Part of the Yanmar Parts Manuals.
Strip a Yanmar 4TN78TL down to the bare block and every liner, bearing shell, and gasket you pull off has a factory part number this catalog puts in front of you. Yanmar publication Y00B3631 covers the 4TN78TL-DBVM, 4TN78TL-DB, and 4TN78TL-RB, including the K2094 designation, across 63 pages of exploded views and numbered parts lists.
When the engine is in pieces on a stand and there is nobody at a parts counter to ask, guessing at an O-ring or oil seal is how a rebuild stalls for a week. Each of the 30 sections, from Cylinder Block and Cylinder Head through the Fuel Injection Pump to the Starting Motor and Generator, pairs a diagram with exact factory numbers so you order everything once.
Bookmarked sections take you from the part in your hand to its listing in a couple of clicks, whether this engine sits in a genset, a pump, a boat, or on your bench.
What's Inside This 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 |
