Every system on the Yanmar ViO27-6 compact excavator gets its own chapter in this 565-page factory service manual, from engine internals and fuel injection through hydraulic circuit operation and undercarriage rebuild procedures. Inside, you get full hydraulic schematics for every attachment circuit: boom, arm, bucket, swing, blade, and travel, including non-deviation travel during combined operations. Wiring diagrams cover the engine start/stop system, battery charge circuit, auto deceleration controls, and the LCD monitor alarm system. Swing bearing M12 bolts torque to 117.7 to 127.5 N·m (Loctite 262 required), and travel motor sprocket M10 mounting bolts call for 44.1 to 58.9 N·m. Your machine is down. Open the PDF on any device, use the bookmarks to jump straight to hydraulics or the error code list, and get back to digging.
What's Inside This Yanmar ViO27-6 Manual
| System | Pages | Key Topics |
|---|---|---|
| General Cautions for Maintenance Work | 12-19 | Correct Work, Safety Precautions, Preparations, Cautions for Disassembly and Reassembly, Cautions for Removal and Installation of Hydraulic Equipment, Cautions for Removal and Installation of Hydraulic Piping, Cautions for Handling Seals, Correct Installation of Hydraulic Hose, Specifications of Hydraulic Hose, Air Release of Hydraulic Equipment |
| Technical Data | 24-42 | Specifications, Outline Drawing and Working Area, Weight List of Main Parts, Lifting Capacity List, Specifications for Attachment, Periodic Inspection and Servicing, Fuel, Lube Oil and Grease Recommended, Hydraulic Circuit Schematic, Wiring Diagram |
| Service Standards | 51-79 | Machine Performance, Engine, Undercarriage (Rubber Track Specifications, Steel Track Specifications, Common Specifications of Steel & Rubber Crawlers), Controls, Hydraulic Equipment, Implement, List of Tightening Torque, Pressure Adjustment |
| Engine | 83-226 | 4-1 Safety, 4-2 Engine, 4-3 Fuel System, 4-4 Cooling System, 4-5 Lubrication System, 4-6 Starter Motor, 4-7 Alternator, 4-8 Electric Wiring |
| Electric System | 227-254 | Electric Equipment of Machine (Parts Layout of Electrical Equipment, LCD Monitor and Alarm Systems), Circuit Description of Engine Start and Stop (Battery Charge) |
| Hydraulic System | 255-454 | Outline (Control Valve Operation, Additional Operation of Control Valve) |
| Adjustment and Repair | 455-552 | Engine and Electric Equipment (Removal Reinstallation: Starter Motor, Radiator and Oil Cooler, Fan Belt) |
| Troubleshooting | 553-565 | Non-Breakdowns (Natural Release of Bucket, Discontinuous Arm Movement, Drifting of Upperstructure on Quick Travel Operation, Thermal Shock of Travel Motor, Elongation of Boom Swing Cylinder on 65 Degrees Swing, Telescopic Motion of Boom Swing Cylinder with Lock Lever Set to Lock Position, Time Lag on Travel Speed Switching, Fluctuation in Oil Level of Hydraulic Oil Tank Due to Temperature Change) |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Travel motor and sprocket mounting bolt (M10) tightening torque | 44.1 to 58.9 N·m | p. 70 |
| Swing bearing × Track frame tightening torque | 117.7 to 127.5 N·m | p. 69 |
| Swing bearing × Turning frame tightening torque | 117.7 to 127.5 N·m | p. 69 |
| Suction filter filtration accuracy | 150 u | p. 28 |
| Return filter filtration accuracy | 10 u | p. 28 |
| LO filter filtration area | 800 cm2 | p. 31 |
| LO filter valve opening pressure | 0.08 to 0.12 MPa | p. 31 |
| Fuel filter filtration area | 432 sq.cm | p. 31 |
| Hydraulic oil tank capacity | 25 L | p. 28 |
| Hydraulic oil type | ISO VG46 | p. 40 |
| Radiator cap pressure | 88.3 kPa | p. 31 |
| Cooling fluid type | YANMAR POWER COOLANT B–36 | p. 40 |
Yanmar ViO27-6 Common Problems This Manual Covers
Yanmar ViO27-6 hydraulic functions slow or intermittent after warm-up, bucket won't lift
Check hydraulic oil level first — tank capacity is 25 L (ISO VG46). If level is correct, inspect the return filter; bypass valve opens at 0.147 MPa, which means a clogged 10-micron return filter is forcing bypassed dirty oil back into the circuit. Drain and refill the tank, replace both the suction (150 micron) and return filter elements, then verify system relief pressure reaches 20.6 MPa at the work port. See the pump troubleshooting table starting.
Manual Section: Hydraulic Pump TroubleshootingEngine starts but loses power, runs rough, or stalls under load
Drain the water separator bowl immediately — it uses a mesh filter type and water in diesel kills power fast. Replace the fuel filter (filtration area 432 sq.cm) if it's at or past its service interval on the maintenance schedule at page 38. Check fuel injection valve opening pressure: it should measure 12.3 to 13.3 MPa for ID Mark A injectors on page 59. If pressure is low, the injector is worn and needs replacement before the engine will pull full load cleanly.
Manual Section: EngineCoolant temperature warning, overheating, or unexplained coolant loss
Check the radiator cap seal first — rated at 88.3 kPa, a weak cap lets coolant boil out under load. Top up with YANMAR POWER COOLANT B-36 to the correct fill: 3.4 L in the radiator and 0.4 L in the expansion flask. Inspect all hoses and fittings for cracks or wet spots, then confirm the fan belt tension and condition per the adjustment procedures at page 455. If coolant loss continues with no visible external leak, pressure-test the block for a head gasket issue.
Manual Section: EngineTrack travel pulls to one side or one track moves slower than the other
Measure track sag at mid-span between the drive sprocket and front idler — correct tension for rubber tracks is 8 to 13 mm of deflection. Adjust grease in the tension cylinder until sag falls within that range. If tension is correct, check the travel motor mounting bolts at page 70: M10 bolts torque to 44.1 to 58.9 N·m with ThreeBond 1324. Persistent one-sided deviation with correct tension points to a hydraulic issue in the travel circuit — work through the travel motor troubleshooting table.
Manual Section: Travel Motor TroubleshootingAttachments or implements drift down on their own with controls released
Verify this isn't a known non-breakdown first — natural bucket release and arm discontinuity under specific conditions are documented as normal phenomena starting at page 553. If drift exceeds normal ranges, go to the control valve troubleshooting section starting, which covers cylinder drift and implement lowering on start-up. Inspect the pilot valve secondary pressure: unstable pilot output traced to the pilot valve troubleshooting procedure can cause erratic or drifting attachment behavior even when the main control valve checks out clean.
Manual Section: Control Valve TroubleshootingHydraulic hose or fitting leaks fluid after repair or service work p. 12
Torque fittings to spec using the tables at page 74: parallel pipe thread 3/8 takes 44.1 to 53.9 N·m, taper pipe thread 3/8 takes 29.4 to 39.2 N·m. For suction hose clamps (Hose clip 60), torque is 4.5 to 5.9 N·m; for hydraulic hose clamps (Hose clip 13), torque is 2.5 to 3.4 N·m. Under-torqued fittings on a 25 L ISO VG46 system at 20.6 MPa relief pressure will seep immediately under load. After tightening, cycle the machine through full working range at operating temperature and reinspect all joints.
Manual Section: General Cautions for Maintenance WorkFrequently Asked Questions
How do I reset error codes on a Yanmar ViO27-6?
To clear error codes on the Yanmar ViO27-6, you generally need to resolve the underlying cause of the error. After fixing the issue, turn the starter switch to the “OFF” position and then back to the “ON” position to check if the error code is displayed again. This procedure is applicable for various ECU malfunctions and auto deceleration alarm lamp errors.
How do I clear a hydraulic warning on a Yanmar ViO27-6?
To clear a hydraulic warning, first identify and resolve the specific issue, such as an abnormal hydraulic oil temperature or a sensor malfunction. For example, if a hydraulic oil temperature sensor error occurs, check the connectors and harnesses. After addressing the cause, turn the starter switch to the “OFF” position and then to the “ON” position to clear the error code.
What does alarm code mean on a Yanmar ViO27-6?
The service manual provides a comprehensive 'Error Code List' that details the meaning of various alarm codes. Each entry includes the error code, its classification, a description of the error, detection conditions, potential causes, and corrective measures. For example, error code '00 000091.00' indicates a 'Caution Accelerator sensor malfunction: above normal operating range (SAEJ1843)'.
How to reset Yanmar ViO27-6 fault code
To reset a fault code on the Yanmar ViO27-6, you must first address the root cause of the fault. Once the issue is resolved, cycle the starter switch by turning it to the “OFF” position and then back to the “ON” position to verify if the fault code has cleared. This method is specified for various ECU malfunctions and other system errors.
What do I get after purchasing this Yanmar ViO27-6 manual?
Immediate download of the complete 565-page searchable Service Manual. Access it on any device, from a laptop at your desk to a phone in the field.
Is this Yanmar ViO27-6 Service Manual printable?
No restrictions at all. Print individual pages, full chapters, or the entire manual. The PDF is completely unlocked.
Does this Service Manual have electrical diagrams?
Yes, this Yanmar ViO27-6 Service Manual includes complete electrical wiring diagrams, wire routing, and connector pinouts.
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