Kubota AT55 Walk-Behind Tiller Service Manual
This service manual is the workshop repair reference for the Kubota AT55 walk-behind tiller and its Kubota GS200-2T gasoline engine, running roughly 88 pages split into two parts — "Mechanism" and "Disassembling and Servicing." It's a true service manual — component-level teardown and repair, not just operation — covering construction and function of each tiller section first, then troubleshooting, servicing specifications, checking and adjusting, and disassembly and assembly, backed by factory specifications, allowable limits, tightening torques, and a special-tools reference. Originally published by Kubota and delivered here as an instant PDF download you can read on any device or print for the bench.
Models covered: Kubota AT55 walk-behind tiller
About the Kubota AT55
The AT55 is a walk-behind rotary tiller powered by the Kubota GS200-2T — a forced air-cooled, four-cycle, single-cylinder, side-valve gasoline engine of 201 cc (12.3 cu. in.) with a 69 × 54 mm bore and stroke, rated at 3.8 HP continuous at 1800 rpm and 5.2 HP maximum. The engine carries a maintenance-free, transistor-controlled, pointless magneto ignition system, a cyclone-type air cleaner, a horizontal butterfly-valve carburetor, a centrifugal flywheel governor, splash lubrication, and a recoil starter.
Power runs through a pulley-and-V-belt drive to a four-speed forward, two-speed reverse auxiliary transmission (shifted by relocating the V belt on the pulleys) and a gear-and-chain main transmission (shifted by lever), with a belt-tension main clutch controlled by a deadman grip. The rotor spins 24 tines at 360 mm (14 in.) diameter for a tilling width of 660 mm (26 in.) or 920 mm (36 in.) and a maximum tilling depth of 180 mm (7 in.). These machines earned their keep on small farms and market gardens, and a great many remain in active service — which is exactly why a complete factory service reference still matters when a repair goes past routine maintenance.
What This Manual Covers
- Specifications & dimensions: Full engine, power-transmitting-system, tiller, and rotor specifications, plus dimensioned drawings for the machine, PTO, rear hitch, and axle.
- Engine mechanism: Features of the GS200-2T, intake and exhaust (cyclone air cleaner and muffler), fuel system (carburetor main and slow circuits, governor), and ignition system (magneto ignition, high-voltage generation principle, transistor magneto ignition principle, engine stop switch).
- Transmission mechanism: Construction and function of the auxiliary transmission and main transmission.
- Handlebar mechanism: Handlebar and lockout device construction and function.
- General service section: Tiller identification, general precautions, lubricants, tightening torques, maintenance check list, check and maintenance, and special tools.
- Separation: Draining transmission oil and separating the engine and transmission case for disassembly and assembling.
- Engine servicing: Troubleshooting, servicing specifications, tightening torques, and checking/disassembling/servicing of the engine body, fuel system, ignition system, and recoil starter.
- Transmission servicing: Troubleshooting, servicing specifications, and checking/disassembling/servicing of the auxiliary and main transmissions.
Why This Manual Matters
- Component-level repair, not just operation. This is a workshop service manual — it walks through separating the engine from the transmission case and tearing down the engine body, fuel system, ignition, recoil starter, and both transmissions.
- The reference data the job depends on. Servicing specifications, factory specifications with allowable limits, and tightening torques are included, so you can reassemble to spec rather than guess.
- Carburetor and ignition detail you won't find elsewhere. The manual documents the carburetor's main and slow circuits jet by jet, and explains the transistor-controlled pointless magneto ignition — the model-specific detail generic guides don't carry.
- Mechanism-first structure. Each section explains construction and function before service, so you understand the system before you open it up.
- Long service life, scarce documentation. These walk-behind tillers are still working machines, but factory literature is increasingly hard to find — this searchable, restored PDF puts the complete manual back in your hands.
Manual Code: 606020