Honda HHT31S Owner's Manual

Honda trimmer/brush cutter owner's manual
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Owner's Manual
Trimmer/Brush Cutter
See page 42 for instructions on
assembling your Trimmer.
© 2002 American Honda Motor Co., Inc.—All Rights Reserved



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  • Page 1 Owner's Manual Trimmer/Brush Cutter HHT25S • HHT31S See page 42 for instructions on assembling your Trimmer. © 2002 American Honda Motor Co., Inc.—All Rights Reserved...
  • Page 2 Keep this owner’s manual handy, so you can refer to it at any time. This owner’s manual is considered a permanent part of the trimmer/brush cutter and should remain with the trimmer/brush cutter if resold. The information and specifications included in this publication were in effect at the time of approval for printing.
  • Page 3 We want to help you get the best results from your new trimmer/brush cutter and to operate it safely. This manual contains the information on how to do that; please read it carefully.
  • Page 4 INTRODUCTION A FEW WORDS ABOUT SAFETY Your safety, and the safety of others, are very important. And using this trimmer/brush cutter safely is an important responsibility. To help you make informed decisions about safety, we have provided operating procedures and other information on labels and in this manual.
  • Page 5: Table Of Contents

  • Page 6: Trimmer Safety

    TRIMMER SAFETY IMPORTANT SAFETY INFORMATION The Honda HHT25S and HHT31S trimmer/brush cutters are designed to cut grass, weeds, brush, and/or wood if equipped with an appropriate cutting attachment. Other uses can result in injury to the operator or damage to the trimmer and other property.
  • Page 7: Attachments & Modifications

    As an employer, you have special responsibilities to the people who work for you. Before you ask anyone to operate this trimmer/ brush cutter, you need to determine whether the operator is old enough, large enough, and strong enough to safely handle and control the trimmer/ brush cutter.
  • Page 8: Safety Label Locations

    The labels shown here contain important safety information. Please read them carefully. These labels are considered permanent parts of your trimmer/brush cutter. If a label comes off or becomes hard to read, contact an authorized Honda servicing dealer for a replacement.
  • Page 9: Recommended Cutting Attachments

    RECOMMENDED CUTTING ATTACHMENTS CUTTING-LINE HEADS AND SHIELDS A cutting-line head containing nylon monofilament line, and a debris shield with cutoff knife is standard equipment. The shield’s cutoff knife automatically removes any excess line that is released from the cutting head. Honda HHT31SUNBA model trimmers are supplied with two different debris shields.
  • Page 10: Blades And Shields

    RECOMMENDED CUTTING ATTACHMENTS BLADES AND SHIELDS A variety of blades are available from your Honda trimmer servicing dealer. Always use a debris shield designed for use with a blade when attaching a blade to your trimmer. The blade type debris shield does not have a cutoff knife. Honda HHT31SUNBA trimmers are supplied with a blade cover surrounding the edge of the blade.
  • Page 11: Cutting Attachment Applications

    Remove the blade cover in the reverse order of installation. CUTTING ATTACHMENT APPLICATIONS HHT25S HHT31S GRASS AND LIGHT WEEDS THICK WEEDS AND LIGHT BRUSH WOODY BRUSH, SHRUBS, SAPLINGS Your Honda trimmer servicing dealer has cutting attachments that have been designed and approved for your trimmer and are covered by warranty.
  • Page 12: Controls & Equipment

  • Page 13: Controls

    CONTROLS The location and operation of the controls are similar on both the HHT25S and HHT31S models. Choke Lever The choke lever opens and closes the choke valve. The CLOSED position enriches the fuel mixture for starting a cold engine.
  • Page 14 CONTROLS & EQUIPMENT Throttle Set Button The throttle set button is used to hold the throttle trigger at the fast idle position for starting. Do not allow the cutting line or blade to contact any obstruction when starting the engine with the throttle set button engaged.
  • Page 15: Equipment

    CONTROLS & EQUIPMENT EQUIPMENT FULL SHOULDER HARNESS (UNBA only) The Honda HHT25S and HHT31S trimmer/brush cutters are supplied with a shoulder harness and safety glasses. Refer to page 14 for a description of other equipment and protective clothing you will need.
  • Page 16: Before Operation

    BEFORE OPERATION ARE YOU READY TO OPERATE THE TRIMMER? Your safety is your responsibility. A little time spent in preparation will significantly reduce your risk of injury. Knowledge Read and understand this manual. Know what the controls do and how to operate them. Familiarize yourself with the trimmer and its operation before you begin to use it.
  • Page 17 IS YOUR TRIMMER READY TO GO? For your safety, and to maximize the service life of your equipment, it is very important to take a few moments before you operate the trimmer to check its condition. Be sure to take care of any problem you find, or have your servicing dealer correct it, before you operate the trimmer.
  • Page 18 BEFORE OPERATION ARE YOUR SHOULDER HARNESS AND TRIMMER CORRECTLY ADJUSTED? Adjusting the Harness Adjust the harness so the quick-release latch is at your right hip, as shown. QUICK-RELEASE LATCH FULL SHOULDER HARNESS QUICK-RELEASE LATCH SINGLE-STRAP SHOULDER HARNESS Balancing the Trimmer on the Shoulder Harness Hang the trimmer on the harness hook, and see how it balances.
  • Page 19: Operation

    OPERATION SAFE OPERATING PRECAUTIONS Before operating the trimmer for the first time, please review the IMPORTANT SAFETY INFORMATION chapter on page 4 and BEFORE OPERATION chapter starting on page 14. Even if you have operated other trimmers, take time to become familiar with the operation of this trimmer’s controls and handling.
  • Page 20 OPERATION 5. Set the trimmer on the ground, resting on the debris shield and the fuel tank guard. Do not allow the cutting-line or blade to contact any obstruction. Always rest the trimmer on the ground for starting, rather than holding it in the operating position.
  • Page 21: Stopping The Engine

    STOPPING THE ENGINE 1. Release the throttle trigger. 2. Move the ignition switch to the STOP (O) position. Wait for the cutting line head or blade to stop before allowing the end of the trimmer to contact anything. WARNING  The blade will continue to spin briefly after the engine has stopped or the throttle trigger is released.
  • Page 22 OPERATION Throttle Operation Pull the throttle trigger toward the grip to increase engine speed and start cutting attachment rotation. The trimmer has the greatest cutting force at maximum engine speed. Release the throttle trigger to reduce engine speed. At idle, the cutting attachment should coast to a stop.
  • Page 23: Safe Operating Practices

    The trimmer will throw debris in the direction of blade movement at the point of contact. The cutting line head or blade on Honda HHT25S and HHT31S trimmers rotate counterclockwise, as viewed from the operator’s position, so tilting the cutting line head to the right will throw debris away from you, and tilting to the left will throw debris toward you.
  • Page 24: Operating Tips

    Blades on Honda HHT25S and HHT31S trimmers rotate counterclockwise, as viewed from the operator’s position. Therefore, the left side of the blade is moving toward you. With these trimmers, sawing with the left side of a brush blade will give you better control and less risk of kickback, though it will throw the sawdust toward you.
  • Page 25 OPERATION Trimming and Edging Use nylon line for cutting against a hard surface. Work from an angle where debris that strikes the hard surface will ricochet away from you. DEBRIS Avoid contact with wires, wire fences, metal rods, etc. Overlapping a wire will cause the nylon line to wrap around the wire and break off.
  • Page 26: Servicing Your Honda Trimmer

    SERVICING YOUR HONDA TRIMMER THE IMPORTANCE OF MAINTENANCE Good maintenance is essential for safe, economical, and trouble-free operation. It will also help reduce air pollution. WARNING  Improperly maintaining this trimmer, or failure to correct a problem before operation, can cause a malfunction in which you can be seriously hurt or killed.
  • Page 27: Maintenance Schedule

    Throttle cable Cutting attachment Debris shield Nuts, bolts, fasteners Shoulder harness quick-release Drive cable Idle speed HHT25S Valve clearance HHT31S Spark plug Spark arrester Combustion chamber Gear case Clutch shoes and drum Fuel filter Fuel tank Fuel tubes Oil tube (HHT25S only) Engine cooling fins (1) Service more frequently when used in dusty areas.
  • Page 28: Engine

    (see page 27). HHT25S 2.7 fl oz (80 cc) Engine oil capacity: HHT31S 3.4 fl oz (100 cc) 3. Screw in the filler cap/dipstick securely. FILLER OPENING (HHT31S) OIL FILLER...
  • Page 29 3. Wipe dirt from the air cleaner base and cover using a moist rag. Be careful to prevent dirt from entering the carburetor. SERVICING YOUR HONDA TRIMMER FILTER LATCH RETAINING TABS AIR CLEANER COVER HHT25S RETAINING TABS AIR CLEANER COVER LATCH HHT31S FILTER...
  • Page 30 Throttle Cable Adjustment 1. Loosen the lock nut with a 10 mm wrench, and turn the adjusting nut in or out as required. 2. Tighten the lock nut and recheck cable free play. HHT31S LOCK NUT CABLE END FREE PLAY 1/16 ~ 1/8 in (1.0 –...
  • Page 31: Cutting Attachments

    Honda trimmers come standard with low noise line. Using non-Honda line may result in increased noise levels. For original, factory-installed Honda cutting-line heads, use only nylon monofilament line in the line sizes shown below. Line Size Model HHT25S HHT31S 0.095" 0.105"...
  • Page 32 SERVICING YOUR HONDA TRIMMER Manual Cutting-Line Head 1. Clean any mud, dirt, debris, etc. from the area around the trimmer head; otherwise, it will make it more difficult to service. 2. Rotate the left-hand threaded knob in the direction of the arrow and remove the knob. Remove the spring and spool from the housing then remove any remaining old line from the spool.
  • Page 33 5. When you have about 6 inches (150 mm) of line remaining, press the lines into the two notches on the bottom of the spool. This will hold the lines on the spool for reassembly. 6. Feed both line ends through the metal eyelets in the housing.
  • Page 34 SERVICING YOUR HONDA TRIMMER Semi-Matic (Bump-Feed) Cutting-Line Head 1. Clean any mud, dirt, debris, etc., from around the trimmer head area; otherwise, it will make it more difficult to service. 2. Locate the half-round locking hole on the spool. 3. It may be necessary to lightly rotate the spool in the direction of the arrow about an 1/8 turn until the spool stops.
  • Page 35 7. Wind both lines tightly and evenly from side to side ignoring the ridge. Feed the line while turning the spool in the direction of the arrow. Do not allow the line to get twisted. It is important to prevent the two lines from getting twisting over each other.
  • Page 36 SERVICING YOUR HONDA TRIMMER Removal & Installation This section shows you how to remove and install either style trimmer head from your trimmer. 1. Insert the tip of a commercially available 4 mm hex wrench or equivalent fully into the gear case hole.
  • Page 37 Blade Blade Inspection Always wear gloves when working around the blade. Before each use, check the blade for wear and damage, and check the tightness of the blade lock nut. Examine the entire head area, including the debris shield, and clear or clean it free from dirt, debris, loose string, wire, or any other foreign materials.
  • Page 38 SERVICING YOUR HONDA TRIMMER 1. Install the protective plastic cover, that came with the blade, back on the blade. 2. Insert a commercially available 4 mm hex tool or equivalent fully into the gear case hole. 3. Turn the blade until you feel the tool drop into the hole in cover plate/spacer A.
  • Page 39 Spark Plug Service Recommended spark plugs: HHT25S CMR5HSB (NGK) HHT31S CR5HSB (NGK) U16FSR-UB (DENSO) NOTICE Incorrect spark plugs can cause engine damage. 1. HHT25S model: Remove the 5 x 12 mm hex bolt and top cover. 2. Disconnect the spark plug cap, and remove any dirt from around the spark plug area.
  • Page 40 SERVICING YOUR HONDA TRIMMER Spark Arrester Service HHT31S The spark arrester must be serviced every 100 hours to keep it functioning as designed. If the engine has been running, the muffler will be very hot. Allow the muffler to cool before servicing the spark arrester.
  • Page 41 HHT25S The spark arrester must be serviced every 100 hours to keep it functioning as designed. If the engine has been running, the muffler will be very hot. Allow the muffler to cool before servicing the spark arrester. 1. Remove the 5 x 12 mm hex bolt and top cover 2.
  • Page 42: Fuel System

    Refueling Fuel tank capacities: HHT25S: 0.53 qt/16.9 fl oz (0.50 ) HHT31S: 0.69 qt/22.0 fl oz (0.65 ) Check the fuel level by looking through the translucent fuel tank. If the fuel level is low, refuel in a well-ventilated area with the engine stopped.
  • Page 43 Inspect the engine cooling fins, and clean out any dirt and debris. On both the HHT25S and HHT31S, it is necessary to remove the top cover. Removal procedures are located on page 37 for HHT25S and page 38 for the HHT31S.
  • Page 44: Assembly

    ASSEMBLY After assembly and before operation review the Safe Operating Precautions on page 17. IMPORTANCE OF PROPER ASSEMBLY Proper assembly is essential to operator safety and the reliability of the machine. Any error or oversight made by the person assembling and servicing a machine can result in faulty operation, damage to the machine, or injury to the operator.
  • Page 45: Unpacking

    Saw blade, 50 tooth/10 in Blade cover UNBA types types Qty. only only • OWNER'S MANUAL Trimmer/Brush Cutter HHT25S • HHT31S • • • © 2002 American Honda Motor Co., Inc. – All Rights Reserved • • • • • •...
  • Page 46: Trimmer Assembly (Unba Types Only)

    ASSEMBLY TRIMMER ASSEMBLY (UNBA types only) U-Shaped Handlebar Installation 1. Remove the four 5 x 28 mm bolt/washers and handlebar holder A. 2. Set the U-shaped handle into handlebar holder B with the throttle trigger facing to the right. 3. Adjust the handlebar position as shown. 4.
  • Page 47 Saw Blade The UNBA types are shipped with a manual nylon cutting-line head installed on the trimmer. If the saw blade is needed, move the ignition switch to the STOP (O) position and disconnect the spark plug cap from the spark plug. Wear protective gloves when working around the cutting-line head and saw blade. Cutting-Line Head Removal 1.
  • Page 48 ASSEMBLY Saw Blade Installation 1. Insert a 4 mm hex wrench or equivalent into the gear case hole to prevent the output shaft from turning. 2. Install cover plate/spacer A onto the output shaft as shown. 3. With the blade cover installed on the blade, install the blade, by aligning the center of the blade with the shoulder on cover plate/spacer 4.
  • Page 49: Blade Cover Removal

    BLADE COVER REMOVAL 1. Turn the blade cover slowly until the cover latch is clear of the debris shield. Unfasten the latch by lifting the tab off the post. 2. Pull the post end away from the blade and set it on top of the blade as shown. 3.
  • Page 50: Engine Oil

    Do not overfill, as the engine oil tank capacity is small. Engine oil capacity: HHT25S 2.7 fl oz (80 cc) HHT31S 3.4 fl oz (100 cc) NOTICE Running the engine with too little or too much oil can cause engine damage.
  • Page 51: Storage

    STORAGE STORAGE PREPARATION Proper storage preparation is essential to keep your trimmer trouble free and looking good. The following steps will help to keep rust and corrosion from impairing your trimmer's function and appearance, and will make the engine easier to start when you use the trimmer again.
  • Page 52: Storage Precautions

    STORAGE Adding Fuel Stabilizer to Extend Fuel Storage Life When adding a fuel stabilizer, fill the fuel tank with fresh gasoline. If only partially filled, air in the tank will promote fuel deterioration during storage. If you keep a container of gasoline for refueling, be sure that it contains only fresh gasoline.
  • Page 53: Transporting

    TRANSPORTING BEFORE LOADING If the engine has been running, allow it to cool for at least 15 minutes before loading the trimmer on the transport vehicle. A hot engine and exhaust system can burn you and can ignite some materials. Always turn the ignition switch to the STOP (O) position.
  • Page 54: Taking Care Of Unexpected Problems

    TAKING CARE OF UNEXPECTED PROBLEMS STARTING PROBLEMS Engine Will Not Start Check control positions. Check fuel. Remove spark plug. Take trimmer to an authorized Honda servicing dealer, or refer to shop manual. ENGINE OPERATING PROBLEMS Low Power or Engine Speed Won’t Increase Check air filter.
  • Page 55: Cutting Head Problems

    CUTTING HEAD PROBLEMS Blade or Cutting-line head Won’t Stop Turning When Throttle is at SLOW Position Check throttle control and cable. Check clutch. Blade or Cutting-Line Head Won’t Turn Check clutch, drive cable, and gear case. Excessive Vibration Check cutting-line head or blade nut.
  • Page 56: Technical & Consumer Information

    ENGINE SERIAL NUMBER HHT31S Carburetor Modifications for High Altitude Operation At high altitude, the standard carburetor air-fuel mixture will be too rich. Performance will decrease, and fuel consumption will increase. A very rich mixture will also foul the spark plug and cause hard starting.
  • Page 57 Oxygenated Fuels Some conventional gasolines are being blended with alcohol or an ether compound. These gasolines are collectively referred to as oxygenated fuels. To meet clean air standards, some areas of the USA and Canada use oxygenated fuels to help reduce emissions. If you use an oxygenated fuel, be sure it is unleaded and meets the minimum octane rating requirement.
  • Page 58 TECHNICAL & CONSUMER INFORMATION Emissions Control System Information Source of Emissions The combustion process produces carbon monoxide, oxides of nitrogen, and hydrocarbons. Control of hydrocarbons and oxides of nitrogen is very important because, under certain conditions, they react to form photochemical smog when subjected to sunlight.
  • Page 59 Descriptive Term Moderate Intermediate Extended The Air Index Information hang tag/label must remain on the trimmer/brush cutter until it is sold. Remove the hang tag before operating the trimmer/brush cutter. TECHNICAL & CONSUMER INFORMATION Applicable to Emissions Durability Period 50 hours (0–65 cc) 125 hours (greater than 65 cc) 125 hours (0–65 cc)
  • Page 60 HHT25S Manual feed — head Semi-matic 6.12 feet (1.867 m) feed head — — 9.6 in (245 mm) — 13.0 lb. (5.89 kg) — HHT31S HHT31SUNBA • • • • optional • • optional optional • HHT31S 6.15 feet (1.875 m) 6.18 feet (1.885 m)
  • Page 61 Clutch Drive Type Tuneup ITEM Spark plug gap HHT25S Valve clearance (cold) HHT31S TECHNICAL & CONSUMER INFORMATION ENGINE HHT25S GX25 1.5 cu in (25 cc) 1.4 x 1.0 in (35 x 26 mm) • m) at 5,000 rpm Transistorized magneto...
  • Page 62: Consumer Information

    Call (800) 426-7701 or visit our website: Warranty Service Information Honda Power Equipment dealership personnel are trained professionals. They should be able to answer any question you may have. If you encounter a problem that your dealer does not solve to your satisfaction, please discuss it with the dealership's management.
  • Page 63: Index

    INDEX Air Filter Check ... 27 Cleaning ... 27 Air Index... 57 Assembly ... 42 Loose Parts ... 43 Trimmer Assembly (UNBA types only)... 44 Unpacking ... 43 Before Operation ... 14 Blade Inspection ... 35 Removal and Installation ... 35 Blade Thrust ...
  • Page 64 INDEX Maintenance Air Filter ... 27 Engine Oil... 26 Fuel System ... 40 Importance ... 24 Safety ... 24 Schedule ... 25 Spark Arrester ... 38 Spark Plug... 37 Throttle Cable... 28 Oil, Engine Changing ... 26 Level Check... 26 Recommendations ...
  • Page 65: Quick Reference Information

    Check debris shield (pages 29 and 36) Check nuts, bolts, fasteners Check shoulder harness, quick release (page 19) Change engine oil (page 26) Refer to the Maintenance Schedule (page 25) HHT31S 0.69 qt/22.0 fl oz (0.65l) 3.4 fl oz (100 cc) NGK: CR5HSB DENSO: U16FSR-UB...
  • Page 66 POM53509 31VJ4000 IPC 10000.2002.10 Printed on Printed in U.S.A. 00X31-VJ4-0000 Recycled Paper...

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