This 34-page Yanmar 3TNA72L-UBA parts catalog pdf (OEM #Y00B4102) breaks down the complete cylinder block, fuel injection device, and governor assemblies for your 3TNA72L-UBA/B engine. Inside, you get detailed exploded view diagrams paired with factory part numbers for every single component, from the flywheel housing to the starting motor. Open to the fuel system section to find clear illustrations of the delivery valves, plungers, and complete fuel feed pump breakdowns, making component identification fast and accurate. Verify your main bearing undersize at 0.25 before submitting an order, and confirm you need the 36.5 V-belt for the cooling water pump assembly. Stop buying the wrong replacement parts based on internet guesswork. Grab this bookmarked file, pull up the exact schematic on your phone in the shop, and get your parts order right the first time.
What's Inside This Yanmar 3TNA72L-UBA, 3TNA72L-UBA/B Parts Manual
| System | Pages | Key Topics |
|---|---|---|
| Engine | 1-2 | Figure 1 Cylinder Block, Figure 2 Gear Housing, Figure 3 Flywheel Housing & Oil Sump, Figure 4 Cylinder Head & Bonnet, Figure 5 Suction Manifold & Air Cleaner |
| Cylinder Block | 3-4 | Parts List for Figure 2 Gear Housing (Housing Assy, Gear, Plug 10X14, Stud M 8X 22, Spring Pin 4X10, Cover Assy, Housing, Seal Htc456208, Oil, Pipe, Knock, Shim Set, Shim Pack, Nut W/Washer 8, O-Ring 1A P 12.0, Bolt M 6X 16 Plated, Bolt M 6X 30 Plated, Bolt M 6X 60 Plated, Bolt M 6X 80 Plated, Cover, Gasket, Pump Cover, Stud M6X12, Cap, Lub.Oil Supply, O-Ring 1A P-32.0, Nut M 6, Blind, O-Ring 1A S-24.0, Bolt M 6X 18 Plated) |
| Gear Housing | 5-6 | Parts List for Figure 3 Flywheel Housing & Oil Sump (Sump Assy, Lub. Oil, Plug M22, Drain Plug M22, O-Ring 1A S-24.0, Seal Washer 22S, Spacer, Oil Sump, Bolt M 6X 12 Plated, Bolt M 6X 45 Plated, Parallel Pin 6X10, Case Assy, Oil Seal, Seal, Oil, Bolt M 6X 22 Plated, Parallel Pin 8X16, Bolt M 10X 28, Cap, Flywheel Cover, Bolt M10X25) |
| Flywheel Housing & Oil Sump | 7-8 | Parts List for Figure 4 Cylinder Head & Bonnet (Head Assy, Cylinder, Plug Pt1/4, Plug 5X 8, Plug 40, Valve, Suction, Exhaust, Spring, Retainer, Cotter, Cotter 7, Seal, Valve Stem, Cap, Spring Pin 6X12, Protector, Nozzle, Gasket, Guide, Lifter, Engine, Bolt M 8X 14 Plated, Bolt M 6X 12 Plated, Support Assy, Arm, Shaft Assy, Rocker, Arm Assy, Screw, Lock Nut M 6 Plated, Support, Rocker Arm, Circlip 12, Screw M 5X16, Stud, Bolt M 8X 45 Plated, Nut M 8, Knob, Bonnet Assy, Head, Joint, Plate, Shelter, Spring Washer 5, Screw M 5X 10, Bonnet, Lub.Oil Supply, O-Ring 1A P-32.0, Pipe 12X 700, O-Ring 1A P 12.0, Plug, Glow, Connector, Glow Plug) |
| Cylinder Head & Bonnet | 9-10 | Parts List for Figure 5 Suction Manifold & Air Cleaner (Support, Air Cleaner, Felt, Support, Case, Element, Bolt, Wing, Washer, Dust Pan, Retainer, Pipe, Air Intake, Clamp 60, Bolt M 8X 20, Nut M 8, Manifold, Gasket, Int.Manifold, Bolt M 6X 20 Plated) |
| Suction Manifold & Air Cleaner | 11-12 | Parts List for Figure 6 Exhaust Manifold & Silencer (Gasket, Silencer, Gasket, Stay, Bolt M 8X 20, Exh.Manifold, Nut W/Washer 8, Bolt M 8X 40 Plated, Stud M 8X 22 Plated, Stud M 8X 55 Plated) |
| Exhaust Manifold & Silencer | 13-14 | Parts List for Figure 7 Camshaft & Driving Gear (Camshaft Assy, Key 4X 12, Bearing, Thrust, Rod, Push, Tappet, Fuel Cam., Cam Assy, F.I. Pump, Ball Bearing 6303U, Ball Bearing, Bolt M 6X 16 Plated, Screw M 8X 10, Retainer, Idle Gear, Shaft, Gear W/Bush, Idle, Bush, Circlip 20, Bolt M 6X 12 Plated) |
| Camshaft & Driving Gear | 15-16 | Parts List for Figure 8 Crankshaft & Piston (Crankshaft Assy, Gear, Crankshaft, Crankgear, Key 4X 12, Parallel Pin 8X16, V-Pulley, Bolt M12X1.25, Flange, Washer, Bolt, Flywheel, Flywheel Assy, Ring, Piston W/Rings, Ring Set, Pin, Piston, Circlip 21, Piston W/Ring Os=.25, Ring Set 0.S=0.25, Ring Set O.S=0.25, Rod Assy, Connecting, Rod, Bearing, Crankpin, Bush, Piston Pin, Pin U.S=0.25, Piston W/Ring Os=0.5, Ring Set O.S=0.5) |
| Crankshaft & Piston | 17-18 | Parts List for Figure 9 Lub. Oil System (Pump Assy, Lub. Oil, Gasket, L.O.Pump, Bolt M 6X 20, Dipstick, Guide, Bracket, Oil Filter, Filter, O-Ring, L.O.Strainer, Valve Assy, Oil Press, Nut, O-Ring 1A P-16.0, Bolt M 8X 20 Plated, Pipe Assy, Lub.Oil, O-Ring 1A P 12.0, Bolt M 6X 10 Plated, Switch, Oil Pressure) |
| Lubrication Oil System | 19-20 | Parts List for Figure 10 Cooling Water System (Pump Assy, C. Water, Pump Assy, Cw, O-Ring, Plug Pt3/8, Screw, Gasket, C.W. Pump, V-Belt Fm=36.5, V-Pulley, Bolt M 6X 25, Bolt M 8X 45 Plated, Plug M16, Switch, Thermo(110Bc, Gasket 16, Cover, Thermostat, Thermo., Thermostat (71Bc, Bolt M 8X 20 Plated, Fan D310, Spacer) |
| Cooling Water System | 21-22 | Parts List for Figure 11 Fuel Injection Device (Pump Assy, F.Inject., Plunger W/Barrel, Retainer, Spring, Plunger, Shim Pack, Valve W/Seat, Deliv., Deliv. Valve, Holder, Gasket, Delivery, O-Ring, Guide, Pin, Rack, Pinion, Plate, Screw, Tappet Assy, Washer 4, Polished, Spring Washer 4, Screw M 4X 8, Screw M 4X 10, Valve Assy, F.Inject, Nozzle Assy, Nut, Valve W/Case, Valve, Seat, Nozzle Spring, Spacer, Valve Stop, O-Ring S10, Inj. Pipe, Bolt M 4X 12, Bolt M4X14, Hex.Sckt., Pipe, Fuel Inject, Pipe Assy, Fuel Over, Clamp 8, 6, Joint, Fuel Return, Over Flow Pipe, Bolt 8, Pipe Joint, Gasket 8, Gasket 14, Round, Clamp 12, Fuel Oil, Bend Assy, Bend, Return) |
| Fuel Injection Device | 23-24 | Parts List for Figure 12 Fuel Pipe (Gasket, F.Feed Pump, Gasket, Pump, Feed, Pump Assy, Fuel Feed, Bolt M 6X 20, Strainer Assy, F.O., Valve, Taper, Spring, Taper Valve, Lever, Cup, Strainer, O-Ring, Ring, Retaining, Element, Fuel, Screw M 4, O-Ring 1A P-10A, Clamp 8, Cap, Bolt W/Washer M8X 70, Joint 8, Pipe, Clamp 12, Pipe Assy, Fuel Oil, Joint 12, Bolt, Pipe Joint, Gasket 12, Bolt 12, Gasket 8, Seal Washer 8S) |
| Fuel Pipe | 25-26 | Parts List for Figure 13 Governor (O-Ring S6, Case, Governor, Gasket, Gov. Case, Cover, Governor Case, Link L=88.8(No Color, Link L=88.6, Link L=89.0, Weight Assy, Gov., Nut, Governor Weight, Sleeve, Spacer Assy, Shaft, Governor Lever, Lever Assy, Shim Set, Needle Bearing Fj810, Shifter, P.T.O., Spring, Starting, Washer 4, Circlip E- 4, Spring Pin 2X 4, Spring Pin 3X14, Retainer, Spring Pin 4X10, Snap Pin 4, Snap Pin 6, Bolt M 6X 70 Plated, Bolt M 5X 10 Plated, Angleich Assy, O-Ring 1A S-7.0, Shaft Assy, Bolt M 6X 10 Plated, Hook, Nut W/Washer 8, Regulator, Handle, Screw, Stop, Torque Spring Assy, Lock Nut M12, Lock Nut M12 Plated, Cap, Seal Washer 12S, Lead, Lock Nut M 6, Adjust, Wire 0.6, Seal Washer 6, Seal Waser 6, Plug) |
| Governor | 27-28 | Parts List for Figure 14 Starting Motor (Starter 12V-1.0W, Retainer, Yoke Assy, Armature Assy, Bearing, Ball Bearing, Clutch, Starter, Nut, Pinion, Shaft, Ring, Spring, Coil, Clutch Assy, Roller, Housing, Frame Assy, Holder Assy, Brush, Switch, Magnetic, Gasket, Bush, Cover, Plate, Plunger, Bolt W/Washer, Washer, Bolt, O-Ring, Screw W/Washer, Ball, Bolt M12X 25 Plated) |
| Starting Motor | 29-30 | Parts List for Figure 15 Generator (Washer, Spring, Collar, Washer 10, Nut, Plate Assy, Clamp, Stator, Coupler, Screw, Flywheel Assy, Adjuster, Belt, Bolt M 8X 25, Bolt M 8X 16 Plated, Bolt M10X 30 Plated) |
| Generator | 31-32 | Parts List for Figure 16 Tool & Gasket Set (Flex Horn, Gasket, Cyl. Head, Bonnet, O-Ring 1A P 12.0, Int.Manifold, Silencer, Exh.Manifold, C.W. Pump, O-Ring 1A P-32.0, O-Ring 1A S-24.0, Seal Washer 22S, Liquid) |
| Tool & Gasket Set Optional | 33-34 | Overview, Parts List, Brush, Gasket, Liquid, Cylinder Head, Rocker Cover, Oil Pan |
Every system also includes overview.
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Main Bearing Undersize | 0.25 (unit not specified) | p. 2 |
| Piston W/Ring Oversize | 0.25 (unit not specified) | p. 16 |
| Ring Set Oversize | 0.25 (unit not specified) | p. 16 |
| Bearing Pin Undersize | 0.25 (unit not specified) | p. 16 |
| V-Belt FM Length | 36.5 (unit not specified) | p. 20 |
| Fuel Pipe Diameter x Length | 12mm x 400mm | p. 24 |
| Governor Link Length (No Color) | 88.8 (unit not specified) | p. 26 |
| Governor Link Length (White) | 88.6 (unit not specified) | p. 26 |
| Starter Motor Rating | 12V-1.0W | p. 28 |
Yanmar 3TNA72L-UBA, 3TNA72L-UBA/B Common Problems This Manual Covers
Yanmar 3TNA72L-UBA engine starts poorly or will not crank over in cold weather conditions p. 29
Check the exploded view on page 29 for the starting motor components. Locate the 12V-1.0W starter assembly specification on page 28 to find the correct replacement part number. Verify the armature assembly and magnetic switch match your specific serial number block.
Manual Section: Starting MotorEngine overheats rapidly under load and the temperature gauge fluctuates wildly during normal operation p. 21
Inspect the cooling water system parts diagram on page 21. Find the exact part number for the V-belt, ensuring you select the one with a 36.5 length specification from page 20. Cross-reference the water pump assembly and gasket numbers before ordering replacement parts.
Manual Section: Cooling Water SystemSevere metal debris in the oil pan and low compression across all engine cylinders p. 17
Review the crankshaft and piston parts list on page 17. Identify the correct part numbers for the 0.25 oversize piston with rings listed on page 16. Match the connecting rod bearings and piston pins precisely to your engine series to ensure proper clearances.
Manual Section: Crankshaft & PistonEngine surges at idle or fails to maintain a steady RPM under changing loads p. 27
Examine the governor parts breakdown on page 27. Find the specific part number for the governor link, noting the 88.8 length specification from page 26 for the uncolored variant. Check the adjacent governor weight assembly and spring part numbers to complete your order list.
Manual Section: GovernorFrequently Asked Questions
How do you fix 3TNA72L-UBA engine starts poorly or will not crank over in cold weather conditions?
Check the exploded view on page 29 for the starting motor components. Locate the 12V-1.0W starter assembly specification on page 28 to find the correct replacement part number. Verify the armature assembly and magnetic switch match your specific serial number block.
How do you fix engine overheats rapidly under load and the temperature gauge fluctuates wildly during normal operation?
Inspect the cooling water system parts diagram on page 21. Find the exact part number for the V-belt, ensuring you select the one with a 36.5 length specification from page 20. Cross-reference the water pump assembly and gasket numbers before ordering replacement parts.
How do you fix severe metal debris in the oil pan and low compression across all engine cylinders?
Review the crankshaft and piston parts list on page 17. Identify the correct part numbers for the 0.25 oversize piston with rings listed on page 16. Match the connecting rod bearings and piston pins precisely to your engine series to ensure proper clearances.
How do you fix engine surges at idle or fails to maintain a steady RPM under changing loads?
Examine the governor parts breakdown on page 27. Find the specific part number for the governor link, noting the 88.8 length specification from page 26 for the uncolored variant. Check the adjacent governor weight assembly and spring part numbers to complete your order list.
Document Quality
This document is a scanned PDF, featuring both OCR-processed text pages and image-based diagrams. You can search and copy text from the parts lists and descriptive sections, which are crisp and easy to read. All diagrams and illustrations are clear raster images, with labels consistently readable at various zoom levels. The pages are clean, free from scan artifacts, stains, or skewed content. There are no notable blank or filler pages throughout the document.
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