The Craftsman Model 917.203900 is a riding lawn mower featuring a 42-inch cutting deck, 19.5 HP Briggs & Stratton engine, hydrostatic transmission, electric start, and rear-engine design. This manual provides detailed parts identification, diagrams, ordering information, and maintenance guidelines for the mower's major systems: engine, cutting deck, transmission, steering, electrical, and chassis. Below are key sections for parts overview, diagrams, ordering, assembly, maintenance, and troubleshooting.
This section provides exploded-view diagrams and part numbers for the Craftsman 917.203900. Diagrams are organized by assembly group.
| Diagram Section | Covered Components |
|---|---|
| Engine Assembly | Briggs & Stratton 19.5 HP engine, air filter, carburetor, muffler, fuel tank |
| Cutting Deck Group | 42-inch deck shell, blades, spindles, pulleys, belts, mandrels |
| Drive System | Hydrostatic transmission, drive belt, axle, rear wheels |
| Steering Assembly | Steering wheel, gear, tie rods, front wheels |
| Electrical System | Battery, starter, ignition switch, wiring harness, safety switches |
| Chassis & Frame | Main frame, seat, fenders, footrests, mounting brackets |
| Control Linkage | Throttle cable, brake linkage, deck lift mechanism |
| Fasteners | Bolts, nuts, washers, pins, clips specific to model |
Parts for the Briggs & Stratton 19.5 HP engine (Model 31P777-0143-G1).
WARNING! Disconnect spark plug before servicing engine. Use genuine Briggs & Stratton parts for optimal performance.
42-inch stamped steel deck parts list and diagram.
CAUTION! Ensure deck is properly supported when removing blades. Always balance blades after replacement.
Hydrostatic transmission (Peerless/ Tecumseh) and drive components.
| Part Description | Part Number | Notes |
|---|---|---|
| Hydrostatic Transmission | 917-XXXXX | Complete unit; service as assembly |
| Drive Belt | 144-9590 | Kevlar reinforced, 1/2" x 95" |
| Axle Assembly | 532-XXXXX | Includes axle, bearings, seals |
| Rear Tires | 20x10-8 | Turf tread, tubeless |
| Brake Assembly | 732-XXXXX | Disc brake, caliper, pads |
| Transmission Linkage | Control rod, springs, bushings | For speed and direction control |
Steering system and operator control parts.
Tip: Lubricate steering linkage periodically for smooth operation.
12-volt electrical system components.
WARNING! Disconnect battery negative terminal before electrical work to prevent shorts.
Frame, body panels, and structural components.
CAUTION! Inspect frame for cracks or damage regularly, especially after impacts.
Standard hardware used throughout the mower.
| Hardware Type | Size/Description | Typical Use |
|---|---|---|
| Hex Bolts | Grade 5, 1/4"-20, 5/16"-18 | General assembly |
| Nylock Nuts | 1/4", 5/16" | Vibration-prone areas |
| Washers | Flat & lock washers | Under bolt heads/nuts |
| Hairpin Clips | 1/8", 5/32" | Linkage retention |
| Spring Pins | 3/16" x 1" | Pivot points |
| Belleville Washers | For blade mounting | Blade retention |
How to order genuine Craftsman parts for model 917.203900.
Note: Some parts may be superseded by newer versions; dealer can provide latest part numbers.
Key assembly steps for major components (for service or after shipment).
WARNING! Torque all fasteners to specifications. Refer to service manual for detailed torque values.
Recommended parts replacement intervals.
| Component | Interval | Part to Replace |
|---|---|---|
| Engine Oil | Every 50 hours | Oil filter, gasket |
| Air Filter | Every 25 hours | Filter element |
| Spark Plug | Every 100 hours | Champion RC12YC |
| Mower Blades | Seasonally or when dull | Blades (pair) |
| Deck Belt | Every 2 years | Belt #144-9591 |
| Hydraulic Fluid | Every 500 hours | Transmission fluid |
| Battery | Every 3-4 years | 12V U1 battery |
Common problems related to parts and solutions.
| Symptom | Possible Faulty Part | Corrective Action |
|---|---|---|
| Engine won't start | Spark plug, fuel filter, battery | Replace spark plug; check fuel filter; test battery voltage. |
| Uneven cutting | Worn blades, bent mandrel | Replace blades; inspect and replace damaged spindle/mandrel. |
| Loss of drive power | Worn drive belt, transmission | Replace drive belt; check transmission linkage and fluid. |
| Excessive vibration | Unbalanced blade, loose pulley | Balance or replace blade; tighten or replace pulley. |
| Steering loose/wandering | Worn tie rod ends, steering gear | Replace tie rod ends; adjust or replace steering gear. |
| Deck won't lift | Broken lift cable, worn linkage | Replace lift cable; inspect and replace worn lift arms/brackets. |
Reset: For electrical issues, disconnect battery for 5 minutes to reset safety system.
Service Support: 1-888-331-4569; www.craftsman.com/parts