Yanmar 3TNV82A, 3TNV84, 3TNV84T, 3TNV88, 4TNV84, 4TNV84T, 4TNV88, 4TNV94L, 4TNV98, 4TNV98T, 4TNV106, and 4TNV106T Diesel Engine Service Manual (P/N M9961-02E050)

The Yanmar TNV Series Service Manual (document code M9961-02E050) covers the 3TNV and 4TNV direct-injection industrial diesel engines listed above, including both 2-valve and 4-valve cylinder head configurations. It is bundled with the YPD-MP2/YPD-MP4 Fuel Injection Equipment Service Manual (Literature No. M9961-03E070).

• Engine repair: Engine disassembly and reassembly, cylinder head and cylinder block inspection, valve seat correction, cylinder bore correction and valve guide replacement.

• Fuel injection: MP2/MP4 pump and governor overhaul, fuel injection timing calibration, nozzle pressure inspection and spray-pattern testing.

• Lubrication and cooling: Trochoid pump clearance inspection, oil-pressure checks, thermostat testing and water-pump assembly replacement.

• Turbochargers: Rotor inspection, turbocharger disassembly and reassembly, wastegate valve adjustment and fault diagnosis for the turbocharged models.

• Starting and charging: Starter motor servicing, alternator checks, engine wiring diagrams and electrical troubleshooting flowcharts.

Suited to diesel technicians familiar with precision engine measurement; internal injection-pump calibration also requires dedicated test-bench equipment.

Engine Variants and Internal Repair

Initial chapters break down engine nomenclature, cylinder bore and stroke combinations, and constant-load (CL) versus variable-load (VM) specifications. The Hyundai reference cover identifies mini-excavator and skid steer loader applications; this is an engine repair reference, with machine-specific service requiring the applicable Hyundai manual.

Cylinder head and gear train exploded views support the disassembly sections. Valve seat lapping, camshaft inspection, crankshaft bearing selection and piston-to-cylinder clearance checks extend the coverage into internal repair.

The four-valve rocker cover section warns that attached pipe seals can catch on the injection nozzles and be damaged during cover removal.

Maintenance, Diagnosis and Service Limits

Periodic inspection procedures cover routine checks and longer-term servicing. Water separator cleaning, fuel-system bleeding and V-belt tension inspection are covered alongside the manual's EPA/ARB emissions information.

The troubleshooting guide addresses starting failures, exhaust smoke, and cooling or lubrication anomalies. Compression tests and model-specific tables provide pressure limits, fluid capacities and main-bolt tightening torques, including fuel injection pump drive gear nut specifications.

Valve-clearance data distinguishes the 4TNV106 and 4TNV106T from the smaller engines, making the model-specific tables important when selecting adjustment specifications.

MP2/MP4 Injection Pump and Governor Service

The separate fuel injection manual covers internal pump work beyond engine-side removal and installation. Its Fuel Flow Diagram and governor section views accompany hydraulic-head, plunger and distribution-shaft overhaul, with speed/load timers, Cold Start Device (CSD) operation and torque-rise adjustment.

Pump calibration covers injection quantity and governor settings on a dedicated test bench. Listed bottom-clearance gauges differ by pump family: 158090-51800 for MP2 and 158090-51810 for MP4.

Pump troubleshooting starts with engine condition, fuel supply, nozzles and timing checks. That helps isolate faults outside the pump before unnecessary removal. A CSD repair warning explains that manually extracting the thermo-element piston leaves the unit unusable.

Turbocharger, Lubrication and Cooling Systems

Turbocharger chapters distinguish the RHB31, RHB51 and RHF5 units. They cover rotor end play, wastegate operation and troubleshooting for oil leakage, poor boost response and abnormal noise.

The Lubrication System Diagram shows oil circulation and model-dependent oil-cooler and piston-cooling arrangements. The cooling chapter specifies replacement of the water pump as a complete assembly.

Starter, Alternator and Engine Wiring

Starter servicing includes armature, field-coil, brush and magnetic-switch tests, with separate representative units for 4TNV94L/98 and 4TNV106/T engines. The alternator chapter documents a representative 40A unit, including output characteristics and charge-lamp fault diagnosis.

The Electric Wiring Diagram identifies starter, alternator, preheat and stop-solenoid circuits, wire colors and connectors. Working on heavy-duty diesel engines carries inherent safety risks; follow the manual's precautions for rotating machinery and electrical isolation during repair.

PDF Contents, Bookmarks and Wiring Detail

One printable, 280-page PDF contains the 213-page engine manual, the 66-page fuel injection manual and one Hyundai reference cover; manual covers, front matter and the supplement's revision-history sheet are already included in those totals. Text search is unavailable; 14 bookmarks link to the opening cover and main engine chapters, with no bookmarks for the fuel injection supplement. Small wire and connector labels in the engine wiring diagram require zooming.