1999 John Deere Mid-Mount Ztrak M653/M655/M665 Mower Technical Manual (P/N TM1778)

John Deere Technical Manual TM1778, September 1999 edition, covers the M653, M655, and M665 Mid-Mount Ztrak mowers, serial numbers 010001 and up, with system diagnosis and repair procedures.

• Kohler engine repair: Engine removal, cylinder-head and valve service, camshaft timing, piston and crankshaft inspection, and hydraulic lifter priming and bleeding.

• Engine testing and fuel system: Troubleshooting charts, cylinder leakdown and crankcase vacuum tests, fuel-flow checks, carburetor overhaul, and float-level adjustment.

• Electrical and PTO: Wiring diagrams, component-location views, charging and interlock diagnostics, starting motor repair, and electric PTO clutch replacement and break-in.

• Hydrostatic drive: Hydraulic pump and wheel motor disassembly, inspection and assembly, system bleeding, neutral linkage adjustment, and reverse spring detent checks.

• Mower deck service: Deck removal and leveling, drive-belt replacement, blade sharpening and balancing, spindle repair, and jacksheave assembly service.

• Brakes and chassis: Park brake diagnosis and adjustment, brake band and hub replacement, linkage repair, caster wheel service, and seat platform removal.

John Deere wrote this technical manual for experienced technicians.

Kohler Engine Testing and Internal Repair

Fault isolation: Cylinder leakdown testing with the JT-03502 test kit helps distinguish leakage at the rings, intake valves, and exhaust valves before teardown. Oil-pressure and spark tests address lubrication and ignition faults.

Internal repairs: The CH22S and CH25S sections include valve-seat reconditioning, cylinder deglazing and reboring, timing-mark alignment, and internal wear limits. The hydraulic lifter instructions explain how improper preparation before startup can damage push rods or rocker arms.

Carburetor differences: The exploded view identifies accelerator-pump parts used only on the CH25S. CARB/EPA carburetor adjustment is restricted to authorized, factory-trained technicians, and the main jet has no fast-idle adjustment.

Electrical Circuits and PTO Service

The Electrical Schematic, W1 Main Wiring Harness, and separate operator-on-seat and operator-off-seat run-circuit diagrams accompany test-location tables. Normal readings and follow-up checks support fault tracing through the start, brake, and run relays.

Starter repair includes brush replacement and armature testing. PTO clutch coverage consists of circuit diagnosis, removal, installation, and break-in; the break-in procedure is designated dealer-only.

Hydraulic Pump and Wheel Motor Repair

The Hydraulic System Schematic, Hydraulic System Hose Routing views, and JIC circuit-symbol reference explain the separate pump and motor circuits. Symptom charts address poor tracking, loss of drive, sluggish operation under load, and excessive noise.

Pump repair extends to the charge pump, check valves, cylinder block, swashplate, and displacement control shaft. The assembly instructions flag misalignment that can damage the end-cover and cylinder-block sealing surfaces.

Wheel motor inspection covers the commutator, rotor set, wear plate, coupling shaft, and bearings. Wheel motor repair is limited to seals, seal rings, and the outer bearing; damage to other parts calls for replacement of the complete motor.

Always verify your lift equipment ratings and relieve hydraulic pressure before opening lines to ensure a safe shop environment.

Deck Spindles, Jacksheaves, and Park Brakes

Spindle cross-sections and exploded jacksheave views show bearing, seal, spacer, and sheave arrangements. Deck adjustment covers both leveling directions and lift-spring tension, with the TY15272 blade-height gauge specified for leveling checks.

The brake section distinguishes hydrostatic service braking from the separate band-type parking brakes. It covers linkage adjustment, lining inspection, and brake drum/wheel hub removal.

A Preview of Engine Torques and Ignition Clearances

These examples are a small selection of the engine specifications supplied with the repair procedures.

For the CH22S and CH25S, the staged cylinder-head tightening procedure ends at 40.7 N·m (30 lb-ft); the flywheel retaining screw specification is 66.4 N·m (49 lb-ft).

Ignition-module adjustment includes a final air-gap range of 0.203–0.305 mm (0.008–0.012 in.). Separate tables cover fluid capacities and standard and metric fastener torques.

Searchable Text, Bookmarks, and Diagram Views

Finding procedures and circuit details: Searchable PDF text and embedded bookmarks provide access to system chapters and individual procedures. Small labels on the wide electrical schematics are best read with zoom; split-page diagram views are also included.

The download is one printable 264-page PDF: 244 numbered manual and index pages, one cover, one machine illustration page, and 18 additional split-page diagram views. Six intentionally blank notes pages are already included in the numbered-page total.