Kubota built OEM #9Y111-16030 to cover five AU-B generators under one cover: the SQ-1120B-AU-B, SQ-1150B-AU-B, SQ-3140B-AU-B, SQ-3200B-AU-B, and SQ-3300B-AU-B. Wiring diagrams trace both the generator circuit and the engine circuit, and exploded-view assemblies run throughout. Sixty-three pages walk the disassembly and rebuild of the D1703-EBG, V2203-EBG, and V3300-EBG engines step by step. Beyond that you'll find tightening torque tables, AVR adjustment procedures, a maintenance checklist running from 50-hour to 2-year intervals, and engine circuit troubleshooting for voltage and load faults. Output spans 11.2 kVA on the SQ-1120B-AU-B up to 30 kVA on the SQ-3300B-AU-B, with oil capacity from 5.6 L to 13.2 L by model. Search any spec by keyword and read it right at the machine.
What's Inside This Kubota SQ-1120B-AU-B & variants Manual
| System | Pages | Key Topics |
|---|---|---|
| Information | 3-12 | Safety First, Safety Decals, Specifications, Dimensions |
| General | 13-38 | Handling Precautions for Electrical Parts and Wiring (Battery, Fuse, Connector, Handling of Circuit Tester, Color of Wiring), Lubricants, Fuel and Coolant, Tightening Torques |
| Engine | 39-132 | Troubleshooting, Servicing Specifications (D1703-Ebg, V2203-Ebg, V3300-Ebg), Tightening Torques |
| Generator | 133-159 | Generating Method (Principle of Operation), Structure (Stator, Exciter, Rotor, Avr) |
| Servicing | 160-181 | Troubleshooting (Engine Circuit Troubleshooting), Servicing Specifications, Tightening Torques, Checking |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| SQ-1120B-AU-B, SQ-3140B-AU-B | ||
| Engine oil capacity | 5.6 L | p. 22 |
| SQ-1150B-AU-B, SQ-3200B-AU-B | ||
| Engine oil capacity | 7.6 L | p. 22 |
| Cooling System Capacity | 7.4 L | p. 22 |
| SQ-1120B-AU-B | ||
| Generator Output | 11.2 kVA (11.2 kW) | p. 10 |
| SQ-3300B-AU-B | ||
| Generator Output | 30 kVA (24 kW) | p. 10 |
| Engine Oil Capacity | 13.2 L | p. 22 |
| All Models | ||
| M10 Bolt Tightening Torque (No-grade or 4T) | 40 to 45 N·m | p. 23 |
| Fuel Injection Nozzle Injection Pressure Factory Specification | 13.73 to 14.71 MPa | p. 49 |
| Alternator Regulating Voltage Factory Specification | 14.2 to 14.8 V | p. 50 |
| D1703-EBG, V2203-EBG | ||
| Cylinder Head Surface Flatness Allowable Limit | 0.05 mm | p. 45 |
| Valve Clearance Factory Specification | 0.18 to 0.22 mm | p. 45 |
| Starter Commutator O.D. Factory Specification | 30.0 mm | p. 50 |
Kubota SQ-1120B-AU-B & variants Common Problems This Manual Covers
Kubota SQ-1120B-AU-B diesel generator engine cranks but won't fire, no start after repeated attempts
Start with fuel level, then clean the water separator on its 100 Hr schedule (page 24). Confirm the 10A, 3A, and 2A slow-blow fuses in the fuse circuit are intact. When the starter engages but the engine won't fire, test injection nozzle pressure against the 13.73 to 14.71 MPa factory spec (page 49).
Manual Section: Engine Troubleshooting (General)Generator output voltage drops or fluctuates heavily under load, circuit breaker trips p. 133
Inspect the circuit breaker for tripped or damaged contacts. Verify AVR connections in the Generator section (page 139). Confirm stator mounting screws sit at 19.6 to 24.5 N·m per page 172. If voltage keeps hunting or fails to rise, measure rotor, exciter, and stator winding resistance and test alternator charging output.
Manual Section: Generator Troubleshooting (Electrical System)Engine coolant temperature alarm triggers during sustained load operation, unit shuts down
Verify coolant level and inspect radiator hoses and clamps for leaks; water pipes get replaced every 2 years (page 24). Clean radiator fins, check the fan belt, and swap the belt at 800 Hr (page 24). Work through the engine overheating troubleshooting steps, and top up with the correct LLC concentration.
Manual Section: Generator Troubleshooting (General)Excessive black or white exhaust smoke during startup or operation under load
Read the smoke color first: black points to air restriction or over-fueling, white indicates coolant ingestion, blue signals oil burning. Clean the air cleaner element every 100 Hr and replace it yearly (page 24). Check injection nozzles at 1500 Hr intervals; factory pressure is 13.73 to 14.71 MPa (page 49).
Manual Section: Engine Troubleshooting (General)Engine oil pressure warning activates shortly after startup, unit performs emergency stop
Shut the engine down at once. Check oil level and top up: SQ-1120B-AU-B and SQ-3140B-AU-B take 5.6 L; SQ-1150B-AU-B and SQ-3200B-AU-B take 7.6 L; SQ-3300B-AU-B takes 13.2 L (page 22). Confirm oil switch torque at 14.7 to 19.6 N·m (page 56). Change oil every 200 Hr, first at 50 Hr (page 24), and check for leaks before restarting.
Manual Section: Generator Troubleshooting (General)Battery drains rapidly between generator uses, starter motor turns over slowly or fails p. 50
Measure alternator charging voltage against the 14.2 to 14.8 V factory spec (page 50). Clean the battery terminals and inspect them on the 100 Hr schedule (page 24). Batteries get replaced every 2 years (page 24). If output reads in spec but the battery still drains, trace the wiring for shorts or parasitic draws using the engine circuit diagram.
Manual Section: Engine Troubleshooting (General)Frequently Asked Questions
What are the recommended service intervals?
Intervals run from daily checks to the initial 50 hours, then every 100, 200, 400, 800, and 1500 hours, plus a 2-year mark for certain components. Engine oil, for instance, gets checked daily and changed every 200 hours, while radiator coolant is changed every 2 years.
What fluids and capacities does this machine require?
This machine calls for specific lubricants, fuel, and coolant. Engine oil should be API class higher than CD: SAE10W-30, SAE10W-40, or SAE30 above 25 °C. Fuel is Diesel fuel No. 2-D. Capacities vary by model; the SQ-1120B-AU-B, for example, holds 5.6 L of engine oil, a 72 L fuel tank, and a 6.6 L cooling system.
How to troubleshoot engine won't start?
When the engine won't start, the usual culprits are no fuel, air or water in the fuel system, a clogged fuel pipe or filter, or fuel and oil too thick at low temperatures. Fixes range from replenishing fuel and venting air to cleaning or changing fuel components, switching to specified fuel and oil, or tightening the injection pipe nuts. On the electrical side, look for a discharged battery, a faulty starter or key switch, or disconnected wiring.
What torque specifications are listed?
Torque values are listed component by component. A general-use M6 bolt (Ordinariness 4) takes 7.9 to 9.3 N·m (0.80 to 0.95 kgf·m). On the engine, the cylinder head screw (D1703-EBG, V2203-EBG) runs 93.2 to 98.0 N·m (9.5 to 10.0 kgf·m) and the flywheel screw 98.1 to 107.8 N·m (10.0 to 11.0 kgf·m). For the generator, the rotor mounting screw is 24.5 to 34.3 N·m (2.5 to 3.5 kgf·m).
How quickly can I access this Kubota SQ-1120B-AU-B & variants manual after?
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Are there any print restrictions on this Kubota SQ-1120B-AU-B & variants manual?
None. Print as many copies as you like. Plenty of mechanics run off just the section they need and carry it onto the shop floor.
Can I find wiring schematics in this Kubota SQ-1120B-AU-B & variants manual?
It does. This Kubota SQ-1120B-AU-B and variants Workshop Manual carries full electrical wiring diagrams, wire routing, and connector pinouts.
Document Quality
This document is a scanned PDF with an excellent OCR layer, allowing you to search and copy the full text content. The OCR text is crisp and very easy to read throughout the manual. Diagrams and illustrations are raster images, but their labels and details are generally clear and readable, even when zoomed in. Pages are clean with no scan artifacts, stains, or skewed content. Please note that pages 3 and 13 are intentionally blank, serving as section dividers.
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