This 328-page Yanmar SV20 service manual is built to get your compact excavator back to factory condition. It carries the full hydraulic circuit schematics for the pilot valve and swing motor, complete engine teardown procedures, and step-by-step troubleshooting charts. The electrical section lays out the wiring from the starter motor through the monitor and alarm systems. You can confirm the rubber crawler against its 10 mm wear limit, check that the idler shaft diameter hasn't dropped below 279 mm, and set the LS pressure relief valve to 20 N.m, all with the factory numbers in front of you. When the machine is down, every hour in the shop costs money. The file is cleanly bookmarked, so pull it up on a tablet, take it out to the dirt, and work straight from the page.
What's Inside This Yanmar SV20 Manual
| System | Pages | Key Topics |
|---|---|---|
| General Cautions for Maintenance Work | 11-24 | Correct Work, Safety Precautions, Preparations, Cautions for Disassembly and Reassembly, Cautions for Removal and Installation of Hydraulic Equipment |
| Technical Data | 25-36 | 2-1 Specifications, 2-2 Outline Drawing and Working Area, 2-3 Weight List of Main Parts, 2-4 Lifting Capacity List |
| Service Standards | 37-56 | Machine Performance, Engine, Undercarriage (Rubber Crawler Specifications, Common Specifications of Steel & Rubber Crawlers), Controls, Hydraulic Equipment (Hydraulic Cylinders) |
| Engine | 57-100 | General (Engine External Views), Measurement |
| Hydraulic System | 101-104 | 5-1 Outline, 5-2 Hydraulic Circuit Schematic |
| Hydraulic Equipment | 105-198 | 6-1 Hydraulic Pump, 6-2 Control Valve, 6-3 Pilot Valve, 6-4 Swing Motor, 6-5 Travel Motor |
| Adjustment and Repair | 199-276 | Electric Equipment of Machine (Parts Layout of Electrical Equipment, Monitor and Alarm Systems, Wiring Diagram, Circuit Description of Engine Start and Stop, And Battery Charging, Removal and Reinstallation of Engine, Removal and Reinstallation of Starter Motor, Removal and Reinstallation of Fuel Injection Pump, Removal and Reinstallation of Fuel Tank, Removal and Reinstallation of Radiator) |
| Periodic Inspection and Servicing | 277-280 | 8-1 List of Periodic Inspection and Servicing |
| Fuel, Lube Oil and Grease Recommended | 281-284 | Engine Oil, Travel Reduction Gear, Hydraulic Oil, Fuel, Engine Cooling Water, Grease |
| Troubleshooting | 285-324 | 10-1 Non-Breakdowns, 10-2 Troubleshooting |
| Reference Data | 325-328 | 11-1 Specifications for Attachment |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| LS pressure relief valve adjustment torque | 20 ± 10% N.m | p. 123 |
| Travel motor valve body assembly to base plate bolts (Hexagon socket head bolt 79) | 14.4 to 15.9 N·m | p. 189 |
| Hydraulic pump cover bolts (SCREW TCEI M 10X50 UNI 5931-12.9) | 70 Nm | p. 113 |
| Rubber crawler wear limit (A) | 10 mm | p. 47 |
| Idler & shaft D (diameter) wear limit | Ø279 | p. 45 |
| Hose type (SAE J517, 100R1) 02 working pressure | 17.2 MPa | p. 17 |
| Hose clip 13 tightening torque | 2.5 to 3.4 N·m | p. 52 |
| Floating seal 2 replacement condition | No excessive flaws, wear or seizure | p. 192 |
| Oil seal 30 replacement condition | No flaws, distortion or excessive wear. Not hardened | p. 191 |
| Fuel filter element replacement interval | Every 200 hrs | p. 278 |
| Engine oil filter element replacement interval | Every 250 hrs | p. 277 |
| Air cleaner element replacement interval | Every 250 hrs | p. 277 |
Yanmar SV20 Common Problems This Manual Covers
Yanmar SV20 excavator right track is weak and machine will not travel straight. p. 45
Measure track tension. Check the rubber crawler wear limit on page 45; replace if it exceeds 10 mm. Inspect track rollers and tighten the track roller nut to 78.4 to 98.0 N·m as shown on page 52. Clear any packed mud from the undercarriage.
Manual Section: Travel System Operation IssuesBoom cylinder drifts down under load and bucket has weak digging force. p. 26
Inspect system pressures and check for leaks. Verify the system relief set pressure P1 is at 21 MPa using the specs on page 26. Check the hydraulic oil tank capacity on page 28 and fill to 32 L if low. Tighten any loose fittings immediately.
Manual Section: Work Implement Hydraulic System IssuesEngine turns over slowly in cold weather, runs inconsistently, and will not start. p. 278
Drain the water separator and inspect the fuel system. Replace the fuel filter element every 200 hrs according to the schedule on page 278. Test the battery voltage to ensure it meets the 12-45 V-Ah 5 hrs rate capacity shown on page 30.
Manual Section: Engine Starting and Charging IssuesCoolant temperature gauge reads high and engine emits black smoke under load. p. 277
Clean debris from the radiator grilles and check the air filter. Replace the air cleaner element every 250 hrs as detailed on page 277. Inspect all coolant lines and tighten radiator hose clamps to 3.92 to 4.91 N·m using the torque specs on page 51.
Manual Section: Engine Performance IssuesFrequently Asked Questions
How do I reset the hydraulic pressure or PTO relief setting on a YANMAR SV20?
To set the maximum hydraulic pressure, put a 6 mm socket wrench on the LS pressure relief valve and tighten the counternut to 20 ± 10% N.m. It is part of the starting and maximum pressure setup for the control block, which keeps the system inside its specified limits.
How do I perform maintenance checks on a YANMAR SV20?
The SV20 has set service intervals: daily, then every 50, 100, 250, 500, and 1000 hours. They cover general machine condition, lube oil, the hydraulic system, grease points, the undercarriage, steering equipment, and electrical equipment. For the daily checks, look for parts that have come loose or broken and retighten any loosened bolts and nuts.
What are the replacement specifications for Track tension/undercarriage components?
The manual provides service standards for undercarriage components, including rubber crawler specifications like shoe width (250 mm), lug height (23 mm), and core metal pitch (48.5 mm). For track tension adjustment, a grease adjuster is used. The wear limit for rubber crawler lug height is 10 mm.
What are the replacement specifications for Hydraulic hoses?
Hydraulic hoses for the YANMAR SV20 are specified by type, hose diameter, inner/outer diameter, and working pressure. For example, a SAE J517, 100R1 type hose with a 02 hose dia. has an inner dia. of 6.3 mm, an outer dia. of 13.5 mm, and a working pressure of 17.2 MPa. The manual also details correct installation procedures to prevent twisting and ensure proper slackness.
How quickly can I access this manual after buying?
Immediate download of the complete 328-page searchable Service Manual. Access it on any device, from a laptop at your desk to a phone in the field.
Can I print this manual?
Yes. The PDF has no DRM restrictions, so print any page or section you need for your shop. Works with any standard printer.
Are hydraulic system diagrams in this Yanmar SV20 Service Manual?
Yes, complete hydraulic schematics with flow diagrams, valve configurations, and pressure specifications are included.
Document Quality
This document is a scanned PDF with an OCR layer, allowing you to search and copy the full text. The main text is crisp and easy to read throughout. Diagrams and illustrations are raster images, meaning some labels may lose sharpness when zoomed in, but are generally legible. Pages are mostly clean, though some exhibit minor scan artifacts like slight skewing. There are several blank pages interspersed, likely serving as intentional dividers or blank backsides.
Reviews
There are no reviews yet.