Three machines, one book: the GR2020G, GR2120, and GR2120AU share this Operator Manual (OEM #K1260-7121-4), 105 pages built around safe, productive mowing. Eleven pages handle safety alone, from slope operation to PTO use and load limits, and the instrument panel section walks through the Easy Checker, hydraulic lift lever, cruise control knob, and KRA override switch. Service intervals run from daily tire and fluid checks out to 4-year hose replacements, with capacities listed for engine oil, transmission fluid, and front axle case oil. Front turf tires take 160 kPa (24 psi), rears 150 kPa (22 psi), and blade bolts torque to 103-118 N-m (76-87 lbf-ft) on every swap. Bookmarked throughout, so you search a keyword, land on the section, and get the mower running again.
What's Inside This Kubota GR2020G, GR2120, GR2120AU Operator Manual
| System | Pages | Key Topics |
|---|---|---|
| Safe Operation | 8-19 | Before Operating |
| Servicing of Lawn and Garden Tractor | 20 | Machine serial number, Engine serial number, Mower serial number, Warranty, Scrapping |
| Specifications | 21-22 | Model Gr2020G Gr2120 Gr2120Au, Engine, Capacity, Machine, Dimensions, Mower, Model Rck48Gr Rck54Gr, Grass Catcher |
| Implement Limitations | 23-24 | Maximum Axle Loading Weight, Wf Wr, Ballast |
| Instrument Panel and Controls | 25 | Easy Checker, Choke Lever, Throttle Lever, Head Light Switch, Parking Brake Pedal, PTO Lever, Hydraulic Lift Lever, Hour Meter |
| Mower Mounting | 26-29 | Attaching The Mower (Mounting The Mower Deck), Parallel Linkage, Mower Deck, Mower Lift Stoppers, Dismounting The Mower Deck |
| Operating the Engine | 30-35 | Starting The Engine (Key Switch, Throttle Lever And Choke Lever, Choke Lever, Cold Weather Starting, Block Heater), Stopping The Engine (Engine Stop Lever, Engine Stop) |
| Operating the Machine | 36-41 | Operating New Machine (Changing Lubricating Oil For New Machines, Engine Break-In, Machine Break-In) |
| Operating the Mower | 44-48 | KRA System Normal Operating Mode, PTO Lever, KRA System Override Mode |
| Cleaning | 49 | Cleaning with Water |
| Tire and Wheels | 50-51 | Tires, Wheels |
| Maintenance | 52-61 | Service Intervals (Air Cleaner Precleaner Element Clean, Air Cleaner Air Cleaner Element Clean, Air Cleaner Air Cleaner Element Replace, Engine Oil Change, Engine Oil Filter Replace, Transmission Fluid Change, Transmission Oil Filter Replace, Transmission Strainer Clean, Front Axle Case Oil Change, Front Axle Pivot Adjust, Engine Shroud Panel Clean, Engine Shroud Clean, Engine Start System Check, OPC System Check, PTO Control System Check, Oiling, Greasing, Mower Gear Box Oil Check, Mower Gear Box Oil Change, Carbon Canister Air Filter Check, Battery Condition Check, Brake Check, Fuel Filter Element Check, Fuel Filter Element Replace, Spark Plug Condition And Gap Check, Fuel Line Check, Fuel Line Replace, Hydraulic Hose Check, Hydraulic Hose Replace, Mower Gear Box Oil Seal Check, Mower Gear Box Oil Seal Replace, Fuel System Bleed, Fuse Replace, Blade Replace, Mower Belt Replace, Air Cleaner Element Clean, Air Cleaner Element Replace, Fan Drive Belt Check, Fuel Injection Nozzle Injection Pressure Check, Injection Pump Check, Radiator Clean, Coolant Change, Radiator Hose And Clamp Check, Radiator Hose And Clamp Replace, Intake Air Line Check, Intake Air Line Replace, Engine Breather Hose Check, Engine Breather Hose Replace) |
| Periodic Service | 62-98 | How To Open The Hood |
| Adjustment | 99-100 | General Torque Specification, Tightening Torque Chart |
| Troubleshooting | 102-104 | Engine Troubleshooting, Battery Troubleshooting, Machine Troubleshooting, Mower Troubleshooting, Air Cleaner Element, Air Cleaner Paper Element, Amount Of Fuel And Refueling |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| All Models | ||
| Blade bolt tightening torque | 103 to 118 N-m (76 to 87 lbf-ft, 10.5 to 12.0 kgf-m) | p. 77 |
| Recommended inflation pressure (Turf tire, Front) | 160 kPa (1.6 kgf/cm², 24 psi) | p. 31 |
| Recommended inflation pressure (Turf tire, Rear) | 150 kPa (1.5 kgf/cm², 22 psi) | p. 31 |
| Hydrostatic transmission oil capacity | 3.3 L (3.5 U.S.qts.) | p. 21 |
| Front tire pressure (Turf) | 160 kPa (24 psi) | p. 31 |
| Rear tire pressure (Turf) | 150 kPa (22 psi) | p. 31 |
| GR2120, GR2120AU | ||
| Fan drive belt deflection | approx. 10 mm (0.39 in.) with 98 N (10 kgf) finger pressure | p. 63 |
| Compressed air pressure for cleaning air cleaner element | under 205kPa (2.1kgf/cm², 30psi) | p. 53 |
| Engine oil capacity | 2.8 L (3.0 U.S.qts.) | p. 21 |
| Fuel tank capacity | 18 L (4.8 U.S.gals.) | p. 21 |
| GR2020G | ||
| Engine oil capacity | 1.9 L (2.0 U.S.qts.) | p. 21 |
| Fuel tank capacity | 16 L (4.2 U.S.gals.) | p. 21 |
Kubota GR2020G, GR2120, GR2120AU Common Problems This Manual Covers
Kubota GR2120 engine stalls or loses power when mowing uphill on steep slopes p. 8
Review the slope safety rules on page 8 before taking the machine onto any incline. Mow straight up and down slopes, never across, to avoid a tip-over, and hold engine speed at full throttle. Front tires should sit at 160 kPa (24 psi) and rears at 150 kPa (22 psi) per page 31 for traction and stability.
Manual Section: Safe OperationMachine will not move or hydrostatic drive fails to respond when pedal is depressed p. 103
Consult the machine troubleshooting chart on page 103 for drive system faults. Make sure the parking brake is fully released and the transmission oil level is correct; total capacity is 3.3 L (3.5 U.S. qts.) per page 21. Confirm no selector lever or linkage sits in the wrong position before re-testing the foot pedal.
Manual Section: Machine TroubleshootingEasy Checker warning indicator stays on or flashes during normal mowing operation p. 25
Identify the active indicator using the Easy Checker panel key on page 25. If the engine temperature light is on, stop immediately and inspect the engine shroud and radiator screen for packed grass blocking airflow. Clean the screen before restarting. On GR2120 and GR2120AU, replace coolant every 2000 hours or 2 years per page 54.
Manual Section: Instrument Panel and ControlsEngine cranks slowly or fails to start reliably during cold morning startup p. 30
Follow the cold weather starting procedure on page 30. Set the choke lever to fully closed and hold the throttle at the slow position before cranking. Inspect battery terminals for corrosion using the battery troubleshooting table on page 102. On GR2020G, also check spark plug gap, which should measure 0.76 mm (0.030 in.) per page 87.
Manual Section: Operating the EngineUneven cut or persistent streaks of uncut grass left behind the mower deck p. 104
Match the streaking or uneven cut against the mower troubleshooting table on page 104. Inspect blade sharpness and replace any worn or bent blades. After removing a blade, torque the bolts to 103 to 118 N-m (76 to 87 lbf-ft) per page 77. Confirm the deck is level and the parallel linkage is seated correctly.
Manual Section: Mower TroubleshootingDischarge chute clogs repeatedly when cutting wet or tall grass during mowing season p. 104
Trace plugged-chute causes in the mower troubleshooting table on page 104. Slow your ground speed in thick or wet grass, and bring the engine to full throttle before engaging the PTO. Dull blades pack the chute, so check sharpness. After resharpening, torque blade bolts to 103 to 118 N-m (76 to 87 lbf-ft) per page 77.
Manual Section: Mower TroubleshootingFrequently Asked Questions
What is the torque spec for Kubota GR2120 wheel nuts?
When re-fitting a wheel, tighten the front wheel bolts to 108.5 to 130.2 N-m (80 to 96 lbf-ft) and the rear wheel nuts to 77.6 to 90.2 N-m (57.2 to 66.5 lbf-ft). Recheck after travelling 200 m (220 yards) and changing directions several times.
What is the torque spec for Kubota GR2020/GR2120 mower deck spindle bolts?
When attaching the blades, tighten the blade bolts from 103 to 118 N-m (76 to 87 lbf-ft, 10.5 to 12.0 kgf-m) of torque. To prolong the service life of the blades, rearrange them periodically as shown in the figure.
How to reset Kubota GR2120 PTO switch
The manual does not describe a "reset" procedure for the PTO switch itself. However, to enable engine starting or to disengage the KRA system override mode, the PTO lever must be in the "DISENGAGED" position. For example, when starting the engine, ensure the PTO lever is disengaged (page 30). If the KRA system override mode is active, it will remain so until the PTO lever is returned to the "DISENGAGED" position (page 48).
How to reset Kubota GR2020 safety interlock
The manual does not provide a generic "reset" procedure for safety interlocks. Instead, to clear a safety interlock condition and allow the engine to start or operate, the specific unsafe condition must be corrected. For instance, to start the engine, the parking brake must be applied and the PTO lever must be in the "DISENGAGED" position (page 30). If the Operator Presence Control (OPC) system triggers a shutdown, the operator must be seated (page 52).
How will I receive this Kubota GR2020G, GR2120, GR2120AU Operator Manual?
It is a 105-page searchable PDF ready for immediate download. Works on any device, so you can pull it up on your phone right at the machine. No shipping, no waiting.
Are there any print restrictions on this Kubota GR2020G, GR2120, GR2120AU?
Yes. The PDF carries no DRM restrictions, so you can print any page or section you need for your shop. It works with any standard printer.
Document Quality
This document is a scanned PDF, not a native digital file. An OCR layer is included, allowing you to search and copy the full text content. The text is generally clear and readable throughout, without significant blurriness or fading. All diagrams and illustrations are raster images, but they are clear and their labels are easy to read. The pages are clean, free of scan artifacts, stains, or skewed content, and there are no notable blank or filler pages.
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