1983-1999 Bolens QS-16, QT-16, QT-17 & 1900 Series Factory Service Manual (P/N 552974-2)

• Covers 1983–1999 Bolens QS-16, QT-16, QT-17, and 1900 Series tractors (including 1660, 1666, and 1966 variants).
• Official 93-page Bolens publication Form 552974-2 (4/83), superseding earlier edition 552974-1.
• Features 56 detailed exploded-view diagrams and 15 electrical wiring schematics.
• Serves as the primary technical reference for the entire QS, QT, and 1900 tractor line lifespan.

Tractor Systems and Maintenance Documentation

When bringing a classic Bolens utility tractor back to factory spec, having the exact component teardown sequence is critical. This publication provides the necessary reference data for deep-dive mechanical restoration and standard maintenance. Organized into eight primary groups, the document breaks down electrical systems, hydrostatic drive trains, chassis configurations, fuel systems, engines, and attachment gear cases. You get clear technical overviews on troubleshooting starter circuits, inspecting the charge pump, adjusting transaxle assemblies, and maintaining the P.T.O. brake. Maintenance charts outline the exact factory intervals for cooling screens, spark plugs, breather elements, and hydraulic fluid flushes. Before beginning any teardown or diagnostic work on these systems, always verify your shop equipment is properly rated for the tractor's weight and disconnect the battery to prevent accidental engagement.

Specification and Reference Data

Accurate numbers separate a reliable rebuild from a comeback. The reference tables inside outline crucial tolerances, such as transaxle carrier assembly bolt torque values (25–30 ft. lbs. / 34–40 N.m) and the exact 10-quart capacity for the hydrostatic transmission. Electrical reference values for the 1666 and 1966 models clearly state a 12 VDC clutch voltage paired with a 4.7 amp current draw. The factory workshop documentation also details engine parameters, listing valve clearance at 0.15 mm (0.006 in) and spark plug gaps at 0.25 mm (0.010 in). Note that this overview describes the contents of the reference material and does not provide step-by-step repair instructions.