2001 Yanmar 6LY2-STE, 6LY2A-STP, and 6LYA-STP Marine Diesel Engine Service Manual (P/N HINSHI-H8-011-1)

This Yanmar service manual covers the 2001 6LY2-STE, 6LY2A-STP, and 6LYA-STP vertical water-cooled, four-cycle marine diesels. Publication No. HINSHI-H8-011-1 identifies the first revised edition, June 2001, which added the two STP models.

Text search and diagram navigation: Text search is limited to the added cover; the technical pages have no searchable text layer. Embedded bookmarks lead to chapters and many subsections. Small labels in the B-, C-, and D-type wiring diagrams require zooming.

• Engine repair: Cylinder-head inspection and assembly, valve seat correction, piston and ring measurement, crankshaft and main bearing checks, and timing-gear inspection.

• Fuel injection equipment: Pump and governor overhaul, pre-stroke and injection-timing adjustment, nozzle opening-pressure adjustment, fuel feed pump testing, and automatic advancing timer service.

• Turbocharger system: RHC7W disassembly, rotor-play measurement, bearing inspection, reassembly checks, and troubleshooting for smoke, oil loss, low output, and vibration.

• Lubrication and cooling: Oil-pump inspection, oil-pressure control, cooler leak tests, seawater-pump service, freshwater-pump inspection, and thermostat testing.

• Reduction and reversing gear: KMH6A/KMH6A1 clutch and valve-body service, shaft shimming, hydraulic-system references, and optional remote control installation.

• Electrical diagnosis: Starter motor and alternator overhaul and tests, instrument-panel wiring, warning-device checks, and tachometer fault diagnosis.

Written for service and maintenance engineers, this manual assumes prior engine knowledge and omits material considered common knowledge.

Engine Repair and Model-Specific Service Data

This factory reference provides specifications for the camshaft and tappets, connecting rod assembly, flywheel dimensions, and crankshaft bearing clearances. Exploded assembly views, torque tables, head-bolt tightening sequences, valve-clearance specifications, and wear limits support the inspection and assembly work.

The 6LYA-STP has its own dry-sleeve selection data and piston specifications. Model-specific piston identification marks, nozzle data, and injection-timing references help match parts and settings to the engine before repair.

Performance curves and dimensional drawings cover the engine configurations and marine-gear installations. Engine removal, disassembly, reassembly, and test-running checks are covered, though the overall teardown chapter summarizes key points rather than detailing every operation.

Injection Pump Calibration and Turbocharger Service

Pump work goes beyond timing adjustment: the YPES-6AL2 sections cover plunger and delivery-valve pressure tests, cylinder-to-cylinder delivery balancing, boost-compensator adjustment, and separate calibration tables for the engine variants. Pump readjustment after major component replacement requires a dedicated pump tester.

Turbocharger references include the RHC7W sectional view, shaft and bearing wear limits, and intake/exhaust fault tables. The assembly notes warn that incorrect turbine-shaft insertion can damage the floating bearings.

Cooling Circuits and Oil-System Checks

The piping diagram separates freshwater, seawater, fuel, and lubricating-oil routes, including turbocharger cooling. Cooling coverage includes heat-exchanger and pressure-cap tests, the expansion tank, and cap tester 126650-92750.

Seawater-pump impeller and seal service is covered, while the freshwater pump is treated as a replacement assembly. The lubrication sections also address the oil pressure control valve, full-flow and bypass filters, piston cooling nozzles, and optional rotary waste oil pump.

KMH6A/KMH6A1 Marine Gear and Controls

The gear section includes a hydraulic-system diagram and sectional view, wet-clutch inspection, input/output gear work, and bearing-clearance adjustment. It distinguishes the KMH6A used with the 6LYA-STP from the KMH6A1 used with the 6LY2-STE and 6LY2A-STP.

MG5061A, MG5050A, and HSW800A2 appear in the specifications, but internal service work on those gearboxes requires the respective manufacturer's manual.

The hydraulic-pump notes warn that overtightening its mounting bolts can seize the pump. The optional Morse MT-3/MV remote-control sections cover cable installation and ahead-neutral-astern adjustment.

Panel Wiring and Symptom-Based Troubleshooting

The three main wiring diagrams distinguish New B-, C-, and D-type control panels, including optional second-station connections where shown. Coupler views, wire-color codes, and the alternator circuit diagram support electrical fault tracing.

The repair sections cover the S13-68A starter, LR180-03B alternator, warning switches, gauge senders, and tachometer sensor. Charging-system flowcharts and engine cause-and-effect charts help separate electrical, fuel-supply, turbocharger, and marine-gear faults before components are removed.

Any actual maintenance should be performed by qualified marine technicians following the manual's precautions for engine lifting, rotating parts, and battery isolation.

Printable PDF and Included Revision Pages

Supplied as one printable, English-language, 234-page PDF. That total includes one additional front cover and the 14 pages added with the first revision: six safety pages, seven technical inserts, and the revision-history page.