All 153 pages of this Kubota Z122R-AU and Z122RKW-AU Workshop Manual (OEM #9Y111-13423) zero in on one machine: your Kubota utility vehicle, from engine to mower deck. Inside, you get exploded-view diagrams across the transaxle, front axle, and lift system, full wiring diagrams covering the start system, OPC safety switches, PTO clutch, and charging circuit, plus hydraulic circuit schematics for the transaxle. Packed with 7 troubleshooting charts and 50 step-by-step service procedures, this manual walks you through every disassembly, inspection, and reassembly sequence the factory intended. Fill the transaxle case to exactly 1.66 L and torque your M10 fasteners to 36-44 N·m — no guessing, no forum math. Every hour your machine sits idle costs money. Bookmarked by system and keyword-searchable, pull up the exact procedure on your tablet and get back to work.
What's Inside This Kubota Z122R-AU, Z122RKW-AU Manual
| System | Pages | Key Topics |
|---|---|---|
| Record of Revisions | 3 | battery label, PTO switch, main switch, PTO switch connector illustration, transaxle oil specification, HST tension spring reassembly procedure |
| Information | 4-16 | Safety First, Safety Decals, Specifications, Dimensions |
| General | 17-50 | Identification (Serial Number), Handling Precautions For Electrical Parts And Wiring, Battery, Fuse, Connector, Handling of Circuit Tester, Color of Wiring, Lubricants And Fuel |
| Engine | 51-67 | Structure, Fuel System, Lubrication System, Troubleshooting, Servicing Specifications, Tightening Torques, Checking, Disassembling and Servicing |
| Transaxle | 68-91 | Structure, External Components, Inner Components, Troubleshooting, Servicing Specifications, Tightening Torques, Checking, Disassembling and Servicing |
| Front Axle | 92-98 | Structure, Troubleshooting, Tightening Torques, Checking |
| Lift System | 99-105 | Structure, Troubleshooting, Tightening Torques, Checking |
| Electrical System | 106-135 | Wiring Diagram, Start System and OPC, Safety Switches, Relay, Charging System, Hour Meter, Head Light and PTO Clutch, Troubleshooting |
| Mower | 136-153 | Power Transmission, Troubleshooting, Servicing Specifications, Tightening Torques, Checking |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Fuel tank capacity | 12.2 L (3.22 U.S. gals, 2.68 Imp.gals) | p. 26 |
| Engine crankcase oil capacity | 2.1 L (2.2 U.S.qts, 1.8 Imp.qts) | p. 26 |
| Max engine power | 15.0 kW (21.5 HP) | p. 14 |
| Fuel tank capacity | 12.2 L (3.23 U.S. gals, 2.68 Imp. gals) | p. 14 |
| Engine crankcase capacity | 2.1 L (2.2 U.S. qts, 1.8 Imp. qts) | p. 14 |
| Transaxle oil capacity | 1.66 L (1.75 U.S. qts, 1.46 Imp. qts) | p. 14 |
| Front tire pressure | 170 kPa (24.7 psi) | p. 34 |
| Rear tire pressure | 83 kPa (12.0 psi) | p. 34 |
| Battery nominal voltage | 12V | p. 42 |
| Battery cold cranking amps | 300 A | p. 42 |
| Engine oil change interval | every 50 hours | p. 30 |
| Spark plug check interval | every 100 hours | p. 30 |
Kubota Z122R-AU, Z122RKW-AU Common Problems This Manual Covers
Kubota Z122R-AU engine cranks but won't start or starts hard in cold weather p. 58
Check the fuel shutoff valve is open and tank isn't empty (capacity 12.2 L). Inspect spark plugs — the service schedule calls for checks every 100 hours. Pull the air cleaner and look for a clogged element; replacement is due every 200 hours. If the battery cranks slowly, test it against the 300 A cold cranking amp spec and verify terminals are clean and tight. Work through the full start-fault sequence on pages 58-59.
Manual Section: Engine TroubleshootingEngine loses power under load, runs rough, or produces black exhaust smoke p. 58
Inspect the air cleaner element first — a restricted element is the fastest path to black smoke and power drop. Check spark plugs for fouling or incorrect gap; service interval is every 100 hours. Verify the fuel filter isn't due for its annual replacement. If rough running continues, review valve clearance: adjustment is scheduled every 300 hours. Consult the diagnostic table on pages 58-59 to isolate fuel, ignition, or mechanical causes.
Manual Section: Engine TroubleshootingMachine pulls left or right, won't track straight, or drives in one direction only p. 74
Check transaxle oil level before anything else. Verify both rear tires are inflated equally at 83 kPa (12.0 psi) — uneven pressure alone will pull the machine off-line. Inspect the transaxle linkage for bent or disconnected rods. If the unit only drives one direction, suspect a hydrostatic control fault; the full fault tree is on page 74. Confirm transaxle oil is not contaminated or foamy, which indicates internal seal issues.
Manual Section: Transaxle TroubleshootingMower deck blades won't engage or disengage slowly when PTO switch is activated p. 123
Check PTO clutch clearance — adjustment is required every 100 hours. Inspect the PTO belt for wear, glazing, or slipping; the belt replacement interval is 300 hours. Verify the PTO switch and its connector are seated fully (see wiring notes on page 106). If the blade turns but speed is slow, the belt may be loose before it's fully worn. Work through the PTO clutch fault sequence on page 123 to separate electrical from mechanical causes.
Manual Section: Electrical System Troubleshooting (PTO Clutch)Uneven cut: grass streaking, scalping on high spots, or strips of uncut grass left behind p. 141
Set the machine on a flat surface and measure blade height: the spec is 76 mm (3.0 in.) at the flat surface. Check that all four deck hangers are at equal height and that no lift linkage is bent or worn. Inspect blades for dullness, nicks, or imbalance — a dull blade tears rather than cuts and leaves a ragged stripe. Torque blade bolts to 103 to 118 N·m after any blade removal. Review the full cut-quality fault list on pages 141-142.
Manual Section: Mower TroubleshootingMower deck won't lift or lower when operator raises the lift lever p. 103
Inspect the lift linkage for bent rods, worn cam, or a detached spring. Verify the cam flange nut is torqued to 48 to 55 N·m — a loose cam lets the mechanism slip without actually moving the deck. Check that the safety interlock (operator presence switch) isn't preventing lift activation by running through the OPC switch checks in the Electrical System section on page 106. The full mower lift fault procedure is on page 103.
Manual Section: Lift System TroubleshootingFrequently Asked Questions
What are the recommended service intervals?
The manual provides a detailed maintenance schedule indicating various checks and services to be performed at different operating hour intervals. For example, engine oil should be changed every 50 hours, and the air cleaner element should be checked every 50 hours and replaced every 200 hours. The spark plug should be checked every 100 hours.
What fluids and capacities does this machine require?
The machine requires 12.2 L (3.22 U.S. gals, 2.68 Imp.gals) of fuel. The engine crankcase requires 2.1 L (2.2 U.S.qts, 1.8 Imp.qts) of API Service Classification SF, SG, SH, SJ or SL SAE40 oil. The transaxle case requires 1.66 L (1.75 U.S.qts, 1.46 Imp.qts) of API Service Classification SL SAE20W-50 oil.
How to troubleshoot engine won't start?
If the engine won't start, check if the operator is on the seat, the parking brake lever is in the proper position, and the PTO switch is disengaged. Also, verify the main switch is in the "ON" position and check for fuel. If these are correct, further checks include the fuse, air cleaner, spark plug, and fuel hose/filter.
What are the hydraulic system specifications?
The hydraulic system for the transaxle has a maximum input speed of 3800 min⁻¹ (rpm) and a minimum input speed of 1800 min⁻¹ (rpm). The overall transaxle reduction is 19.2:1. The variable displacement pump has a maximum displacement of 10 cc/rev.
Is this Kubota Z122R-AU, Z122RKW-AU Workshop Manual a digital download?
You get a 153-page searchable PDF that downloads instantly after checkout. Open it on your laptop, tablet, or phone — bring it right to the shop floor.
Can I print specific sections of this Kubota Z122R-AU, Z122RKW-AU manual?
Yes, print as many copies as you want — there are no restrictions. Many mechanics print the section they need and bring it to the shop floor.
Does this Kubota Z122R-AU, Z122RKW-AU manual include hydraulic schematics?
Yes. The manual includes hydraulic circuit diagrams, system schematics, and component specifications with pressure ratings.
Document Quality
This document is a high-quality scanned PDF, featuring an OCR layer that allows you to search and copy the full text content. The text is consistently crisp and very easy to read across all pages. Diagrams and illustrations are clear raster images, and their labels are generally legible, though some fine details might soften slightly upon extreme zoom. The pages are clean, free from significant scan artifacts, stains, or skewed content, maintaining a professional appearance. Please note there are several blank pages interspersed throughout, typically used to delineate new sections.
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