Part of the Kubota Repair Manuals.
This is the Kubota GL Series Diesel Generator Workshop Manual, the factory service manual for the GL3500, GL4500, GL4500-S, GL5500, GL5500-S, and GL6500-S generator sets. These units are built on Kubota's ZB400-GL through ZB600-GL(S) diesel engines in both quiet-type and heavy-duty configurations.
The manual covers the generator mechanism, including the stator and rotor assemblies and the automatic voltage regulator (AVR), along with engine service, the cooling system, servicing specifications, and tightening torques. Troubleshooting and maintenance sections walk through the checks that keep these sets starting and holding output.
For an owner, standby-power installer, or independent technician, this PDF download provides the specifications and repair procedures to diagnose a no-start, chase down low or unstable voltage, and service the engine to factory values. It is text-searchable and prints on standard paper.
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| Cover Page | WSM Logo, Workshop Manual, Diesel Generator, Gl Series, Kubota | |
| Specifications | Generator Gl-S Series (2 Poles), Engine Zb400-Gl-S, Zb500-Gl-S, Zb600-Gl-S, Generator Gl Series (4 Poles), Engine Zb400-Gl, Zb500-Gl, Zb600-Gl | |
| Mechanism | F Feature, Generator Units (Quiet Type Series, Heavy Duty Series, Stator Assembly, Rotor Assembly, Avr), Avr (Bias Current Path, Excitation Current Path From the Sub Coil to Rotor) | |
| Back Cover | Kubota Tractor Corporation, Corporate Office, Western Division, Central Division, Northern Division, Southeast Division, Printed in U.S.A., June 2002 |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| GL3500, GL4500-S | ||
| Cylinder, Head Bolt torque | 39.2 to 44.1 N-m (4.0 to 4.5 kgf-m, 28.8 to 32.5 ft-lbs) | p. 38 |
| Connecting Rod Bolt torque | 14.7 to 18.6 N-m (1.5 to 1.9 kgf-m, 10.8 to 13.7 ft-lbs) | p. 38 |
| All Models | ||
| Fuel filter cleaning interval | Every 150 hours | p. 40 |
| Fuel filter changing interval | Every 1000 hours | p. 40 |
| Air cleaner cleaning interval | Every 75 hours | p. 40 |
| Compressed air pressure for cleaning air cleaner element | under 686 kPa (7 kgf/cm2, 99 psi) | p. 43 |
| Solenoid coil resistance (Normal) | Approx. 2.0 Ω | p. 58 |
| Solenoid coil resistance (Defective) | Approx. 0.5 Ω | p. 58 |
| Water Pump Link-Belt checking interval | Every 200 hours | p. 40 |
| Generator V-Belt checking interval | Every 200 hours | p. 40 |
| GL4500-S | ||
| Battery model | 36B20R(S) | p. 8 |
| Battery capacity 20 HR | 12V-35AH | p. 8 |
