, Oil Sump Cover Gasket, Oil Seal Case Gasket, Bonnet Gasket, Suction Manifold Gasket, Exhaust Manifold Gasket |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Spring Pin Dimensions | 3x10 mm | p. 2 |
| Key Dimensions | 7x14 mm | p. 22 |
| V-Belt Type | A-38 | p. 38 |
Yanmar 4TN78TL-DB / RB / DBVM (K2094) Common Problems This Manual Covers
Yanmar 4TN78TL-DBVM engine runs hot and needs a replacement cooling fan belt part number p. 38
Inspect the Cooling Water System exploded view on page 38. Locate the fan drive components to identify the correct V-belt. Verify whether your specific setup requires the A-38 or A-39 type V-belt. Cross-reference the assigned item number with the parts list to order the exact replacement.
Manual Section: Cooling Water SystemNeed the correct woodruff key part number for the camshaft gear after experiencing timing slip p. 22
Check the Camshaft assembly breakdown on page 22. Find the drive gear section to locate the exact 7x14 mm key required for the shaft. Match the illustration number to the parts table to ensure you order the proper key and associated thrust bearings.
Manual Section: CamshaftRebuilding the short block and cannot locate the correct alignment dowel or spring pin part numbers p. 2
Review the Cylinder Block Parts Number List on page 2. Identify the block assembly diagram to find the exact 3x10 mm spring pin used for component alignment. Record the part number from the index to ensure proper mating of the gear housing and block during reassembly.
Manual Section: Cylinder BlockFrequently Asked Questions
What are the replacement specifications for filters?
The manual lists several filters with their part numbers. For fuel, there is an "ELEMENT, FUEL" (part number 129100-55650). Air filters include "FILTER, DUST" (part number 129503-03210) and "ELEMENT, OUTER" (part number 121420-12511). For the lubrication system, a "FILTER 90X80L" (part number 129150-35150) is specified. The manual does not provide replacement intervals or detailed specifications beyond these part numbers and descriptions.
What are the replacement specifications for valves?
The manual provides part numbers for various valves. For the cylinder head, "VALVE, INTAKE" (part number 129100-11100) and "VALVE, EXHAUST" (part number 129100-11130) are listed. Fuel injection components include "VALVE ASSY, F.INJECT" (part number 729503-53100). In the lubrication system, a "VALVE ASSY, BY-PASS" (part number 129553-35500) is specified.
What is the correct V-belt part number for the 4TN78TL-DBVM cooling fan?
Inspect the Cooling Water System exploded view on page 38. Locate the fan drive components to identify the correct V-belt. Verify whether your specific setup requires the A-38 or A-39 type V-belt. Cross-reference the assigned item number with the parts list to order the exact replacement.
What is the woodruff key part number for the camshaft gear?
Check the Camshaft assembly breakdown on page 22. Find the drive gear section to locate the exact 7x14 mm key required for the shaft. Match the illustration number to the parts table to ensure you order the proper key and associated thrust bearings.
Can I download or print this parts catalog?
Yes. This is a PDF parts catalog — you can download it to your device and print any pages you need at the shop. It is searchable by keyword, so you can jump directly to the fuel strainer section or pull up the cooling water pages without scrolling through all 63 pages.
Document Quality
This document is a scanned PDF with an accurate OCR layer, allowing you to search and copy the full text content. The text throughout the document is crisp and easy to read, with no blurriness or fading. Diagrams are clear line drawings, and all labels within them are perfectly readable. The pages are clean and free from any scan artifacts, stains, or skewed content. There are no notable blank or filler pages, ensuring all content is present and relevant.
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