Operator’s Manual CS-4910 Chainsaw The engine exhaust from this product contains chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm. Read and understand all provided literature before use. Failure to do so could result in serious injury. Note: This product complies with CAN ICES-2/NMB-2.
TABLE OF CONTENTS CS-4910 TABLE OF CONTENTS Introduction................................................................................................................. 3 Servicing Information.................................................................................................. 3 Parts and Serial Number.................................................................................... 3 Service ..................................................................................................
CS-4910 INTRODUCTION INTRODUCTION Specifications, descriptions, and illustrative material in this literature are as accurate as possible. Specifications are subject to change without notice. Illustrations might include optional equipment and accessories, and might not include all standard equipment. Your equipment might appear slightly different than pictured equipment. Read and understand all provided literature.
SERVICING INFORMATION CS-4910 Service Service of this product during the warranty period must be performed by an Authorized ECHO Service Dealer. For the name and address of the Authorized ECHO Service Dealer nearest you, ask your retailer or call: 1-800-432-ECHO (3246). Dealer information is also available on our Web Site www.echo-usa.com. When presenting your unit for Warranty service/ repairs, proof of purchase is required.
CS-4910 SAFETY SAFETY Manual Safety Symbols and Important Information Throughout this manual and on the product itself, you will find safety alerts and helpful, informational messages preceded by symbols or key words. The following is an explanation of those symbols and key words and what they mean to you. The safety alert symbol accompanied by the word “DANGER” calls attention to an act or condition which WILL lead to serious personal injury or death if not avoided.
SAFETY CS-4910 International Symbols Symbol Description WARNING! Read and follow all safety precautions in the instruction manual. Failure to follow instructions could result in serious personal injury. Wear Eye, Ear, and Head Protection. Tip contact may cause the guide bar to move suddenly upward and backward, which may cause serious injury.
CS-4910 Symbol SAFETY Description Symbol Chain Brake Operation Description Chain Oiler Adjustment Choke Control “COLD START” Position (Choke Closed) Purge Bulb Choke Control “RUN” Position (Choke Open) STOP Decompression Device STOP STOP / Momentary STOP Switch Note: Not all symbols will appear on your unit.
SAFETY CS-4910 Personal Condition and Safety Equipment Cancer and Reproductive Harm www.P65Warnings.ca.gov The muffler or catalytic muffler and surrounding cover may become extremely hot. Always keep clear of exhaust and muffler area, otherwise serious personal injury might occur. Users of this product risk injury to themselves and others if the unit is used improperly and/or safety precautions are not followed. Proper clothing and safety gear must be worn when operating unit.
CS-4910 SAFETY Hand Protection Wear sturdy, no-slip, rubber work gloves to improve your grip on the handles. Gloves also provide protection against cuts and scratches, cold environments, and reduce the transmission of machine vibration to your hands. Hearing and Ear Protection ECHO recommends wearing personal protective equipment whenever unit is used.
SAFETY CS-4910 The components of this machine generate an electromagnetic field during operation, which can interfere with some pacemakers. To reduce the risk of serious or fatal injury, persons with pacemakers should consult with their physician and the pacemaker manufacturer before operating this machine. In the absence of such information, ECHO does not recommend the use of this machine by anyone who has a pacemaker.
CS-4910 SAFETY Repetitive Stress Injuries (RSI) It is believed that overusing the muscles and tendons of the fingers, hands, arms, and shoulders may cause soreness, swelling, numbness, weakness, and extreme pain in those areas. Certain repetitive hand activities may put you at a high risk for developing a Repetitive Stress Injury (RSI). An extreme RSI condition is Carpal Tunnel Syndrome (CTS), which could occur when your wrist swells and squeezes a vital nerve that runs through the area.
SAFETY CS-4910 Rules for Safe Operation Kickback Safety Precautions for Chainsaw Users KICKBACK may occur when the nose or tip of the guide bar touches an object, or when the wood closes in and pinches the saw chain in the cut. Tip contact in some cases may cause a lightning fast reverse REACTION, kicking the guide bar up and back towards the operator. Pinching the saw chain along the top of the guide bar may push the guide bar rapidly back towards the operator.
CS-4910 SAFETY 2. Keep a good firm grip on the saw with both hands, the right hand on the rear handle, and the left hand on the front handle, when the engine is running. Use a firm grip with thumbs and fingers encircling the chainsaw handles. A firm grip will help you reduce kickback and maintain control of the saw. Don’t let go. 3. Make sure that the area in which you are cutting is free from obstructions.
SAFETY CS-4910 Testing the Brake • Start the engine on a solid level surface and run at a fast idle until warm. • Hold the saw firmly by the handles and accelerate the engine to a fast idle. • Slowly operate the chain brake lever while holding the saw firmly on the ground. When the brake lever trips, the chain should stop. Immediately release the throttle trigger. Do not allow the saw to tip forward in order to avoid damage to the chain.
CS-4910 ANSI Standard B175.1 and CSA Z62.1.3 stipulate that the brake shall stop the chain 0.12 seconds at an engine speed of 13,500 RPM. It is the responsibility of the owner/ operator to ensure that the brake is serviced, adjusted and tested strictly in accordance with the instructions as detailed here in order to ensure that the brake performance is maintained in compliance with the Standards B175.1 and CSA Z62.1.3. SAFETY 35 cm (14 in.
SAFETY CS-4910 Other Safety Precautions 1. Do not operate a chainsaw with one hand! Serious injury to the operator, helpers, bystanders, or any combination of these persons may result from one-handed operation. A chainsaw is intended for twohanded use. 2. Do not operate a chainsaw when you are fatigued. 3. Use safety footwear, snug-fitting clothing and protective gloves. Wear eye, hearing, and head protection devices. 4. Use caution when handling fuel. Move the chainsaw at least 3 m. (10 ft.
CS-4910 SAFETY 18. When transporting your chainsaw, use the appropriate guide bar scabbard. 19. A spark arrestor muffler approved to SAE Standard J335 is standard on this chainsaw to reduce the possibility of forest fires. Do not operate the chainsaw with a loose or defective muffler. Do not remove the spark arrester screen. 20. When using a chainsaw a fire extinguisher should be available. 21. When felling, keep at least two tree lengths between yourself and your fellow workers. 22.
SAFETY CS-4910 Moving parts can amputate fingers or cause severe injuries. Keep hands, clothing and loose objects away from all openings. ALWAYS stop engine, disconnect spark plug, and make sure all moving parts have come to a complete stop before removing obstructions, clearing debris, or servicing unit. DO NOT start or operate unit unless all guards and protective covers are properly assembled to unit. NEVER reach into any opening while the engine is running.
CS-4910 EMISSION CONTROL EMISSION CONTROL (EXHAUST & EVAPORATIVE) CARB and EPA Emissions Control Information The emission control system for the engine is EM (engine modification) and, if the second to last character of the Engine Family on the Emission Control Information label (sample below) is “B”, “C”, “K”, or “T”, the emission control system is EM and TWC (3-way catalyst). The fuel tank/fuel line emission control system is EVAP (evaporative emissions).
DESCRIPTION CS-4910 DESCRIPTION Locate the safety decal(s) on your unit. Make sure the decal(s) is legible and that you understand and follow the instructions on it. If a decal cannot be read, a new one can be ordered from your dealer. Safety label is for example only. Your label my appear slightly different.
CS-4910 1. Rear Handle - For Right Hand 2. Choke Control Knob 3. Decompression Device 4. Chain Brake Lever / Front Hand Guard DESCRIPTION 5. Spark Arrester Muffler or Spark Arrester Muffler with Catalyst 6. Spiked Bumper 7. Saw Chain 8. Guide Bar 9. Sprocket Guard Nuts 10. Chain Catcher 11. Chain Tension Adjuster 12. Sprocket / Brake Cover 13. Rear Hand Guard 14. Cylinder Cover 15. Support Handle - For Left Hand 16. Air Cleaner Cover Knob 17. Air Cleaner Cover 18.
CONTENTS CS-4910 CONTENTS The ECHO product you purchased has been factory pre-assembled for your convenience. Due to packaging restrictions, some assembly may be necessary. After opening the carton, check for damage. Immediately notify your retailer or ECHO Dealer of damaged or missing parts. Use the contents list to check for missing parts.
CS-4910 ASSEMBLY Instructions to Install Optional Kick GuardTM to Bar Tools needed: two 11 mm (7/16 in.) wrenches. 1. A Install bolt (A) in rear hole (B) of optional Kick GuardTM and through front hole (C) in guide bar. 2. IMPORTANT: Dimple (D) in optional Kick GuardTM must engage recess (E) in guide bar. 3. Securely tighten nut (F) and bolt (A). D B E C F Guide Bar and Saw Chain Installation / Removal 1. Disconnect spark plug lead. 2. Unlock chain brake (A). 3.
ASSEMBLY CS-4910 5. Mount guide bar (D) on studs (F) and slide toward clutch drum sprocket (G) to make saw chain (E) installation easier. Install saw chain around clutch drum sprocket and guide bar as shown, with cutters on top of guide bar facing forward. 6. Install sprocket guard (C) over guide bar studs (F). Make sure chain tension adjuster pin fits into the guide bar adjuster hole (H), brake band is positioned around clutch drum (F). Tighten sprocket guard nuts finger tight. 7.
CS-4910 3. Hold the bar nose up, and turn the adjuster toward (+) until chain contacts underside of the bar. 4. Tighten nuts with the bar nose held up. 5. Pull the chain around the bar by hand. Loosen the adjustment if you feel tight spots. ASSEMBLY Tighten guide bar nuts to 20-23 N•m (175-200 lbf•in). DO NOT overtighten nuts. Damage to saw may result. 6. Assemble components in reverse order. 7. Keep chain properly tensioned at all times. Note: All chains require frequent adjustments.
OPERATION CS-4910 OPERATION Fuel Diesel fuels and alternative fuels, such as E-15 (15% ethanol), E-85 (85% ethanol) or any fuels not meeting ECHO requirements are NOT approved for use in ECHO 2-stroke gasoline engines. Use of diesel or alternative fuels can cause performance problems, loss of power, overheating, fuel vapor lock, and unintended machine operation, including, but not limited to, improper clutch engagement.
CS-4910 ◆ ◆ ◆ ◆ OPERATION If swallowed, do not induce vomiting. CALL PHYSICIAN OR A POISON CONTROL CENTER IMMEDIATELY. WEAR SAFETY GLASSES when mixing or handling. AVOID repeated or prolonged skin contact. AVOID inhaling oil mists or vapors. ECHO branded 2-stroke oils may be mixed at 50:1 ratio for application in all ECHO engines sold in the past regardless of ratio specified in those manuals. Handling Fuel Fuel is VERY flammable.
OPERATION CS-4910 Mixing Instructions Stored fuel ages. Do not mix more fuel than you expect to use in 30 days, 90 days when a fuel stabilizer is added. 1. Fill an approved fuel container with half of the required amount of gasoline. 2. Add the proper amount of 2-stroke oil to gasoline. 3. Close container and shake to mix oil with gasoline. 4. Add remaining gasoline, close fuel container, and remix. Fuel to Oil Mix – 50:1 Ratio US Metric Gas Oil Gas Oil gal. fl.oz. L cc 1 2.
CS-4910 OPERATION Units equipped with a momentary STOP Switch automatically return to RUN position. Engine can start unintentionally. Always remove spark plug lead from spark plug before assembling or performing maintenance procedures, otherwise, serious personal injury can result. Servicing Fuel and Oil When the fuel tank cap or oil tank cap is difficult to remove, remove the spark plug lead, pull the starter handle slowly, and use the starter handle to assist in removal of the cap.
OPERATION CS-4910 Engine exhaust IS HOT, and contains Carbon Monoxide (CO), a poison gas. Breathing CO can cause unconsciousness, serious injury, or death. Exhaust can cause serious burns. ALWAYS position unit so that exhaust is directed away from your face and body. Operation of this equipment may create sparks that can start fires around dry vegetation. This unit is equipped with a spark arrester to prevent discharge of hot particles from the engine.
CS-4910 OPERATION After choke control knob is pulled and then knob is returned to original position, throttle remains slightly open (fast idle latch condition). ◆ The chain will attempt to move when engine is started with fast idle throttle latch engaged. ◆ Do not start engine before chain brake is locked. Note: Do not squeeze throttle trigger until after chainsaw starts. ◆ 7. Securely hold the chainsaw and pull starter handle (E) several times until first starting sound. 8.
OPERATION CS-4910 11. When engine starts, immediately squeeze and release throttle trigger (F) to disenge throttle latch (G) and returning engine to idle. Pull front hand guard (A) towards the operator immediately (chain brake unlocked position). G F Note: Do not increase engine speed while chain brake (A) is locked. Severe brake damage will result. Starting Warm Engine Make sure the bar and chain are free from any obstruction when starting the chainsaw. 1.
CS-4910 5. Securely hold the chainsaw and pull starter handle (E). 6. Choke (C) may be used if necessary, but after first starting sound, squeeze throttle trigger lock (G) and throttle trigger (F) to release choke (C) and return engine to idle. OPERATION E Note: If engine does not start after five pulls, use cold start procedure. Note: Do not increase engine speed while chain brake (A) is locked. Severe brake damage will result.
OPERATION CS-4910 Stopping 1. Release throttle trigger lock and throttle trigger and allow engine to idle. 2. Move STOP switch (B) down to “STOP” position. Note: If engine does not stop, pull choke control knob out fully to stop engine. Note: Return the unit to your authorized dealer to check and repair STOP switch before starting the engine again. B Checking Chain Tension Chain tension should be checked frequently during work and corrected as necessary. Do not operate with a loose chain.
CS-4910 OPERATION Cutting Instructions General ◆ ◆ ◆ This chainsaw is designed for cutting wood. Do not cut metal, plastic or any non-wood material. Wear suitable hearing protection such as earmuffs or earplugs to protect against objectionable or uncomfortable loud noises. Do not let the tip of the bar touch anything while the engine is running. At cutting speed the chain is moving at a high rate of speed.
OPERATION CS-4910 Start the engine, see that it is running properly. Squeeze the trigger to open the throttle wide open and start the cut. If the chain is properly sharpened, the cutting should be relatively effortless. It is not necessary to press down hard to make the saw cut. Pushing the saw too hard will slow the engine and cutting will actually be more difficult. Sap from palm trees may corrode metal parts unless proper saw maintenance is performed.
CS-4910 OPERATION Felling the Tree A falling tree can seriously damage anything it may hit - a car, a house, a fence, a power line, or another tree. There are ways to make a tree fall where you want it, so first decide where that is! Before cutting, clear the area around the tree. You will need good footing while working and you should be able to work the saw without hitting any obstacles. Next, select a path of retreat.
OPERATION CS-4910 To fell big trees with a diameter exceeding twice the bar length, start 3 the notching cuts from one side and draw the saw through to the other 1 side of the notch. Start the back cut on one side of the tree, pivoting the saw through to form the desired 2 hinge on that side. Then remove the saw for the second cut. Insert the saw in the first cut, very carefully so as not to cause kickback. The final cut is made by drawing the saw forward in the cut to reach the hinge.
CS-4910 OPERATION Bucking Bucking is the sawing of a log or fallen tree into smaller pieces. There are a few basic rules which apply to all bucking operations. Uphill Position • Keep both hands on the handles at all times. • Support logs if possible. • When cutting on a slope or hillside, always stand uphill. Finish cut First cut Support Keep in mind that the wood is heavy and that it will bend and pinch the saw if improperly supported.
OPERATION CS-4910 Use of replacement saw chain and/or guide bar other than that specified, or operation without the optional Kick GuardTM in place, may cause severe kickback resulting in serious injury. Chain and guide bar gauge size must be identical. Use Bar/Chain combinations shown in table above. Kick GuardTM (Optional) To purchase an optional Kick GuardTM contact your ECHO dealer. For the name of the ECHO dealer nearest you, Call: 1-800-432-ECHO (3246) or on the web at www.echo-usa.
CS-4910 MAINTENANCE MAINTENANCE Moving parts can amputate fingers or cause severe injuries. Keep hands, clothing and loose objects away from all openings. Always stop engine, disconnect spark plug, and make sure all moving parts have come to a complete stop before removing obstructions, clearing debris, or servicing unit. Allow unit to cool before performing service. Wear gloves to protect hands from sharp edges and hot surfaces.
MAINTENANCE CS-4910 Maintenance Intervals Units equipped with a Momentary STOP Switch automatically return to RUN position. Engine can start unintentionally. Always remove spark plug lead from spark plug before assembling or performing maintenance procedures, otherwise serious personal injury can result.
CS-4910 MAINTENANCE MAINTENANCE PROCEDURE COMPONENT OR SYSTEM Cylinder Exhaust Port REQUIRED SKILL LEVEL Inspect / Clean / De-carbon 2 Fuel Filter Inspect / Replace * 1 Fuel Cap Gasket Replace * 1 Yearly IMPORTANT NOTE - Time intervals shown are maximum. Actual use and your experience will determine the frequency of required maintenance. MAINTENANCE PROCEDURE NOTES: * Replacement is recommended based on the finding of damage or wear during inspection.
MAINTENANCE CS-4910 3. Start engine and run several minutes to bring to operating temperature. Flash choke twice during warm-up to clear any air from the fuel system. 4. Stop engine. Turn “H” High Speed needle counterclockwise (CCW) to stop. Turn “L” Low Speed needle midway between full clockwise (CW) stop and CCW stop. 5. Idle Speed Adjustment: • Start engine, turn Idle speed adjustment screw “T” CW until the saw chain begins to move, then turn screw out CCW until the saw chain stops moving.
CS-4910 MAINTENANCE Air Filter 1. Check before every use. 2. CLOSE choke ( 3. Remove air cleaner cover (A) and air filter (B). 4. Lightly brush dust off air filter, or clean with compressed air, or replace the air filter. 5. Install air filter and cover. ). A B Spark Plug • Check periodically. • The standard spark gap is 0.65 mm (0.026 in.). • Fastening torque: 15-17 N•m (130-150 lbf•in). 0.65 mm (0.026 in.) 1. Remove air cleaner cover and remove spark plug. 2.
MAINTENANCE CS-4910 Fuel Filter • Check periodically. • Do not allow dust to enter fuel tank. • A clogged filter (A) will cause difficulty in starting engine or abnormalities in engine performance. 1. Pull filter out through gas port, and inspect filter. A Do not damage fuel line while removing fuel filter from tank. 2. When the filter is dirty, replace it as follows: 3. Do not remove the wire coil clamp to remove the fuel filter.
CS-4910 MAINTENANCE Automatic Oiler • The discharge volume of the automatic oiler is adjusted to approximately 4 mL/min at 7000 r/min, prior to shipment from factory. • Always check oil discharge when in use. • Turn adjusting screw (A) counterclockwise to increase oil volume, clockwise to decrease oil volume. A • Do not turn the adjusting screw beyond the maximum or minimum limit of volume adjustment. Oil Filter • Check periodically. • Do not allow dust to enter into oil tank.
MAINTENANCE CS-4910 Guide Bar 1. Clean before using. 2. Clean the groove of guide bar (A) with a small screwdriver. 3. Clean oil holes (B) with a wire. 4. Invert guide bar periodically. 5. Clean the guide bar mount area before installing the guide bar. B A B Sprocket • A damaged sprocket will cause premature damage or wear of saw chain. Worn: 0.5 mm (0.020 in.) • When the sprocket has worn 0.5 mm (0.020 in.) or more, replace it. • Check sprocket when you install new chain.
CS-4910 MAINTENANCE Cooling System Cleaning • Check periodically. • Clogged fins will result in poor engine cooling. 1. Remove air cleaner cover and cylinder cover. 2. Use compressed air or wooden tool to remove dirt and dust from between fins to let cooling air pass easily. Spark Arrester Muffler • The spark arrester muffler controls the exhaust noise and prevents hot, glowing particles of carbon from leaving the muffler.
MAINTENANCE CS-4910 Spark Arrester Screen Carbon deposits in muffler will cause drop in engine output and overheating. Spark arrester screen must be checked periodically. 1. Remove air cleaner cover and remove spark plug lead. 2. Remove spark arrester cover (A) and screen (B) from muffler (C) body. 3. Clean carbon deposits from muffler components. 4. Replace screen if it is cracked, or has holes burned through. 5. Assemble components in reverse order.
CS-4910 MAINTENANCE • Drive link serves to remove sawdust from the groove of the guide bar. Keep the lower edge of the drive link sharp where indicated. Sharpen lower edge Setting Saw Chain • For setting saw chain, round file (5.0 mm [3/16 in.] diameter) and flat file are used. • Push file as shown. 25° LPX 30° BPX Keep this angle • To keep correct position and correct angle, use a file holder. • Hold the file horizontally.
MAINTENANCE CS-4910 • Be sure to round off the front edge of the depth gauge. Depth gauge tool • Properly filed cutters are shown in illustration. • When setting of the chain is finished, soak it in oil and wash away filings completely before using. 25° LPX 30° BPX Top plate filing angle • When chain has been filed on the bar, supply sufficient oil to it, move the chain slowly to wash away the filings before using again. 60° LPX 70° BPX Side plate filing angle 0.65 mm (0.025 in.
CS-4910 TROUBLESHOOTING TROUBLESHOOTING ENGINE PROBLEM TROUBLESHOOTING CHART Problem Check Fuel at carburetor Status Cause Remedy No fuel at carburetor Fuel strainer or fuel line obstructed Clean or replace No fuel at cylinder Carburetor See your dealer See your dealer OPEN choke Engine starts hard Fuel at cylinder Muffler wet with fuel Fuel mixture too rich or Engine does not start Adjust carburetor See your dealer Spark at end of plug wire No spark Spark at plug Engine runs, but dies
STORAGE CS-4910 ENGINE PROBLEM TROUBLESHOOTING CHART Problem Check Status Engine runs, but dies Spark plug Plug dirty or worn Normal wear Clean and adjust or replace Carburetor Improper adjustment Vibration Adjust or Cooling system Cooling system dirty or plugged Extended operation in dirty or dusty locations Clean Spark arrester screen Spark arrester screen plugged Normal wear Replace Internal engine problem See your dealer Engine does not accelerate properly Engine does not crank
CS-4910 SPECIFICATIONS • Drain fuel tank completely. Press purge bulb six to seven times to remove remaining fuel from carburetor then drain the tank again. Close choke, start and run the engine until it stops due to lack of fuel. • Allow engine to cool. Remove the spark plug lead from the spark plug. Remove the spark plug. Pour 7 cc (0.25 oz.) of fresh, clean, two-stroke engine oil into the cylinder through the spark plug hole. • Store in a dry area, free from dust.
PRODUCT REGISTRATION CS-4910 MODEL CS-4910 Use 89 octane unleaded. Do not use fuel containing methyl alcohol, more than 10% ethyl Gasoline alcohol or 15% MTBE. Do not use alternative fuels such as E-15 or E-85. ISO-L-EGD (ISO/CD 13738) and JASO M345Oil FD two-stroke, air-cooled engine oil. Oiling system Adjustable automatic oiler Chain oil capacity 280 ml (9.47 US. fl. oz.) Starter system Automatic rewind starter Clutch Centrifugal type Sprocket type Rim type, 7-tooth, 0.325 in.
PRODUCT REGISTRATION ECHO Incorporated CS-4910 X7503314201 © 05/22 ECHO Incorporated 57
NOTES CS-4910 NOTES 58 X7503314201 © 05/22 ECHO Incorporated
CS-4910 X7503314201 © 05/22 ECHO Incorporated NOTES 59
C38515001001 - C38515999999 ECHO INCORPORATED 400 Oakwood Road Lake Zurich, IL 60047 www.echo-usa.
