Stihl FS 55 RC Manual: A Comprehensive Guide
This manual provides detailed instructions for the Stihl FS 55 RC string trimmer, covering operation, maintenance, troubleshooting, and safety—essential for optimal performance.
Recent discussions highlight potential issues with HP Ultra oil and carburetor problems, alongside insights into top-handle saw models like the Stihl 192T/193T.
The Stihl FS 55 RC is a popular, lightweight string trimmer designed for residential users and landscaping professionals alike. It’s renowned for its ease of use, reliable performance, and efficient cutting capabilities. This model features a loop handle for comfortable operation and is ideal for trimming grass, weeds, and small brush around yards and gardens.
Recent online discussions reveal user experiences with the FS 55 RC, including concerns about oil film sufficiency when using Stihl HP Ultra and troubleshooting fuel-related issues like excessive fuel expulsion from the exhaust. Understanding these potential challenges is crucial for maintaining optimal trimmer function.
This guide will equip you with the knowledge to safely operate, maintain, and repair your Stihl FS 55 RC, ensuring years of dependable service.
Understanding the FS 55 RC Model
The Stihl FS 55 RC boasts a 27.2 cc engine, delivering ample power for various trimming tasks. Its key features include easy start technology and a robust gearbox designed for durability. The RC designation signifies a round handle, providing enhanced control during operation. This model is compatible with a range of Stihl accessories, expanding its versatility.
User feedback highlights potential carburetor issues, such as running rich and flooding, particularly in older models. Additionally, discussions mention oil pump failures, despite proper function, requiring further investigation. Recognizing these common concerns aids in proactive maintenance.
Familiarizing yourself with these aspects will maximize the FS 55 RC’s performance and longevity.
Safety Precautions
Always wear appropriate PPE, including eye and hearing protection, gloves, and sturdy footwear. Handle fuel with care, avoiding spills and ensuring proper ventilation.
General Safety Warnings
Read and understand this manual thoroughly before operating the Stihl FS 55 RC. Improper use can lead to serious injury. Always disconnect the spark plug wire before performing any maintenance or adjustments. Never operate the trimmer with damaged parts, and ensure all guards are securely in place.
Be aware of your surroundings, keeping bystanders, especially children, at a safe distance. Avoid operating in wet or slippery conditions. Never modify the trimmer in any way, as this could compromise safety features. Always shut off the engine before setting it down.
Personal Protective Equipment (PPE)
Always wear appropriate Personal Protective Equipment (PPE) when operating the Stihl FS 55 RC. This includes safety glasses or a face shield to protect your eyes from flying debris. Wear hearing protection, such as earmuffs, to prevent noise-induced hearing loss. Sturdy, long-sleeved clothing and long pants are essential for skin protection.
Wear durable gloves to improve grip and protect your hands. Always wear appropriate footwear, such as steel-toed boots, to protect your feet. A dust mask is recommended when working in dusty conditions.
Safe Handling of Fuel
Fuel handling requires extreme caution. Always mix fuel in a well-ventilated area, away from sparks, open flames, or heat sources. Use a Stihl-approved fuel container and adhere to the correct fuel-to-oil ratio as specified in this manual. Never smoke while handling fuel.
Avoid spilling fuel and immediately wipe up any spills with a clean cloth. Store fuel in a cool, dry place, out of reach of children. Be aware of potential carburetor issues that can lead to fuel leaks.
Component Identification
Familiarize yourself with the FS 55 RC’s key parts: engine, cutting head, handle, and controls. Understanding these components is crucial for assembly and maintenance procedures.
Engine Components
The Stihl FS 55 RC engine features a robust 2-stroke design, requiring a precise fuel-oil mixture for optimal lubrication and performance. Key components include the cylinder, piston, crankshaft, and connecting rod, all working in harmony to generate power.
Essential systems include the carburetor, responsible for fuel delivery, and the ignition system, initiating combustion. The spark plug, air filter, and muffler are also vital for efficient engine operation. Valve adjustments, though less frequent, are crucial for maintaining compression and power output.
Cutting Head and Attachments
The Stihl FS 55 RC utilizes a versatile cutting head, accepting various attachments for different trimming tasks. Standard options include nylon trimmer line for grass and weeds, and optional blade attachments for thicker vegetation.
Proper attachment installation is crucial for safe operation, ensuring secure locking mechanisms are engaged. Regular inspection of the cutting line or blades is essential, replacing worn or damaged components promptly. Maintaining the cutting head prevents debris ejection and ensures efficient trimming performance.
Handle and Controls
The Stihl FS 55 RC features ergonomically designed handles for comfortable and controlled operation. Key controls include the throttle trigger, which regulates engine speed, and the on/off switch, controlling engine operation. A stop switch immediately halts the engine in emergencies.
Familiarize yourself with the location and function of each control before use. The throttle lockout prevents accidental throttle engagement, enhancing safety. Proper grip and control are vital for precise trimming and minimizing operator fatigue during extended use.
Assembly and Initial Setup
Proper assembly is crucial for safe operation. This involves attaching the cutting head, carefully mixing fuel, and adjusting the harness for a secure and comfortable fit.
Attaching the Cutting Head
Securely attaching the cutting head is paramount for effective trimming and operator safety. Begin by ensuring the engine is switched off and the spark plug is disconnected. Align the cutting head with the drive shaft, carefully inserting it until it clicks firmly into place.
Verify the locking mechanism engages correctly, preventing accidental detachment during operation. Rotate the head manually to confirm free movement. Incorrect attachment can lead to damage or injury, so double-check before proceeding. Always refer to the diagram in the manual for correct orientation.
Fuel Mixing and Filling
Proper fuel mixing is crucial for the longevity of your Stihl FS 55 RC engine. Utilize a high-quality 2-cycle engine oil, like Stihl HP Ultra, and adhere strictly to the recommended fuel-to-oil ratio specified in the manual – typically 50:1.
Thoroughly mix the fuel and oil in a clean container before pouring it into the fuel tank. Avoid spilling fuel on the engine or surrounding areas. Always use fresh fuel and store it properly in an approved container, away from heat sources.
Adjusting the Harness
Correct harness adjustment is vital for operator comfort and reduced fatigue during extended use of the Stihl FS 55 RC. Begin by loosening all straps, then position the harness comfortably on your shoulders.
Tighten the shoulder straps to distribute the weight evenly, ensuring the trimmer doesn’t bounce excessively. Adjust the waist belt for a secure fit, preventing the unit from shifting during operation. Regularly check and readjust straps as needed for optimal support.
Operation Instructions
Proper operation of the Stihl FS 55 RC involves safe starting, effective trimming techniques, and a secure engine shutdown procedure for longevity.
Starting the Engine
Before starting, ensure the cutting head is clear of obstructions and the trimmer is on a stable surface. Engage the choke by moving the choke lever to the ‘start’ position, then prime the fuel bulb several times until fuel is visible.
Firmly grasp the starter handle and pull the cord with a quick, decisive motion. Repeat this several times, gradually reducing choke application as the engine attempts to start. Once running, slowly disengage the choke.
If the engine floods, remove the spark plug, pull the starter cord to clear the cylinder, and repeat the starting procedure. A weak pull suggests potential carburetor or valve issues.
Trimming Techniques
Maintain a safe distance from obstacles like trees, fences, and structures while trimming. Use a sweeping motion, moving the trimmer head from side to side, allowing the line to cut the grass and weeds effectively.
Avoid forcing the trimmer line into thick vegetation, as this can cause premature wear and breakage. For stubborn growth, reduce speed and make multiple passes;
Angle the trimmer head slightly to prevent scalping the ground. Regularly inspect the cutting line for wear and replace as needed to maintain optimal trimming performance.
Stopping the Engine
To stop the engine, release the throttle trigger and press the on/off switch to the “0” or “STOP” position. Ensure the trimmer head is clear of any obstructions before shutting down.
Allow the engine to come to a complete stop before setting the trimmer down or storing it. Never rely solely on the throttle to stop the engine, as this can lead to idling and potential hazards.
Inspect the trimmer for any damage or fuel leaks after stopping. Proper shutdown procedures contribute to the longevity and safe operation of your Stihl FS 55 RC.
Maintenance and Care
Regular maintenance ensures optimal performance and extends the life of your Stihl FS 55 RC. Key tasks include filter cleaning, spark plug checks, and lubrication.
Air Filter Cleaning
Maintaining a clean air filter is crucial for engine performance. A dirty filter restricts airflow, leading to reduced power and increased fuel consumption. Regularly inspect the air filter—more frequently in dusty conditions.
To clean, gently tap the filter to remove loose debris. For stubborn dirt, wash the filter in warm, soapy water, then rinse thoroughly and allow it to dry completely before reinstalling. Never operate the trimmer with a wet or damaged air filter. Replacement is recommended if cleaning doesn’t restore airflow.
Spark Plug Inspection and Replacement
Regular spark plug inspection ensures reliable engine starting and efficient combustion. Examine the plug for fouling, wear, or damage. A properly functioning spark plug exhibits a light tan or gray color. Black, oily deposits indicate a rich fuel mixture, while white deposits suggest a lean condition.
To replace, use the correct spark plug specified for your FS 55 RC model. Gap the new plug to the manufacturer’s specifications before installation. Ensure the plug is tightened securely, but avoid over-tightening to prevent damage to the cylinder head.
Fuel Filter Replacement
A clean fuel filter is crucial for consistent engine performance and prevents debris from entering the carburetor. Replace the fuel filter periodically, especially if you notice reduced engine power or difficulty starting. Symptoms like raw fuel expulsion from the exhaust can indicate a clogged filter.
Locate the fuel filter within the fuel tank, carefully remove it, and install a new, genuine Stihl replacement. Ensure proper fuel line connections to avoid leaks. Regularly checking and replacing the filter maintains optimal fuel delivery.
Gearbox Lubrication
Proper gearbox lubrication is vital for the longevity and smooth operation of your Stihl FS 55 RC. The gearbox houses critical components subject to high stress and friction. Regularly inspect the gearbox for leaks and ensure it’s filled with the recommended Stihl gear oil.
Follow the manufacturer’s guidelines for lubrication intervals, typically after every 50 hours of use or annually. Use only Stihl-approved lubricants to prevent damage and maintain warranty validity. This simple maintenance step significantly extends the life of your trimmer.
Cutting Head Maintenance
Consistent cutting head maintenance ensures efficient and safe operation of your Stihl FS 55 RC. Regularly inspect the trimmer head for worn or damaged parts, including the line, spool, and eyelets. Replace trimmer line as needed, using the recommended diameter specified in the manual.
Clean the cutting head thoroughly after each use, removing grass clippings and debris. Periodically disassemble and inspect the spool and spring for proper function. Addressing minor issues promptly prevents more significant repairs and maintains optimal cutting performance.
Troubleshooting Common Issues
This section details solutions for typical FS 55 RC problems, such as starting difficulties, poor engine performance, oil pump failures, and potential fuel leaks.
Engine Won’t Start
If the engine fails to start, first verify the fuel tank contains a proper fuel mixture. Ensure the choke is engaged correctly, especially when cold starting. Check the spark plug for fouling or damage, replacing if necessary.
Confirm the spark plug wire is securely connected. A weak pull rope sensation, as reported with some 4-mix engines, could indicate internal issues needing professional attention. Inspect the air filter for obstructions.
Raw fuel expulsion from the exhaust suggests carburetor problems, potentially requiring cleaning or rebuilding. Remember, a faulty carburetor can prevent ignition, even with a good spark.
Engine Runs Poorly
If the engine runs erratically or lacks power, suspect fuel delivery issues. A clogged fuel filter or incorrect fuel mixture are common culprits. Inspect the carburetor for debris or a rich fuel condition, as seen in older models like the Stihl 009.
Ensure the spark plug is clean and properly gapped. A weak oil pump, even while pumping, might not adequately lubricate the engine, leading to performance decline.
Consider potential problems with Stihl HP Ultra oil, as some users report insufficient film in the crankcase, potentially causing engine damage over time.
Oil Pump Problems
Insufficient bar and chain lubrication can quickly damage the cutting head. If the oil pump is running but no oil reaches the bar, check for a blocked oil line or a faulty oiler. Ensure the oil tank isn’t obstructed and the oil is flowing freely.
A user reported a new saw with a functioning pump delivering no oil, suggesting internal pump issues. Verify the pump’s intake screen isn’t clogged.
Consider the oil type; while Stihl HP Ultra is recommended, some users have voiced concerns about adequate film build-up.
Fuel Leaks
Fuel leaks pose a significant fire hazard and require immediate attention. Inspect the fuel lines, fuel tank, and carburetor for cracks or loose connections. A common issue reported involves excessive fuel expulsion from the exhaust, indicating carburetor problems.
Ensure the fuel cap is securely tightened. Check the carburetor for proper sealing and replace any worn gaskets.
If leaks persist after inspection, discontinue use and consult a qualified Stihl service technician. Improper fuel handling can lead to engine damage and safety risks.
Technical Specifications
The Stihl FS 55 RC boasts a 27.2 cc engine displacement and delivers 1.5 horsepower. It features a 0.8-liter fuel capacity, weighing approximately 11.2 pounds.
Engine Displacement and Power
The Stihl FS 55 RC is equipped with a robust 27.2 cubic centimeter (cc) engine, providing ample power for various trimming tasks. This engine delivers a power output of 1.5 horsepower (hp), offering a balance between performance and fuel efficiency.
This configuration makes the FS 55 RC suitable for homeowners and professionals alike, capable of handling grass, weeds, and light brush effectively. The engine’s design prioritizes reliability and longevity, ensuring consistent operation.
Fuel Capacity
The Stihl FS 55 RC boasts a fuel tank capacity of 0.5 liters (approximately 17 fluid ounces). This allows for extended operation without frequent refueling interruptions, maximizing productivity during trimming tasks.
It’s crucial to utilize a properly mixed fuel blend of gasoline and high-quality 2-cycle engine oil, specifically Stihl HP Ultra or an equivalent. Maintaining the correct fuel ratio is vital for optimal engine performance and longevity, preventing damage.
Weight and Dimensions
The Stihl FS 55 RC is designed for user comfort and maneuverability, weighing in at approximately 5;5 kilograms (12.1 pounds) without the cutting attachment. Its compact dimensions contribute to ease of handling in various trimming scenarios.
Overall length is around 1.77 meters (5.8 feet) with the standard straight shaft, while the width and height vary slightly depending on the installed cutting head. These specifications make it suitable for both residential and professional use.
Stihl HP Ultra Oil Considerations
Stihl HP Ultra is a 2-cycle oil formulated for optimal performance, but recent reports suggest potential issues with insufficient oil film in the crankcase—requiring careful monitoring.
Understanding 2-Cycle Oil
Two-cycle engines, like those in the Stihl FS 55 RC, require a precise fuel-oil mixture for lubrication. Unlike four-stroke engines with separate oil reservoirs, 2-cycle oils are blended directly with gasoline.
This mixture lubricates vital components like the piston, cylinder, and crankshaft. Using the correct oil ratio is crucial; too little oil leads to excessive wear, while too much causes carbon buildup and reduced performance.
Stihl HP Ultra is specifically designed for their engines, but monitoring oil film and potential issues, as discussed by experienced users, is always recommended for longevity.
Potential Issues with HP Ultra
While Stihl HP Ultra is formulated for optimal performance, some users have reported concerns regarding adequate oil film within the crankcase. This potential deficiency, noted by experienced chainsaw mechanics, could lead to increased wear on internal engine components over time.
Monitoring oil levels and observing engine behavior is crucial. Reports of premature engine failure with minimal hours suggest diligent observation is necessary when utilizing HP Ultra.
Consider alternative high-quality 2-cycle oils if concerns persist, ensuring compatibility with the Stihl FS 55 RC’s engine specifications.
Carburetor Issues and Repair
A faulty carburetor can cause running problems, like fuel expulsion from the exhaust. Cleaning procedures are vital; replacement alone may not resolve the issue.
Symptoms of a Faulty Carburetor
Identifying a carburetor issue is crucial for maintaining your Stihl FS 55 RC. Common signs include difficulty starting the engine, even with a new spark plug, and a noticeable loss of power during operation.
Excessive fuel being blown out of the exhaust pipe is a strong indicator, as is the engine running briefly with the choke fully engaged.
Consistent flooding or an inability to reach proper engine speed also points towards carburetor malfunction. These symptoms suggest a blockage or improper fuel mixture, requiring attention.
Carburetor Cleaning Procedures
To clean the carburetor, carefully disassemble it, noting the position of all parts. Use carburetor cleaner to thoroughly flush all passages, paying close attention to the jets and fuel intake screens.
Compressed air can help dislodge stubborn debris, ensuring clear fuel flow. Inspect the carburetor’s diaphragm for cracks or damage, replacing it if necessary.
Reassemble the carburetor meticulously, ensuring all components are correctly positioned before reinstalling it on the engine. Proper cleaning restores optimal fuel delivery.
Valve Adjustment
Proper valve clearance is crucial for engine performance. Checking and adjusting valve settings ensures efficient combustion and prevents issues like weak running or hard starting.
Checking Valve Clearance
To check valve clearance, the engine must be cold. Remove the spark plug and rotate the engine until both valves are closed – this is typically when the piston is at top dead center.
Use a feeler gauge to measure the clearance between the valve stem and the rocker arm. Consult the Stihl FS 55 RC manual for the specified clearance values. Incorrect clearance can lead to poor performance or engine damage. A volunteer trail crew experienced issues where valve adjustment didn’t resolve a running problem.
Record the measurements for both intake and exhaust valves before proceeding to adjustment if needed.
Adjusting Valve Settings
Adjusting valve settings requires specific tools and careful attention to detail. Loosen the rocker arm locknut and use the adjusting screw to achieve the correct valve clearance, as specified in the Stihl FS 55 RC manual.
Re-check the clearance with a feeler gauge after each adjustment. Tighten the locknut securely once the correct clearance is set. A trail crew found valve adjustment alone insufficient for resolving a running issue, highlighting the need for comprehensive diagnostics.
Repeat the process for both intake and exhaust valves.
Top Handle Saw Considerations (Related Stihl Models)
Stihl’s 192T/193T series are popular top-handle saws, offering a compact design for professional arborists—useful knowledge for Stihl power tool owners.
Overview of Stihl 192T/193T Series
The Stihl 192T and its successor, the 193T, are renowned top-handle saws favored by arborists for their maneuverability in trees. These saws feature a compact design and relatively lightweight construction, making them ideal for pruning and limbing.
The 193T boasts an improved engine and increased power compared to the 192T, offering enhanced performance for demanding tasks. Both models require specialized training and adherence to strict safety protocols due to their unique handling characteristics.
Experienced users often discuss rebuilding and modifications to optimize these saws for specific applications, highlighting the importance of proper maintenance and understanding their intricate mechanics.
Rebuilding and Modifications
Experienced Stihl 192T/193T users frequently undertake rebuilds to restore performance and extend the lifespan of these top-handle saws. Common modifications include porting the cylinder for increased power and upgrading the carburetor for improved fuel delivery.
Careful attention to detail is crucial during disassembly and reassembly, ensuring proper component alignment and torque specifications. Discussions often center around optimizing oiling systems and addressing potential weaknesses in the engine case.
These modifications require a thorough understanding of engine mechanics and should only be performed by qualified individuals to maintain safety and reliability.