CRAFTSMAN 917.273640 Service Manual

Overview and safety considerations The Craftsman 917.273640 is a lawn mower with specific service requirements that demand careful attention to safety and procedure. Before performing any maintenance or repair, ensure the engine is completely off, the spark plug is disconnected, and the battery is isolated if applicable. Stabilize the mower on a flat, dry surface and engage any parking brakes or blade-disengagement mechanisms to prevent accidental movement or blade rotation during service. Review the machine’s model number and confirm that replacement parts match the 917.273640 designation to avoid compatibility issues that could compromise performance or safety. Familiarize yourself with the operator’s manual and the service manual to understand torque specifications, lubrication points, and recommended intervals for inspection and replacement of wear items. Safety cautions and personal protective equipment essentials Personal protective equipment is a critical component of safe maintenance. Always wear safety glasses or a faceshield to protect against flying debris when inspecting belts, blades, or cutting components. Use cut-resistant gloves when handling sharp blades and exposed metal edges, and don durable clothing that covers arms and legs to minimize skin exposure to moving parts. When working around the cutting deck, use a tool to prevent any accidental contact with sharp blades, and never reach into the blade area while the engine is powered or the blade remains engaged. It is essential to work in a well-lit, ventilated area free of ignition sources when refueling or testing the mower. If fuel spills occur, promptly clean with an absorbent material and dispose of it according to local hazardous waste guidelines. Required tools and maintenance environment A well-equipped maintenance area is indispensable for safe and effective service of the 917.273640. Gather standard hand tools such as sockets, wrenches, pliers, a torque wrench with appropriate range, and a flat-blade screwdriver for fastener access. For engine-related work, include a spark plug socket, a torque spec gauge, and a compression tester if required by the diagnosis. A clean, organized workbench with labeled containers for bolts and small parts helps prevent misplacement and reassembly errors. Lighting should be sufficient to clearly view underside components, and a stable, non-slip mat or lift can assist in raising the mower safely for deck and undercarriage inspections. Ensure you have a fire extinguisher rated for electrical and fuel fires nearby and that all tools are in good condition, with handles free of cracks and blades sharpness checked to avoid injury during disassembly and reassembly.

Engine system and fuel management The engine system of the CRAFTSMAN 917.273640 combines a compact, air-cooled powerhead with a fuel delivery and lubrication scheme designed for reliable operation in yard and light-duty tasks. A thorough understanding of the components, their interactions, and the signs of wear or improper configuration is essential for safe operation and long service life. Begin with a careful visual inspection of the fuel lines, clamps, and the carburetor mounting area for any signs of cracking, leaks, or loose connections. Note that heat from the muffler area can degrade rubber hoses over time, so any softening, hardening, or swelling warrants replacement. Pay particular attention to the recoil starting system, as a hard pull can indicate a misalignment or a binding linkage that may affect the engine’s ability to reach the proper starting RPM. Engine system overview and troubleshooting The fuel-and-air mixture is controlled by the carburetor, which meters fuel based on air drawn through the intake and controlled by the throttle linkage. When troubleshooting, begin with simple checks: ensure the fuse or kill switch circuit is intact, confirm that the fuel valve is open, and verify the presence of clean, fresh gasoline with an appropriate octane rating. If the engine attempts to start but runs poorly or stalls, inspect the air filter for restriction, the spark plug for fouling or improper gap, and the muffler for carbon buildup that could impede exhaust flow. A common issue in engines of this model is carburetor varnish from old fuel; in such cases, a careful cleaning or rebuild with manufacturer-approved parts is often necessary. If starting becomes chronically difficult, verify compression with a gauge and check for scored cylinders or worn piston rings, which can indicate deeper mechanical wear requiring professional service. Fuel system maintenance and service procedures Maintaining the fuel system involves regular inspection of the fuel tank, lines, primer bulb, and carburetor. Drain and replace old fuel to prevent varnish formation, especially if the unit has sat idle for extended periods. Inspect the fuel filter for clogs or deterioration and replace it at recommended intervals. When servicing the carburetor, remove and clean all passages with an approved solvent, ensuring jets are free of obstruction and reinstall the metering assembly to the correct orientation. Reconnect the fuel line clamps securely and check for any signs of fuel leaks around the tank cap, lines, and fittings. For optimal performance, ensure the idle speed and high-speed mixtures align with the manufacturer’s specifications, adjusting only with the appropriate tools and after confirming engine temperature is within the normal operating range. After any fuel system service, perform a careful leak test and verify that the engine starts smoothly and runs across the full throttle range. Lubrication and cooling system care The lubrication of moving parts in this engine relies on a properly mixed fuel-oil solution when applicable and on the lubrication schedule specified by the manufacturer for components such as the crankcase and any gear reductions. Verify that the oil fill level is within the recommended range and inspect the oil for signs of contamination, such as fuel dilution or metal particulates, which indicate internal wear or improper mixing. The cooling system relies on air flow around the cylinder and cooling fins; keep these fins clean and free of debris to prevent overheating during prolonged use. Regularly inspect the muffler and cooling shrouds for cracks or obstructions, ensuring that cooling paths remain unobstructed by grass buildup or dirt. If overheating occurs, allow the engine to cool and recheck that the air intake is clear, the spark plug remains correctly gapped, and that the carburetor is not delivering an excessively rich fuel mixture, which can generate additional heat. Proper lubrication and cooling together contribute to extended engine life and more consistent performance under load.

Electrical and charging system

The electrical system of the Craftsman 917.273640 is designed to supply reliable power to the engine starting, charging, and accessory circuits while withstanding the vibrations and environmental conditions typical of outdoor power equipment. A solid understanding of the fundamentals, including voltage, current flow, and continuity, helps diagnose issues quickly and prevent further damage. Begin with a visual inspection of connectors, harnesses, and protective covers to identify signs of wear, corrosion, or pin displacement that could disrupt electrical performance. Familiarize yourself with the typical color codes and connector polarities used in this model to ensure accurate testing and safe service practices. Maintaining clean, dry, and tight connections is essential for consistent operation and prevents intermittent faults that can be mistaken for more complex failures.

Electrical system fundamentals encompass the path from the battery through the starter solenoid, ignition switch, and charging alternator or stator, returning to ground. The charging system is designed to replenish battery capacity during operation while the engine is running, and it relies on a properly functioning stator, regulator, and wiring harness. A schematic overview helps technicians trace circuits such as ignition, charging, kill switch, and safety interlocks. Use a multimeter to measure battery voltage at rest and with the engine running to assess alternator output, ensuring it stays within the manufacturer’s specified range. Always verify ground integrity, as high resistance to ground can masquerade as several distinct electrical problems in this machine.

Battery, charging system, and wiring harness inspection focuses on protecting the power supply for starting and running. Inspect the battery for proper electrolyte levels, terminal cleanliness, and secure mounting; a swollen or leaking battery indicates internal failure and requires replacement. Examine the charging system for correct voltage output, typically around 12 to 14 volts when the engine operates, and check the regulator for heat damage or buzzing sounds that suggest internal faults. Wiring harnesses should be checked for insulation wear, fraying, exposed conductors, and correct routing to avoid chafing during operation. Pay particular attention to connections at the battery terminals, starter solenoid, ignition switch, and safety switches, since a poor connection at any point can cause no-start conditions or erratic engine behavior. When performing inspections, disconnect the battery before handling harnesses to prevent accidental short circuits and to reduce the risk of arcing or personal injury.

Troubleshooting common electrical faults involves a methodical approach to isolate the fault without replacing components unnecessarily. Start with a visual and tactile inspection of all battery connections and grounds, ensuring clean, tight, and corrosion-free terminals. If the engine won’t start, verify battery voltage, starter resistance, and the integrity of the ignition switch and kill switch circuits. For charging faults, check the alternator or stator windings, rectifier if present, and the regulator assembly for signs of overheating or contamination. Use a schematic-guided test to confirm continuity across harness segments and to locate any shorted or open circuits. Document the observed symptoms, perform measured voltage checks at successive points along the circuit, and compare readings to the factory specification to determine whether a component replacement or wire repair is necessary. In every troubleshooting step, practice safe service procedures, including disconnecting the battery when testing or adjusting electrical components and wearing appropriate eye and hand protection to mitigate the risk of shock or injury.

The starting procedures for the CRAFTSMAN 917.273640 require a careful sequence to ensure safe and reliable operation. Begin by inspecting the overall condition of the equipment, including the spark plug, air filter, fuel system, and lubrication levels. Make sure the fuel tank is filled with fresh, clean gasoline and that the choke or primer system is functioning correctly. When preparing to start, place the machine on a firm, level surface and engage any safety guards or shields as required. If the engine is cold, allow the battery to reach a proper charge and ensure the ignition switch is in the correct run position before attempting to start. Follow the manufacturer’s recommended starting method, whether it is a manual pull start, an electric start, or a combination system, and avoid excessive cranking to prevent unnecessary wear on the starter components.

Once the engine fires, monitor the initial RPMs and listen for any unusual noises or vibrations that could indicate a mechanical issue. Allow the engine to warm up to an operating temperature before placing it under load, and avoid rapid throttle changes during this warm-up phase. Check that the exhaust is emitting a normal tone and that there are no signs of exhaust leaks. During the startup sequence, verify that all safety interlocks and controls are functioning correctly, including blade engagement mechanisms if applicable. If the engine fails to start after several attempts, perform a quick verification of fuel delivery, spark, and compression, and consult service guidelines to determine if additional diagnostics are necessary.

Idle speed and throttle adjustment should be performed with the engine at its designated operating temperature and with the machine secured on a stable surface. With a properly calibrated idle, the engine should maintain stable RPM without stalling when under light load. Adjust the idle speed using the specified screws or adjustment mechanisms while monitoring the tachometer if available, and ensure there is no excessive fuel or air leakage around the carburetor. Make small adjustments and test the engine response by applying a light throttle, confirming that the transition from idle to run is smooth and free from hesitation. Always re-check the idle setting after performing any adjustments, and record the current specifications for future reference to maintain consistent performance across maintenance cycles.

Performance diagnostics and tuning procedures involve a methodical assessment of ignition, fuel, air, and exhaust systems. Use a diagnostic tachometer to verify that the engine is achieving the manufacturer’s target RPM under load, and verify that the governor or speed control system responds accurately to throttle input. Inspect the carburetor for proper fuel metering, idle mixture, and any signs of varnish or buildup, and perform appropriate cleaning or overhaul if performance deviations are observed. Check the air filter for obstruction and replace it if necessary to ensure optimal air intake. Examine the exhaust pathway for signs of restriction or leakage, and verify that the muffler and catalytic components (if equipped) are functioning as designed. Document any anomalies and follow the prescribed repair or tuning procedures to restore peak performance while preserving engine longevity.

In all procedures, follow safety guidelines by disconnecting power before servicing electrical components and employing appropriate personal protective equipment. Maintain clean work areas and organize removed parts with clear labeling to avoid misassembly. Use only manufacturer-approved parts and lubricants to ensure compatibility with the engine design and emissions standards. When in doubt, consult the official service documentation or a certified technician to prevent accidental damage and to guarantee that the machine complies with warranty requirements. Regular maintenance intervals should be established based on usage hours, operating conditions, and observed performance trends to sustain reliable operation of the CRAFTSMAN 917.273640.

The drive system of the Craftsman 917.273640 is a key interface between the engine and the wheels, translating the engine’s power into forward motion while allowing for controlled speed and braking. Begin by visually inspecting the entire drive path for signs of wear, cracks, or looseness in mounts, belts, pulleys, and the tensioning apparatus. Check for oil contamination, fraying, or missing debris that could indicate misalignment or impending failure. Carefully measure belt deflection and compare against the specification for installed belt length and tension to ensure proper engagement. Rotate the drive components by hand to feel for binding, unusual noise, or roughness that might indicate bearing wear or misalignment. Ensure all fasteners are tight to the manufacturer’s recommended torque values and that guards or covers are securely in place to prevent belt interference or personal injury.

The transmission in this model uses a V-belt drive that connects the engine pulley to the driven pulley, transmitting torque with configurable tension. When servicing the transmission, start with removing the belt guard and inspecting the belt for cracks, glazing, or chunking of the material. Replace the belt if any signs of wear are present, and use only the correct belt type and width specified for the 917.273640. Inspect the pulleys for grooves, burrs, or glazing that could contribute to belt wear or slipping, and deburr any sharp edges. After installing a new or renewed belt, verify proper belt tension, ensuring that the belt deflects within the recommended range when pressed midway between pulleys. Reassemble the belt guard and perform a functional test by engaging the drive and verifying smooth operation without slipping under load.

V belt and pulley alignment checks are essential for optimal drive performance and long belt life. Begin by ensuring both pulleys run concentric to each other and are aligned within the manufacturer’s specified tolerance, typically a few millimeters of lateral misalignment. Use alignment tools or a straight edge to verify that the belt sits evenly on both pulleys and that no edge is riding high or low. Inspect the belt path for proper tracking and absence of rubbing on the frame or guards. If misalignment is detected, loosen mounting hardware only enough to adjust the pulleys or belt tensioners, realign, and retorque to the specified values. After alignment, rotate the assembly by hand to confirm quiet operation with no rubbing or binding, then perform a controlled test under load to ensure consistent speed and power transfer without belt slippage or overheating.

The steering linkage on a Craftsman 917.273640 involves several interconnected components that ensure precise control and responsive handling. Start by inspecting the tie rods, idler arm, pitman arm, and linkage joints for excessive play, bending, or corrosion. Any looseness in the joints can translate into imprecise steering or wandering performance, so carefully check all fasteners for proper torque as specified by the manufacturer. When performing adjustments, ensure that all joints operate freely through their full range without binding, and replace any worn components to restore the system’s integrity. During inspection, also verify that the steering column collar and linkage mounting points are secure and free of damage, and check for signs of looseness at the steering box or rack if applicable. Maintaining clean, lubricated surfaces around the steering linkage helps reduce wear and prolongs the life of the components involved in steering input transmission.

Suspension components wear inspection and replacement require a systematic approach to identify fatigue or failure indicators. Examine the springs, shock absorbers, control arms, bushings, and mounting hardware for cracks, sagging, or leakage. Worn bushings or fatigued springs can result in poor ride quality, compromised stability, and uneven tire wear, so replace any components showing visible wear or degraded performance. When removing and replacing suspension parts, use manufacturer-recommended torque specifications and ensure proper alignment of mounting brackets to maintain correct geometry. Pay particular attention to ball joints and steering knuckles, which can exhibit play that affects handling. After replacement, perform a thorough test ride at varying speeds and road conditions to confirm that the suspension maintains consistent damping, rebound, and body control without unusual noises or harshness.

Wheel alignment and tire considerations are critical for both safety and optimal vehicle performance. Begin with a thorough inspection of tire condition, tread depth, and wear patterns, as irregular wear can indicate misalignment or worn suspension components. Use appropriate alignment specs for toe, camber, and caster, and verify that all adjusting bolts and shims are set to the manufacturer’s recommendations. When adjusting alignment, ensure the steering wheel is centered and that tires are inflated to the correct pressures to achieve accurate readings. Monitor for pulling to one side, uneven tire wear, or steering wheel offset, and address any underlying causes before finalizing alignment. Finally, select tires that match the vehicle’s load rating, vehicle weight distribution, and intended use to maintain stable handling characteristics and extend tire life under varied operating conditions.

Safety systems and diagnostics

The safety systems on modern lawn equipment integrate multiple interlocks, sensors, and control logic to prevent operation under unsafe conditions. Understanding these components helps technicians perform accurate diagnostics while maintaining proper safeguards. Each interlock is designed to verify that critical conditions, such as blade engagement, seat occupancy, and brake engagement, are met before allowing engine start or operation. A systematic approach to testing these interlocks ensures that no single fault falsely indicates safety compliance or, conversely, masks a dangerous condition. Always verify power down and proper isolation procedures before handling any safety-related hardware to prevent accidental engagement during maintenance.

Interlock checks involve verifying continuity and correct state across switches, relays, and wiring harnesses. Start with the most critical safety path, typically the brake/kill system and blade engagement circuit, then move to auxiliary interlocks like seat switches and operator presence controls. For accurate readings, use the manufacturer-recommended test procedures and reference the wiring schematic to identify expected fault codes and normal operating states. Document any deviations, including intermittent signals or corrosion on connectors, since poor connections can mimic failed components or create unpredictable behavior. When an interlock is found defective, replace it with an approved part and re-test the entire safety chain to confirm proper operation.

Diagnostic procedures using code readers involve connecting a compatible scanner that can interface with the mower’s engine control module or ECU. Begin by powering down the unit, connect the reader at the designated diagnostic port, and follow the on-screen prompts to retrieve stored trouble codes. Record the codes verbatim and cross-reference them with the service manual for the recommended corrective actions. Many engines store historical codes that indicate past faults not currently active; clearing codes should be done only after repairs are verified to ensure accurate future diagnostics. When a code indicates a safety interlock fault, perform a physical inspection of the corresponding switch, wiring, and connector before replacing components to confirm the fault is not a wiring problem or a temporary electrical interference.

Troubleshooting common error codes requires a structured approach to isolate whether the fault is mechanical, electrical, or related to software logic. Start with the most severe safety-related codes, as these typically prohibit starting or full operation. Validate that the battery voltage is within specification, as low voltage can trigger spurious fault indications. Inspect the harness grounds and battery terminals for cleanliness and tightness, since poor grounding can cause intermittent sensor readings. If the code points to a specific sensor or switch, test its resistance, continuity, and response time in known good conditions. Replace failed components with OEM parts, and recheck the system to confirm that the fault has been resolved and that the diagnostic trouble code no longer reappears during normal operation.

During maintenance, it is important to perform a comprehensive safety verification after any repair or adjustment. This includes a functional test of all interlocks, a no-load attempt to start the engine, and a controlled blade engagement test with appropriate protective equipment in a safe environment. Document all findings, parts replaced, and test results in the service log for future reference. Additionally, verify that service bulletins or firmware updates issued by the manufacturer have been applied if applicable, as these can alter diagnostic codes or safety logic behavior. Routine checks of wiring harness integrity, shielded cables, and connectors will help minimize false positives and ensure long-term reliability of the safety systems.

In summary, effective safety system maintenance combines rigorous interlock verification, methodical diagnostic code reading, and careful interpretation of fault codes in the context of the machine’s electrical and mechanical state. A disciplined workflow reduces incorrect repairs, enhances operator safety, and supports dependable machine performance. By following these practices, technicians can accurately diagnose and resolve safety system issues while maintaining compliance with the manufacturer’s specifications and recommended service procedures.

Safety is the foundation of reliable outdoor power equipment operation. When in doubt, consult the official service manual for your model and reach out to authorized support channels to confirm any ambiguities. The goal is to restore full, safe functionality and prevent future fault occurrences through precise testing, proper part replacement, and thorough documentation of all maintenance activities.

The maintenance schedule for the CRAFTSMAN 917.273640 is designed to keep the machine performing at peak efficiency and to extend its service life. Establish a routine that aligns with the operator’s usage level and local environmental conditions. For regular use, perform a basic inspection and service every 25 hours of operation or quarterly, whichever comes first. This baseline should include checking the air filter, spark plug condition, fuel system cleanliness, and lubrication points to prevent wear and ensure reliable starting. If the mower operates in dusty or sandy environments, increase the frequency to every 15–20 hours to maintain optimal performance and reduce the risk of component fouling. Adhere to a more conservative schedule if the machine experiences hard starting, misfiring, or unusual vibrations, and perform a comprehensive inspection to identify the underlying cause before it progresses to a more serious fault. Regularly consulting the service manual for torque specifications and part inspection criteria is essential to avoid over-tightening or missing critical adjustments during short maintenance sessions.

Record keeping and documentation are critical for tracking maintenance history and planning future service. Maintain a dedicated log that includes the date of service, hours of operation since last service, parts replaced, and a brief note on observed conditions or anomalies. Photograph or timestamp any worn components or damaged hoses before replacement to aid in historical reference and warranty validation. Use a standardized checklist at each maintenance interval to ensure consistency, reduce the chance of overlooking a task, and establish a clear trail for future technicians. Store service records with the equipment receipts and the unit’s identification data so that critical information remains accessible during resale or warranty evaluation. Regular documentation supports troubleshooting efforts by revealing trends such as gradual declines in performance or increasing fuel consumption over time.

Winterization and long-term storage require careful preparation to prevent corrosion, fuel degradation, and core component damage. Before storage, complete a full service as if preparing for operation, but extend inspection to seasonal reminders such as battery condition, blade balance, and belt wear. Drain or stabilize fuel according to local regulations and manufacturer recommendations to prevent varnish buildup and fuel system gumming during extended inactivity. Remove moisture from the cooling and ventilation paths by ensuring there is no debris buildup around the engine and cooling fan areas, and apply a light protective coat to metal surfaces to discourage corrosion. Store the unit in a dry, elevated location away from extreme temperatures and direct sunlight, with batteries disconnected or stored on a trickle charger if applicable. Upon return to use, re-check all fluid levels, fasteners, and safety switches to confirm the machine is ready for safe operation after storage.