Description

Yanmar 4TNC88 Service Manual – Factory Specs Only

If you have wasted an afternoon chasing a stripped plug thread or a leaking oil seal because some aftermarket manual guessed the part number, you know why this Yanmar 4TNC88 Service Manual belongs on your bench. Thirty-nine pages of factory-sourced data – no editorial shortcuts, no generic illustrations. Every part number, every plug size, every bolt length came straight from Yanmar’s engineering drawings. That matters when you are holding a M8x16 plated bolt and the parts list on page 4 tells you exactly how many go where.

Engine Block Assembly and Parts Layout

Page 2 opens with the cylinder block assembly – part numbers 729407-01560 and 729407-01561 for the block itself, with a note that the second supersedes the first after engine serial 01169. This manual lists every plug: PT1/4, PT1/8, PT3/8, plus the 50mm and 12mm plugs and the eight 30mm plugs. Main bearing cap bolts are 129150-02020, and the US=0.25 oversize bearings carry their own part number (129150-02870). If you are rebuilding a 4TNC88 and need thrust bearings, the .25 oversize is listed as 129150-02940. That kind of specificity keeps you from ordering wrong parts.

Does This Manual Cover the Fuel Injection System?

Yes, but only peripherally. The gear housing section on page 4 includes the O-ring for the fuel injection pump (part 121850-51960) and the oil seal (129795-01800). The fuel pump itself is not disassembled here – you would need the separate injection pump service manual. What this gives you is the mounting hardware and the seal dimensions so you do not cross-thread a stud or over-torque the flange. The seal washer references (43400-500410 and its supersession 22190-080002) are also noted. Check the Manual Transmission section on Wikipedia if you need a primer on gearbox basics, but for the engine block, stay here.

39 Pages of Factory Parts Breakdown

Thirty-nine pages total, and every one is a parts catalog with exploded views. No torque value tables in this manual – it is a parts identification and assembly guide, not a repair procedure manual. The first four pages alone list over fifty line items for the cylinder block and gear housing. The “OS” (oversize) and “US” (undersize) markers are printed right next to the part numbers. When you see “E/# 01169” on the cylinder block assembly, that tells you the engine serial where the design changed. This is the kind of detail aftermarket CD‑ROMs leave out.

Gear Housing: Exploded View and Seal Locations

Page 4 covers the gear housing assembly – part 719810-01500. It shows the blind cover (121023-01550) and the two studs M8x22. Every bolt is dimensioned: M8x12, M8x16, M8x20, M8x45, M8x55, M8x85, each with a plated finish code. The O-rings are specified by standard 1A dash numbers: P-16.0, P-32.0, S-24.0. If you are replacing the gear housing gasket (non-asbestos, part 124240-01883), the parts list tells you it is an “A” type – asbestos-free. Do not guess the seal washer size; this manual gives you the exact dash number.

Verify Your Parts Against OEM Documentation

Aftermarket manuals often substitute “similar” plugs or omit the notation for when a part was superseded. This Yanmar 4TNC88 Service Manual prints the original part number and the supersession right there – for example, the seal washer changed from 43400-500410 to 22190-080002 at engine serial 02080. Use a digital caliper on your old parts, match the thread size and length, then order. The table on page 2 even separates the “N” (new) parts from the original. That level of traceability saves you a second trip to the dealer.

If you are working on related Yanmar models, check Ammann Yanmar ViO15-2A, ViO20, ViO25, ViO30, ViO35 2006 Service Manual OEM for compact excavator applications. For the larger mini-excavator lineup, the Ammann Yanmar Vi075-A, B7-Σ-A, SV100 2007 Service Manual | OEM Factory Specs covers the bigger engines. And if you need the B55W wheel loader manual, the Ammann Yanmar B55W Service Manual – 191 Pages of Factory Specs has the transmission and hydraulic data you won’t find here. For general transmission theory, Manual Transmission on Wikipedia is a solid reference.

Bottom line: this is a parts manual, not a step-by-step rebuild book. But if you are ordering gaskets, bearings, seals, or fasteners for a 4TNC88 engine, these 39 pages give you the factory‑verified part numbers. No guessing about plug thread sizes or whether a bolt is plated. Access the Factory Manual and keep your parts counter honest.

What is included in the cylinder block section?

Page 2 lists the cylinder block assembly, main bearings, bearing cap bolts, thrust bearings, camshaft bush, head studs, and all plugs with thread sizes. The US=0.25 main bearing and thrust bearing parts are also listed with their own part numbers.

Are parts numbers with ‘OS’ for oversize bearings listed?

Yes. The gear housing section shows oversize bearings? Actually no – the main bearing US=0.25 is undersize. The manual does not list OS bearings for the 4TNC88 in these pages; it only shows standard and US.

Does this manual include torque specifications?

No. This is a parts catalog, not a repair procedure manual. Torque values are not printed anywhere in the 39 pages.

Can I use this for the 4TNC88L-RB model?

Yes. The first page includes the code 4TNC88L-RB (B50-2). The parts list applies to that specific model variant.