Description

Yanmar 3TNA72L-UTB Technical Manual – Factory Parts Breakdown

If you are tearing into a Yanmar 3TNA72L-UTB and realize you don’t have the correct main bearing part number, you are looking at a half‑day of cross‑referencing and praying. That is why you need the real OEM print. This 70-page Technical Manual is the Yanmar factory parts listing – not an aftermarket summary. It shows you exactly which bolt goes where and what plug seals the gear housing. I have seen guys order a cylinder head gasket based on a generic number and end up with a paper‑thin gasket that blows at startup. Page 2 lists the head gasket as 119610‑01340. That is the one you need.

Cylinder Block Parts: What Page 2 Tells You

The cylinder block assembly on page 2 breaks down every fastener and bearing. Fourteen cylinder head bolts, part number 119620‑01200. Four main bearings standard size, plus an undersize set (US=0.25) if your crank journal is ground. The thrust bearing set includes two pieces – part 119620‑02930. The camshaft bush is listed as 119620‑02410. Without this page, you are guessing on the number of thrust bearing halves. With it, you order the right parts the first time. No return trips to the dealer.

Gear Housing Assembly: O‑Rings and Seals

Turn to page 4 and you get the gear housing. The oil seal is HTC456208 (part 119620‑01800). Two O‑rings 1A P‑12.0 (24311‑000120). The knock pipe assembly (119660‑01911) uses four pieces. Home mechanics often miss the shim set (119620‑01950) behind the gear housing cover. If your gear lash is off, you need those shims. This manual shows the stack‑up. Also note the bracket, generator (119640‑77250) – that bolt pattern is unique. Use the chart to verify your M6x16 and M6x30 plated bolts. Don’t mix them up; the lengths matter for the generator mount.

Does This Manual Cover the Fuel Injection Pump?

No. The table of contents (not in our OCR excerpt) focuses on the short block and gear train. If you need pump timing or injector nozzle specs, you want the Yanmar service manual, not this parts catalog. But if your pump leaks at the drive gear, the relevant O‑ring and seal are listed in the gear housing section. For rebuild‑level work on the injection side, pair this with the service manual. For ordering the seal kit, this manual gives you the factory numbers.

3 Reasons to Use the Factory Parts List

First, the part numbers are genuine Yanmar – not a cross‑reference from a third‑party catalog. Second, the exploded views save you ten minutes per sub‑assembly. Third, the quantities are verified: page 2 calls for 8 bolts on the main bearing caps, 2 thrust bearings, 14 cylinder head bolts. One wrong number and you have an imbalance. Aftermarket catalogs often list 12 head bolts or skip the undersized mains. This is the OEM document. Use it and your engine will hold torque.

Order the Right Main Bearings at Home

If you are a DIY mechanic with a dial bore gauge, you can measure your main journals and then order standard or US=0.25 bearings directly from the manual. Part 719620‑02870 is the US set. Standard is 719620‑02800. No middleman looking up a confusing chart. The manual also tells you the (JP) part numbers if you need to order from Japan. That level of detail is why I keep a copy at my shop. I have had apprentices try to use generic bearing sets and they end up with oil pressure problems. Stick to the factory print.

For related manuals, consider the Ammann Yanmar B15-37, B17-3, B18 Technical Manual – OEM Factory Specs or the Yanmar 2TE67L-BV, SV08-1 Technical Manual – 58-Page Factory Spec Guide. If your application uses a Manual Transmission and you need gear train specs, the Yanmar EF-494T 2011 Technical Manual – Factory Torque Specs could also be relevant. For general transmission theory, refer to the article on Manual Transmission.

FAQ

Does this manual list torque values for the head bolts?

No. This is a parts catalog, not a service manual. Torque values are not included. You still need the Yanmar service manual for assembly specifications.

Can I rebuild the complete lower end using only this 70‑page manual?

If you have the tools and the service manual for clearances, yes. This manual gives you every part number for the cylinder block and gear housing – main bearings, thrust bearings, oil seal, shim set, cylinder head bolts, even the plug PT1/4 (124160‑01910). It shows you the exploded views so you know the order of assembly. But it does not include step‑by‑step instructions like a repair manual. For a full rebuild, pair it with the Yanmar service manual (sold separately). For ordering the correct parts and verifying you have them all, this is all you need. The page 2 list alone has saved me from ordering the wrong head gasket twice.

If you are working on a Yanmar 3TNA72L-UTB and need factory part numbers to get the job done right, stop guessing. Access the Factory Manual from AutoRepairManuals and get the OEM parts breakdown you need.