STIHL 028 Service Manual
Overview and safety considerations
Safety must be the first consideration whenever operating a chainsaw, and the STIHL 028 is no exception. Before any starting procedure or cutting task, perform a thorough inspection of the saw, including the bar and chain tension, chain lubrication, spark plug condition, fuel and oil levels, and air filter integrity. Always ensure the chain is sharp and properly tensioned, as a dull or loose chain increases kickback risk and reduces control. Clear the work area of obstacles, bystanders, and trip hazards, and establish an escape route in case of chain bind or sudden engine stall. Verify that the starting and stop mechanisms function smoothly, and check that the chain brake engages fully when activated. A well-prepared operator reduces the likelihood of injuries and mechanical damage, and sets the stage for an efficient cutting session.
Personal protective equipment (PPE) is essential for reducing injury during operation. Wear a certified cut-resistant chaps or trousers, a safety helmet with face shield, hearing protection, and sturdy gloves. Use non-slip, steel-toed boots with good ankle support to maintain stability on uneven terrain. Eye protection should be worn at all times to shield against flying sap, wood particles, and debris that can be propelled by the chain. In addition, keep a first-aid kit and a mobile communication device readily accessible in case of emergencies. PPE not only guards against physical injury but also helps minimize fatigue by improving grip and comfort during extended cutting tasks.
The STIHL 028 model is a mid-range chainsaw with specific maintenance and operating considerations. Familiarize yourself with the user manual and diagnostic procedures that pertain to this model, including fuel mixture ratios, spark plug type, carburetor adjustments, and cooling fins cleaning. Always use the recommended fuel-oil ratio and avoid old or contaminated fuel, which can cause poor starting, reduced power, and increased emissions. Proper warm-up intervals allow the engine to reach optimal operating temperature, promoting smoother idle and reducing wear on internal components. When transporting or storing the saw, follow proper shutdown procedures to prevent accidental startups and preserve fuel system integrity. A clear understanding of the model’s features helps you perform safer operation and easier future maintenance.
The STIHL 028 chainsaw requires periodic replacement of worn components to maintain safe and efficient operation. Recommended replacement parts and wear items include air filters, fuel filters, spark plugs, and seals that show signs of degradation, as well as standard wear items like drive sprockets, bar and chain components, and across-the-board gaskets. Prioritize OEM STIHL parts to ensure compatibility with ignition timing, fuel mixture, and lubrication flow. Maintain a replacement schedule based on operating hours, load conditions, and environmental exposure, and keep a log to track part life, service dates, and observed performance changes. Regular inspection of these components helps prevent sudden failures and prolongs overall equipment life.
Incorporate routine lubrication checks for the chainsaw’s moving parts, ensuring that the bar groove and spark plug are properly serviced. Use the manufacturer-recommended lubricants and oils to maintain optimal chain speed, reduced wear, and consistent power delivery. Monitor the chain oil reservoir and adjust flow if you notice inadequate lubrication or excessive chain heating during operation. Cleanliness is essential; remove debris from the air intake and muffler area to prevent restricted airflow, which can lead to overheating and accelerated wear on fuel and lubrication pathways. A well-lubricated system minimizes friction, enhances cutting efficiency, and extends the life of critical engine and bar components.
Air filter and carburetor basics involve choosing the correct filter type and ensuring a clean, unobstructed air intake pathway. Inspect the air filter for rips, tears, or collapsed media and replace it promptly to maintain proper fuel-air mixture and engine performance. When servicing the carburetor, verify idle speed, fuel metering, and choke operation, ensuring smooth transitions between starting and running conditions. Use clean, high-quality fuel and two-stroke oil in the proper ratios, and replace the fuel filter during scheduled maintenance or if fuel filtration is compromised. Regular carburetor adjustment and air pathway cleaning help prevent rough idling, misfires, and power loss, which are indicative of improper air-fuel balance and potential dirt intrusion.
Diagnostics and troubleshooting
Normal start up and running indicators are essential for confirming that your STIHL 028 chainsaw is operating within specifications. When starting the engine, listen for a consistent ignition sequence, a smooth idle, and steady throttle response without sputtering or stalling. Observe exhaust color; a healthy engine typically produces light, nearly invisible smoke, whereas dark, roaring plumes may indicate rich fuel mix or improper carburetor adjustment. Temperature behavior is also telling: the engine should reach operating temperature promptly without overheating, and cooling fins should remain free of obstructions. If any of these indicators deviate from the norm, perform a controlled diagnostic check starting with fuel quality, air filter condition, and spark plug integrity before advancing to more advanced tests. Regularly recording start-up times and run characteristics can help you detect gradual degradation before it affects performance.
Common symptoms and corrective actions require a structured approach to identify root causes without excessive disassembly. If the saw fails to start, verify fuel mixture ratio, fuel line condition, and the presence of a proper spark at the spark plug. A no-spark condition often points to faulty ignition coil, worn spark plug, or dead kill switch wiring, while a flooded carburetor manifests as a stubborn start or heavy cranking with no ignition. If the engine turns over but runs poorly, inspect the air filter for clogging, perform a carburetor adjustment within the manufacturer’s specifications, and ensure the muffler isn’t restricted by carbon buildup. For running issues such as misfiring or sudden power loss, evaluate the spark plug gap, inspect for flywheel magnet damage, and check for vacuum leaks around the carburetor and intake manifold. Document any recurrent patterns to guide precise maintenance steps and avoid unnecessary disassembly.
Tool and accessory compatibility checks are critical to ensure safe and efficient operation of the STIHL 028. Always verify that the correct bar length and chain gauge are installed for your model and that the chain is sharply tensioned according to the manual. Confirm that the spark plug type, gap, and reach match the specifications for your engine variant, replacing worn or fouled plugs with OEM parts. Carburetor adjustments should be performed with the proper diagnostic tools, and only after confirming fuel delivery and air intake are unobstructed. When using a new accessory, such as a bar or chain, inspect mounting hardware for tightness and wear, and re-check alignment and lubrication points after initial run to ensure consistent performance. Maintaining the correct tool and accessory combination not only enhances safety but also prolongs engine life and reduces troubleshooting time in future maintenance sessions.
Disassembly and inspection procedures
Pre disassembly safety steps are essential to protect both the technician and the machine. Begin by disconnecting the spark plug wire and ensuring the engine is cool before any work starts. Verify fuel is drained or safely contained to prevent spills, and transport the saw on a stable work surface away from ignition sources. Gather the proper hand tools and keep a labeled parts tray to avoid misplacement of small components. Wear appropriate personal protective equipment, including gloves and eye protection, to guard against sharp edges and residual pressure in the cooling and fuel systems. Document the initial condition with clear notes or photos to aid in reassembly and to track wear patterns over time.
Removing components in a safe sequence requires a methodical approach to minimize damage and preserve alignment. Start with exterior covers or housings that secure the internal components, using the correct screwdrivers and torx bits to avoid stripped fasteners. Maintain a logical order so that removing one part does not force the removal of multiple assemblies unnecessarily. As you detach each component, note its orientation and any gasket or seal placements, replacing them only if specified by the manufacturer. When feasible, separate assemblies such as the clutch, sprockets, and bar/chain system in a way that allows for inspection of interconnected parts without disturbing calibrated settings. Take care to support heavier components during removal to prevent bending or twisting of shafts and linkages, which can compromise later operation and safety.
Inspection criteria for critical parts focus on identifying wear, corrosion, and fatigue that could affect performance. Inspect the crankshaft and bearings for lateral play, scoring, or evidence of overheating, and check the piston and rings for ring land movement or base surface wear. Examine the cylinder for scoring, carbon buildup, and glazing that might impair compression. Assess the ignition system for coil crackle or improper timing by testing spark quality and continuity, replacing worn ignition components as needed. Review the carburetor and fuel delivery passages for varnish deposits or restricted jets, ensuring seals and diaphragms remain pliable and free of cracks. Finally, evaluate the muffler and exhaust path for obstructions or significant corrosion, and ensure all fasteners meet the specified torque values to maintain structural integrity during operation.
The STIHL 028 requires precise carburetor adjustment to ensure optimal engine performance, fuel efficiency, and safe operation. Begin by disconnecting the spark plug boot and removing the fuel cap to relieve fuel pressure, then access the carburetor adjustment screws. Use the specified factory baseline settings as a starting point, and perform adjustments with the engine warm and at a stable idle. When tuning, ensure the air filter is clean and properly seated, as a restricted intake can skew idle and high-speed mixtures. After each adjustment, re-check the tachometer reading and perform a brief acceleration test to confirm smooth transition from idle to full throttle without hesitation or bogging. Document all settings once the engine runs cleanly across the RPM range for future reference and maintenance intervals.
Idle speed and chain brake checks are critical for safe operation and chain control. With the saw idling, verify that the chain brake engages fully and arrests the chain's motion within the manufacturer’s specified distance and time. If the chain remains partially engaged or the brake drags, inspect the brake band, return spring, and spring pin for wear or deformation, replacing as necessary. Adjust the idle speed so the chain remains stationary while maintaining enough idle torque to avoid stalling under light loads or when the cutting gear is engaged. Recheck the throttle trigger response after each adjustment to ensure immediate return to idle without sticking, and verify that the chain brake releases smoothly during throttle application. Safety rechecks should be performed with the bar and chain removed from the workpiece to confirm consistent brake and clutch operation.
Fuel system tuning considerations for the STIHL 028 involve ensuring reliable fuel delivery, proper nozzle flow, and absence of air leaks. Inspect the fuel line for cracks, hard spots, or loose clamps and replace damaged segments to prevent air ingress. When adjusting the carburetor, confirm that the low and high-speed screws mate to the recommended turns and that the high-speed jet provides sufficient fuel at full throttle without flooding or hesitation. Consider the impact of fuel quality and ethanol content on carburetor components, and use fresh, suitable fuel with a compatible fuel stabilizer if the saw will be stored for extended periods. If the engine exhibits starting difficulties or inconsistent running after a routine service, perform a careful leak-down or vacuum test of the intake and carb connections, as even minor leaks can cause lean running, misfires, or idle instability and will require reseating gaskets and fittings. Maintain clean, dry handling during disassembly and reassembly to avoid contaminating the fuel passages and to preserve the integrity of the diaphragm and needle valve assemblies.
The reassembly process for the STIHL 028 follows the teardown order in reverse, ensuring that components are installed in the proper sequence to restore function and maintain reliability. Begin by inspecting all parts for wear, damage, or deformation and replace any suspect items prior to reassembly. Clean mating surfaces thoroughly to remove debris, old gasket material, and residual lubricants that could impair seals or alignment. When reinstalling components, apply appropriate lubricants, gaskets, and seals as specified by STIHL tolerances to maintain proper compression and sealing. Take care to orient all parts correctly, paying close attention to timing marks, splines, and keyways to avoid misalignment that could compromise engine timing or operation.
Carefully reinsert the crankcase components in the precise order used during teardown, ensuring that fasteners engage with the correct threads and seat to the required depth. Use the specified torque values for each fastener and verify that fasteners are tightened in the correct sequence to promote even clamping pressure and prevent warping or gasket failure. After tightening, recheck clearances and bearing fits where applicable, and rotate the crank by hand to confirm smooth operation without binding. Preserve the integrity of gaskets and seals by not over-tightening fasteners, and replace any gaskets that show signs of damaged edges or compression.
With the major assemblies in place, perform a thorough functional test and safety verification to ensure the rebuild meets its performance and reliability goals. Ensure the ignition system functions properly, including spark delivery and coil grounding, and verify that the air-fuel delivery system is free of leaks and operates within specification. Test the recoil starter or electric start mechanism for smooth engagement and full stroke to confirm reliable starting performance. Finally, perform a cautious run test at no-load and gradual load applications, listening for unusual noises, checking exhaust emissions, and confirming that safety systems such as chain brake or stop switch respond correctly to operator input.
Preventive maintenance and long term care for the STIHL 028 requires a disciplined schedule to preserve compression, reliability, and safety. Establishing a routine that includes regular inspection of bearings, fuels, air filtration, and ignition components will extend engine life and reduce unexpected downtime. Begin with a visual check for any oil leaks, fuel line wear, or loose fasteners, and address these issues before operation to prevent component damage. Document any irregularities and corrective actions to build a maintenance history that informs future service decisions. A proactive approach to maintenance reduces the likelihood of catastrophic failures and helps maintain optimal performance across long-term usage.
Scheduled service intervals provide a practical framework for orderly care. Create a maintenance calendar that aligns with hours of operation or months of inactivity, and mark tasks such as air filter replacement, spark plug inspection, fuel system cleaning, and carburetor adjustment at defined points. Regularly replace or clean air filters to ensure unobstructed airflow, which directly influences engine efficiency and emissions. Inspect the cooling system, including cooling fins and shrouds, to prevent overheating during demanding cutting tasks. Maintaining a consistent service rhythm minimizes peak load on parts and supports smoother operation over years of service life.
Storage and anti-corrosion tips are essential for preserving engine components between uses. When storing for extended periods, drain the fuel or add a stabilizer to reduce varnish buildup in the carburetor and fuel lines. Clean the exterior surfaces to remove sap, dirt, and moisture that can promote corrosion, then apply a light coat of oil to metal touches to deter rust. Store the equipment in a dry, ventilated area away from direct sunlight and extreme temperatures, and keep it on a stand or pad to protect the cooling surfaces and underside. Periodically rotate the starting system to prevent seized components, and check the fuel system again before the next operation cycle to ensure reliable starting and steady performance.
Record keeping and service logs are an integral part of sustained performance. Maintain a detailed log that captures date, hours of operation, parts replaced, tests performed, and any adjustments made. Use the log to track trends such as diminishing compression, unusual noises, or reduced cutting efficiency, which can signal the need for preemptive repairs. Include receipts and warranty information for any parts replaced, and note serial numbers for reference during future service. A well-maintained log not only supports compliance with safety and maintenance standards but also helps guide budgeting and procurement for ongoing upkeep of the STIHL 028.