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4JH-HT Marine

Yanmar 4JH-HT · 4JH-HT family: specifications, its industrial/tractor base engine, cross-referenced parts and where to buy them.

🚜 Base engine confirmed

The Yanmar 4JH-HT is a Yanmar marine diesel in the 4JH family. Yanmar designs and sells both marine and industrial diesels; internal service parts for this family are listed in the 4JH parts book and often sell cheaper through industrial/agricultural channels than under marine dealer pricing. — Yanmar OEM parts catalog in-repo (brands/yanmar/data/extracted/catalogs.csv)

66 hp48.5 kW
1644 ccdisplacement
78×86 mmbore × stroke
4-cylcylinders
1985–1989year range (approx)
Turboaspiration

high turbo; ~66mhp mapped from Marine Specialists JH-THE; bore confirmed; hp=verify

📋 Full specifications 🚜 Industrial / tractor base 🔧 Aftermarket 58
Cheaper-part coverage · 4/8
🚜 Base engine ✓🌀 Impeller ✓💧 Raw-water pump🛢️ Oil filter⛽ Fuel filter🌡️ Thermostat ✓➰ Belt ✓⚓ Anode

A ✓ means at least one cheaper channel — aftermarket, the tractor/industrial base engine, or a standard component — exists for this engine in that category.

Parts by section · 49 assemblies

The exploded parts diagrams for the 4JH-HT, grouped by system. Open a figure for its callout part numbers and per-variant quantities.

Camshaft & timing gears

Fig 2 — GEARS HOUSINGFig 15 — CAMSHAFT

Controls

Fig 40 — REMOTE CONTROL DEVICE

Cooling – fresh water

Fig 25 — COOLING FRESH WATER PUMPFig 26 — COOLING FRESH WATER COOLER

Cooling – sea water

Fig 24 — COOLING SEA WATER PUMPFig 27 — KINGSTON COCKFig 49 — SEA WATER FILTER

Crankshaft & flywheel

Fig 3 — FLYWHEEL HOUSINGFig 18 — CRANKSHAFT

Cylinder block

Fig 1 — CYLINDER BLOCK

Cylinder head & valves

Fig 7 — CYLINDER HEADFig 9 — BONNET

Electrical & instruments

Fig 38 — ENGINE STOP DEVICEFig 39 — COLD START DEVICEFig 41 — STARTING MOTORFig 43 — WIRE HARNESS & SENSORFig 44 — INSTRUMENT PANEL (B TYPE)Fig 48 — ELECTRIC BILGE PUMP(12V)Fig 51 — INSTRUMENT PANEL (C TYPE)Fig 55 — INSTRUMENT PANEL(NEW B-4 TYPE)Fig 56 — INSTRUMENT PANEL(NEW C-3 TYPE)

Fuel injection pump & governor

Fig 28 — FUEL INJECTION PUMPFig 31 — TIMERFig 32 — TIMER(PREVIOUS)Fig 35 — GOVERNORFig 36 — GOVERNOR(NOT BOOST COMPEMSATORFig 37 — GOVERNOR(FOR B00ST COMPEMSATOR

Fuel injectors & nozzles

Fig 30 — FUEL INJECTION VALVE

Fuel lines, tank & filter

Fig 34 — FUEL LINE

Gaskets, kits & spare parts

Fig 53 — GASKET SET

Generator (genset)

Fig 42 — GENERATOR

Intake and Exhaust

Fig 10 — SUCTION MANIFOLDFig 13 — EXHAUST BENDFig 16 — TURBOCHARGERFig 17 — AIR COOLERFig 22 — LUB. OIL SUCTION PIPE

Lubricating

Fig 4 — LUB.OIL SUMPFig 21 — LUB.OIL COOLERFig 23 — LUB. OIL PIPE

Mounting

Fig 6 — ENGINE BRACKET

Other / general

Fig 20 — BARANCERFig 46 — CLUCH ASSY(YX-10)Fig 47 — CLUCH ASSY (YX-15)

Pistons, rods & liners

Fig 19 — PISTON & CONNECTING ROD

Tools & labels

Fig 5 — LABELSFig 45 — TOOLSFig 52 — SPECIAL TOOLFig 54 — SAFETY LABEL
📚 Manuals & Sources
Specs— none yet
Operator's Manual— none yet
Service / Workshop Manual— none yet
Parts Catalog / List— none yet
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Category
Marine
Engine family
4JH-HT
Year range (approx)
1985–1989
Cylinders
4
Rated output
66 hp (48.5 kW)
Bore × stroke
78 × 86 mm
Displacement
1644 cc
Max rpm
3600
Continuous rpm
3400
Aspiration
Turbocharged