Part of the Kubota Repair Manuals.
This is the Kubota Workshop Manual for the Z122E-AU, Z121S-AU, Z125E-AU and Z125S-AU zero-turn mowers, covering machines built around the GH731V-1, GH736V, GH733V-1 and GH750V engines. It runs 172 pages and is delivered as a downloadable PDF you can read on a phone, tablet or computer, or print for the shop.
The manual walks through the whole machine: engine structure and lubrication, the hydrostatic transaxle, front axle, lift system, the full electrical system with wiring diagrams, and the mower deck. You get identification details, troubleshooting, servicing specifications, tightening torques, and step by step disassembly and assembly.
With it you can diagnose a non-starting engine, service the electric PTO clutch, chase a weak drive side, level the deck, or rebuild a worn front caster, all backed by Kubota's own procedures and spec values.
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| Information | 4-15 | |
| General | 16-65 | Identification, Serial Number, Cylinder Number, General Precautions, Wiring, Battery, Fuse, Connector |
| Engine | 66-82 | Z122E, Z125E, Z121S, Z125S, Fuel System, Fuel Line, Lubrication System |
| Transaxle | 83-112 | Hydraulic Circuit, External Components, Inner Components, Parking Brake, Overall Transaxle Reduction, Separating Transaxle, Removing Control Lever Panel and Fuel Tank, Removing ROPS |
| Front Axle | 113-119 | Separating Front Wheel and Wheel Bracket, Front Wheels Wander to Right or Left, Flange Nut (Wheel), Bracket Bolt, Remove Wheel Bracket |
| Lift System | 120-127 | Cam Dial, Cam Shaft, Cam, Front Lift Shaft, Rear Lift Shaft, Link Stopper, Mower Link |
| Electrical System | 128-154 | Wiring Diagram, Start System and Opc, Start System, Operator's Presence Control, Safety Switches, Relay, Electrical Equipments |
| Mower | 155-172 | Power Transmission, Mower Deck, Anti-Scalp Rollers, Blades, Mower Belt, Tension Pulleys, Blade Shaft, Pulley Holder |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| All Models | ||
| General Use Screws, Bolts and Nuts (M6, No-grade or 4T) | 7.9 to 9.3 N·m | p. 27 |
| General Use Screws, Bolts and Nuts (M8, No-grade or 4T) | 18 to 20 N·m | p. 27 |
| Fuel tank capacity | 16 L | p. 26 |
| Engine crankcase (with filter) capacity | 1.8 L | p. 26 |
| Rated engine revolution | 3600 rpm | p. 13 |
| Engine crankcase oil capacity | 1.8 L | p. 13 |
| Transmission case oil capacity | 4.8 L | p. 13 |
| Z122E, Z125E | ||
| Engine oil change interval (Z122E, Z125E) | every 50 Hr or every 1 year | p. 30 |
| Z121S, Z125S | ||
| Engine oil change interval (Z121S, Z125S) | every 100 Hr | p. 31 |
| Z122E-AU | ||
| Max. engine power (Gross), Z122E-AU | 16.4 kw (22 HP) | p. 13 |
| Z121S-AU | ||
| Max. engine power (Gross), Z121S-AU | 15.7 kw (21 HP) | p. 13 |
| Z125E-AU, Z125S-AU | ||
| Max. engine power (Gross) (Z125E-AU, Z125S-AU) | 18.6 kw (25 HP) | p. 13 |
