Yanmar 4LH-TE, 4LH-HTE, 4LH-DTE, 4LH-STE Marine Diesel Engine (2000s) Service Manual (P/N A0A1030-1)

This Yanmar 4LH series service manual (P/N A0A1030-1) covers the 4LH-TE, 4LH-HTE, 4LH-DTE and 4LH-STE marine diesel engines. The original publication was printed in Japan.

Printable PDF and Wiring Diagram Detail

Search, navigation and small labels: Text search is not available for the technical chapters, and there are no embedded PDF bookmarks. Small wire-color and connection labels in the instrument-panel wiring diagrams require zooming.

The manual is supplied as one English-language, printable 398-page PDF. That total includes the cover, foreword, contents page, chapter dividers and 17 blank pages.

Engine, Injection and Marine Gear Service

These selected service topics are part of a wider contents list that also covers the optional rotary waste-oil pump and bilge pump/strainer.

• Engine internals: Cylinder-head and valve service, piston and piston-pin inspection, connecting-rod checks, crankshaft/main-bearing measurements, and camshaft, tappet and timing-gear data.

• Fuel injection: Fuel-system bleeding, injection-timing checks, VE and YPES-AL pump service, governor adjustment, nozzle testing and fault-finding tables.

• Turbochargers: IHI and KKK disassembly, inspection, reassembly, rotor-clearance checks, blower cleaning and troubleshooting for the covered engine variants.

• Cooling and lubrication: Sea-water-pump repair, heat-exchanger leakage tests, thermostat checks, lube-oil-pump inspection, oil-cooler testing and piston-cooling-nozzle inspection.

• Marine gear and controls: Reduction/reversing-gear teardown, clutch inspection, bearing and shim adjustment, plus optional remote-control installation and cable adjustment.

• Electrical diagnosis: Instrument-panel wiring diagrams, starter-motor inspection, alternator testing, warning-device checks and tachometer fault tracing.

Written for engineers engaged in service, inspection and maintenance, this manual assumes basic engine-service knowledge and omits explanations of work the reader is expected to know.

Engine Construction and Internal Repair

The basic engine chapter covers the cylinder block, liners and head assemblies, with step-by-step instructions for valve-seat correction and valve-guide replacement. Piston/liner matching marks, bearing clearances and wear limits support decisions about component reuse and replacement during engine repair.

Performance curves, flywheel dimensions and dimensional outlines supplement the component drawings.

Assembly details: The liner notes identify rust left on the block ledge as a cause of excessive liner projection. Valve-spring illustrations identify the smaller-pitch, yellow-painted end and its required orientation; the timing-gear section warns that excessive backlash can damage gears and disturb valve and injection timing.

Injection Pumps, Governors and Nozzles

The VE distributor-type equipment serves the TE and HTE engines, while the DTE and STE specifications identify YPES 4AL inline pumps. The cross-sectional view of the VE injection pump and the test-bench piping diagram explain pump construction and the measuring setup used for performance checks.

Pump work extends to plunger inspection, governor linkage, injection-volume adjustment and nozzle spray/leakage checks. Included model-specific pump calibration sheets are identified for the 4LH-HTE and 4LH-DTE; the test-bench procedures refer to the applicable individual test standards.

The troubleshooting tables connect starting problems, unstable output, knocking and exhaust smoke with possible fuel-system causes. These checks support fault isolation before the injection pump is removed.

Turbocharger Variants

The turbocharger chapter separates IHI RHC61/MY58 service for the TE, HTE and STE from the KKK unit used on the DTE. It includes component section views, inspection limits and boost-pressure checks.

The KKK instructions call for a dynamic balance check when rotating parts are reused, making specialist equipment relevant to this part of the repair scope.

Cooling and Lubrication Systems

Fresh-water and sea-water circuit diagrams show how the heat exchanger, air cooler, engine and marine gear cooling circuits connect. The sea-water pump has disassembly and reassembly coverage; the fresh-water pump is treated as a replacement assembly rather than an overhaul item.

Lubrication coverage distinguishes the pump arrangements and includes separate leakage tests for the oil and sea-water sides of the lube-oil cooler.

Marine Gear, Controls and Electrical Tests

The KM5A sectional view supports drive-cone, torque-limiter and shaft inspection. HSW630A1 coverage includes clutch-disc arrangement, bearing-preload adjustment and functional testing, while the remote-control chapter addresses throttle, shift and stop-cable connections.

Electrical diagrams distinguish B2, C/D and E instrument panels. Starter inspection includes armature and field-coil tests; alternator sections cover diode, rotor, stator and regulator checks, with charging-failure flowcharts and tachometer sender diagnosis.

Since working with high-pressure marine diesel components involves significant safety risks, a certified marine technician should always verify your final assembly and clearances prior to testing.

A Preview of Fastener, Valve and Cooling Data

The service data sheet lists main bearing cap bolt torque at 19–21 kg-m and connecting-rod bolt torque at 11.5–12.5 kg-m.

Cold valve-clearance data specify 0.1 mm at the intake, with exhaust settings of 0.3 mm for the TE/HTE/DTE and 0.5 mm for the STE. Cooling-capacity tables list 14 liters for the engine’s fresh-water circuit, with the sub tank listed separately.