Yanmar 1GM10, 2GM20, 3GM30, SHM35 Diesel Engine Service Manual (P/N 0000A0A1361-9107)

This 463-page PDF carries Yanmar publication code 0000A0A1361 and covers 1GM10/1GM10C, 2GM20/2GM20F/2GM20C, 3GM30/3GM30F/3GM30C, and 3HM35/3HM35F/3HM35C marine diesels. The manual identifies F as fresh-water cooling and C as a sail-drive engine configuration; an unmarked model uses direct sea-water cooling. Compiled by Yanmar for engineers engaged in sales, service, inspection, and maintenance, it is best suited to trained marine-diesel technicians and experienced rebuilders because material treated as common knowledge is omitted.

• Internal-engine repair: Separate teardown and reassembly chapters cover direct sea-water and fresh-water engines. Work includes cylinder-block crack and bore inspection, reboring and oversize-piston data, cylinder-head and valve service, piston/connecting-rod/crankshaft inspection, main bearings, camshaft, timing gears, flywheel, and test running after assembly.

• Fuel-system repair: Covers the injection pump, matched plunger/barrel components, control rack, injection timing, pump-tester adjustment, nozzle spray and seat tests, nozzle-pressure setting, feed pump, filter, and the governor, injection limiter, no-load maximum-speed limiter, idle adjuster, and engine-stop controls.

• Cooling-system work: Separates direct sea-water and heat-exchanger systems, including rubber-impeller pumps, thermostats, anticorrosion zincs, fresh-water pump, heat exchanger, filler cap/subtank, and cooling-temperature switches. It also documents factory conversion of a 2GM20, 3GM30, or 3HM35 to the corresponding F configuration, followed by operational and leak checks.

• Lubrication, intake, and exhaust: Traces the drilled oil galleries and services the trochoid pump, filter bypass, pressure regulator, and primary/secondary oil-pressure measurement. Intake-silencer, crankcase-breather, water-cooled exhaust-manifold, mixing-elbow, and carbon/deposit inspection data are also included.

• Marine-gear repair: Divides coverage among KM2-C/KM3-A cone clutches, the 3HM35F's KBW10-E multi-disc unit, later KM2P/KM3P gears, and the KM3V V-drive. Procedures cover shifting devices, clutch/speed/stop remote controls, inspection, teardown/reassembly, bearing and shaft setup, shim selection, and backlash adjustment.

• Electrical diagnosis: Includes the battery, starter motor, standard and optional alternators, A- and B-type instrument panels, warning devices, and tachometer, with wiring diagrams, component tests, charging diagnosis, fault charts, and reassembly checks.

• Factory data and tools: Provides model-specific torque tables, fits and clearances, wear limits, capacities, lubrication and oil-pressure checks, fuel-injection test data, electrical test values, packing/adhesive locations, and a dedicated special-tool section.

Serial and Configuration Checkpoints

Later marine gears have explicit serial breaks: KM2P for the 1GM10 at E/# 03413 and later, KM2P for the 2GM20(F) at E/# 03567 and later, and KM3P for the 3GM30(F) at E/# 01888 and later, all effective from August 1985. The C-model specification table lists SD20 and SD30 sail drives, but there is no dedicated sail-drive disassembly or overhaul chapter. Detailed transmission repair in this PDF concerns the listed KM/KBW marine gears and the KM3V V-drive.

Drawings, Troubleshooting, and Service Equipment

Among the most useful illustrations are model-specific engine cross-sections, the valve-timing diagram, direct sea-water and fresh-water cooling and piping diagrams, KM-series and KM3V sectional and power-transmission views, A/B instrument-panel wiring diagrams, and alternator and instrument-panel troubleshooting charts. The operating chapter adds cause-and-corrective-action tables for starting trouble, sudden shutdown, output loss, abnormal exhaust, overheating, oil-pressure problems, and engine knock.

Named service tools include main-bearing replacers 124085-92400 and 128670-92400, piston-pin tools 124085-92260 and 128670-92260, valve insertion/extraction tool 124085-92250, fuel-injection-valve replacer 101104-92180, and the 3HM35F output-shaft nut wrench and coupling lock 177099-09010/177099-09020. The manual also identifies measuring equipment for bore, clearance, torque, and injection work.

Repair Cautions and Scope

The injection-pump chapter warns that cylinder-specific parts must remain grouped; mixing them makes reassembly impossible without a pump tester. Excessive delivery-valve-holder torque can distort the plunger, bind the control rack, and damage the pump body or valve gasket. The cooling section likewise warns that dry-running the sea-water pump or turning the engine in reverse damages the rubber impeller.

This is not a beginner's repair tutorial. Follow the factory precautions for hot pressurized coolant, batteries, lifting, and test running before dismantling or servicing the engine.