Need factory numbers for your Bolens QS or QT garden tractor? This 93-page Bolens QS, QT, 1660, 1666, 1900, 1966 service manual PDF (OEM #552974-2) walks you through the hydrostatic drive, transaxle, and PTO clutch on the QT-16, QS-16, and QT-17 as well. You get wiring diagrams broken out by serial number range, so an early 1660 gets its own charging and light circuits instead of a close-enough guess. Inside: hydro repair for both Eaton and Sundstrand units, carburetor adjustments, interlock switch checks, plus mower deck, snow thrower, and tiller service. Set the Kohler idle on a 1660 to 2350 RPM; the Onan in a 1666 runs 1900. Swap-meet parts, forum threads, faded memories: none of them beat the factory book. Bookmarked PDF opens on laptop, tablet, or phone; carry it out to the barn and get it running this season.
What's Inside This Bolens QS, QT & 1900 Series Manual
| System | Pages | Key Topics |
|---|
| General | 1-9 | Serial Number Information, Specifications, Maintenance Chart, Lubrication Points, Lubrication Chart |
| Electrical System | 10-28 | Troubleshooting Guide, Electrical Wire Color Guide, Wiring Diagrams, Light Circuit, Charging Circuit, PTO Clutch Circuit, Seat Switch Circuit |
| Drive Train | 29-58 | Troubleshooting Guide, Hydrostatic Transmission, Hydrostatic Identification, Transaxle Removal, Oil Seal Installation, Bearing Installation, Hydro Installation |
| Fuel System | 59-64 | Troubleshooting Guide, Servicing (Fuel Valve, Duel Valve, Fuel Filter, Air Cleaner, Carburetor Adjustments) |
| Chassis | 65-74 | Steering Assembly, Hydrostatic Adjustments, Brake Assembly, Interlock Switches, Power Take-Off |
| Hydraulic System | 75-80 | Trouble Shooting Guide, Testing Hydraulic System, Hydraulic Power Lift |
| Engine | 81-85 | Troubleshooting Guide, Qt-16 Onan Engine, Qs-16 Kohler Engine, Qt-17 Kohler Engine |
| Tractor Attachments | 86-93 | Mower Decks, Snow Thrower, Tillers |
Quick Reference Specifications
| Specification | Value | Page |
|---|
| All Models |
| Battery voltage | 11.5 to 12.5 volts | p. 27 |
| Transmission Oil Capacity | 10 quarts | p. 6 |
| Transaxle Housing Capscrew Torque | 30 ft-lbs | p. 49 |
| Front Tire Pressure | 12 PSI | p. 86 |
| Rear Tire Pressure | 8 PSI | p. 86 |
| 1666 |
| Onan engine idle speed | 1900 RPM | p. 62 |
| Engine Oil Capacity (Model 1666) | 3 pints | p. 5 |
| Engine Oil Capacity (Model 1666 Onan) | 2 quarts | p. 6 |
| 1660 |
| Kohler 1660 idle speed | 2350 RPM | p. 63 |
