Part of the John Deere Repair Manuals.
John Deere's TM1678 strips the F620, F680, and F687 Z-Trak mowers down to the frame and builds them back, and this John Deere F620, F680, F687 technical manual PDF hands you all 366 pages of it. Electrical schematics and harness drawings claim roughly a third of the book, tracing every circuit from key switch to PTO clutch with diagnosis routines for each one. The hydrostatic power train gets its own hydraulic schematic plus pump rebuild and wheel motor repair procedures, and the Kohler CH20S and CH23S engine section runs from governor linkage to starting motor. Check PTO drive speed against the 3300 rpm spec, then torque the PTO clutch cap screw to 136 N-m (100 lb-ft). A number guessed off a forum can crack a clutch housing. Bookmarked and searchable by keyword, with serial number locations up front so your parts counter pulls the right numbers the first time.
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| General Specifications | 9-19 | Vehicle Specifications, Metric Fastener Torque Values, Metric Fastener Torque Values Grade 7, Inch Fastener Torque Values |
| Gasoline Specifications | 20-21 | 4-Cycle Engines North America, Gasoline Storage, 4-Cycle Engines Europe |
| Oils and Lubricants | 22-28 | 4-Cycle Gasoline Engine Oil North America, 4-Cycle Gasoline Engine Oil Europe, Break-In 4-Cycle Gasoline Engine Oil North America, Break-In 4-Cycle Gasoline Engine Oil Europe |
| Serial Number Locations | 29-30 | Machine Identification Number, Engine Serial Number, Mower Deck Serial Number |
| Engine (Kohler CH20S and CH23S) | 31-106 | Engine Specifications, Troubleshooting, Tests and Adjustments, Repair, Starting Motor |
| Electrical | 107-228 | Electrical Schematics, Wiring Harnesses, Circuit Operation, Diagnosis, Battery Test |
| Hydrostatic Power Train | 229-274 | Hydraulic Circuit Symbols, Power Train Operation, Troubleshooting, Hydraulic Pump Repair, Wheel Motor Repair |
| Brakes | 275-294 | Brake System Operation, Troubleshooting, Park Brake Adjustment, Disc Brake Repair, Drum Brake Repair |
| Attachments and Index | 295-366 | Mower Deck Troubleshooting, Mower Leveling, Gearbox Repair, Spindle Assembly, Index |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| All Models | ||
| PTO Drive Speed | 3300 ± 50 rpm | p. 12 |
| Engine Mounting Cap Screw (Bracket-to-Frame) Torque | 32 N•m (24 lb-ft) | p. 35 |
| Oil Filter Torque | 7.3 ± 1.7 N•m (65 ± 15 lb-in.) | p. 35 |
| Oil Drain Plug Torque | 13.6 N•m (10 lb-ft) | p. 35 |
| PTO Clutch Cap Screw Torque | 136 N•m (100 lb-ft) | p. 297 |
| Mower drive belt tension spring length | 133 mm (5.25 in.) | p. 312 |
| Engine Oil Capacity (With Filter) | 1.9 L (2.0 qt) | p. 11 |
| Hydraulic Oil Reservoir Capacity | 5.7 L (1.5 gal) | p. 12 |
| Spark Plug Gap | 1.02 mm (0.040 in.) | p. 35 |
| Flywheel Retaining Cap Screw Torque | 66.4 N·m (49 lb-ft) | p. 36 |
| F620 | ||
| Fuel Tank Capacity (F620) | 17 L (4.5 gal) | p. 12 |
| F680 and F687 | ||
| Fuel Tank Capacity (F680 and F687) | 26.5 L (7 gal) | p. 12 |
