Part of the Yanmar Parts Manuals.
A 3TNC78L-RKAH that cranks but will not fire almost always comes down to the fuel side, and the injection pump pages in this catalog break that assembly into plunger with barrel, delivery valve with seat, and tappet assembly, each carried under its own Yanmar part number. Guessing at those numbers is expensive: order the wrong nozzle assembly or bearing and you pay for the part twice and do the teardown twice.
This is Yanmar publication Y00B4192, the parts catalog for the 3TNC78L-RKAH (V2) diesel engine, 37 pages of exploded views spanning cylinder block, cylinder head, crankshaft and pistons, camshaft and gears, lubrication and cooling systems, governor, engine stop device, starting motor, and generator. It also lists 0.25 oversize main and crankpin bearings plus oversize pistons and ring sets for rebuild work.
The PDF downloads instantly and prints clean, so the pages you need can sit beside the parts tray and get dirty while the engine is apart.
What's Inside This Parts Manual
| System | Pages | Key Topics |
|---|---|---|
| Cylinder Block | 3-4 | Gear Housing Assy, Oil Seal, Lub. Oil Supply Cap, Gears Housing Flange, Hydraulic Oil Pump Cover, Hydraulic Oil Pump Gasket, Gasket, Knock Pipe |
| Gear Housing | 5-6 | Flywheel Housing, Flywheel Cover Cap, Lub. Oil Sump Assy, Lub. Oil Sump Spacer, Oil Seal Case Assy, Oil Seal |
| Flywheel Housing & Lub. Oil Sump | 7-8 | Cylinder Head Assy, Suction Valve, Exhaust Valve, Valve Spring, Spring Retainer, Valve Stem Seal, Valve Cap, Rocker Support Assy |
| Cylinder Head & Bonnet | 9-10 | Suction Manifold Gasket, Gasket, Suction Manifold, Exhaust Manifold, Exhaust Manifold Gasket, Air Heater, Air Heater Gasket |
| Suction & Exhaust Manifold | 11-12 | Camshaft Assy, Camshaft Gear, Thrust Bearing, Tappet, Push Rod, Idle Gear Shaft, Gear W/ Bush, Idle Gear Bush |
| Camshaft & Driving Gear | 13-14 | Crankshaft Assy, Crankshaft Gear, Crankshaft V-Pulley, Flywheel W/ Gear, Flywheel W/ Ring Gear, Ring Gear, Piston W/ Rings, Ring Set |
| Crankshaft & Piston | 15-16 | Lub. Oil Pump Gasket, Oil Strainer Gasket, Gasket, Oil Inlet Pipe Assy, Strainer Bracket, Bracket Gasket, Filter 90X80L, Lub. Oil Pipe Assy |
| Lub. Oil System | 17-18 | Cooling Water Pump Assy, Cooling Water Pump Gasket, V-Belt, Cooling Water Pump V-Pulley, Fan D310, Thermo.cover Gasket, Gasket, Thermostat Gasket |
| Cooling Water System | 19-20 | Fuel Injection Pump Gear, Fuel I Pump Assy, Camshaft, Thrust Ball Bearing, Bearing Retainer, Plunger W/ Barrel, Retainer a, Plunger Spring Shoe |
| Fuel Injection Pump | 21-22 | Fuel Injection Valve Assy, Fuel Injection Nozzle Assy, Nozzle Holder Assy, Nozzle Spring, Nozzle Spring Seat, Stop Plate, Injection Pipe Retainer, Fuel Injection Pipe |
| Fuel Injection Device | 23-24 | Pipe Joint, Gasket, Fuel Pipe, Fuel Return Pipe, Joint, Cap, Check Valve Assy, Round Gasket |
| Fuel Line | 25-27 | Governor Case Gasket, Governor Case Cover, Case Cover Gasket, Link, Governor Weight Assy, Sleeve, Control Shaft Assy, Shaft Spacer |
| Governor | 28-29 | Stop Motor Assy, Stop Motor Spring, Snap Ring, Stop Motor Bracket |
| Engine Stop | 30-31 | Starter, Cover, Retainer, Clutch Kit, Pinion, Shaft, Ring, Coil Spring |
| Starting Motor | 32-33 | Generator, Rotor Assy, Bearing Cover, Drive Flame Assy, Plate, Rear Flame Assy, Cover, Crankshaft Pulley |
| Generator | 34-35 | Flex Horn, Gasket Set, Cylinder Head Gasket, Hydraulic Oil Pump Gasket, Bonnet Gasket, Valve Stem Seal, Nozzle Protector, Nozzle Seat |
| Tool & Gasket Set | 36-37 | Gasket, Cyl. Head, Suc. Manifold, Exh. Manifold, O-Ring, F.I. Pump |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Main Bearing Oversize | 0.25U.S | p. 2 |
| Crankpin Bearing Oversize | 0.25U.S | p. 14 |
| Piston w/Ring Oversize | 0.25 | p. 14 |
| Ring Set Oversize | 0.25 | p. 14 |
| V-Belt Type/Size | A-39 | p. 18 |
| Link Length (Mark 0) | 30 | p. 26 |
| Link Length (Mark 1) | 31 | p. 26 |
| Link Length (Mark 05) | 30.5 | p. 26 |
