OPERATOR’S MANUAL 21” Self-Propelled Mower Model Number 979 IMPORTANT: READ SAFETY RULES AND INSTRUCTIONS CAREFULLY Warning: This unit is equipped with an internal combustion engine and should not be used on or near any unimproved forestcovered, brush-covered or grass-covered land unless the engine’s exhaust system is equipped with a spark arrester meeting applicable local or state laws (if any). If a spark arrester is used, it should be maintained in effective working order by the operator. In the State of California the above is required by law (Section 4442 of the California Public Resources Code). Other states may have similar laws. Federal laws apply on federal lands. A spark arrester for the muffler is available through your nearest engine authorized service dealer or contact the service department, P.O. Box 368022 Cleveland, Ohio 44136-9722. MTD PRODUCTS INC. P.O. BOX 368022 CLEVELAND, OHIO 44136-9722 PRINTED IN U.S.A. FORM NO. 770-10075B.fm (10/00) TABLE OF CONTENTS Content Page Important Safe Operation Practices................................................................... 3 Slope Gauge...................................................................................................... 6 Assembling Your Lawn Mower........................................................................... 7 Know Your Lawn Mower .................................................................................... 8 Operating Your Lawn Mower ............................................................................. 9 Making Adjustments .......................................................................................... 11 Maintaining Your Lawn Mower........................................................................... 12 Troubleshooting ................................................................................................. 16 Parts List............................................................................................................ 18 FINDING MODEL NUMBER This Operator’s Manual is an important part of your new lawn mower. It will help you assemble, prepare and maintain the unit for best performance. Please read and understand what it says. Before you start assembling your new equipment, please locate the model plate on the equipment and copy the information from it in the space provided below. The information on the model plate is very important if you need help from our Customer Support Department or an authorized dealer. • You can locate the model number by looking down at the rear of the deck. A sample model plate is explained below. For future reference, please copy the model number and the serial number of the equipment in the space below. (Model Number) (Serial Number) Copy the model number here: Copy the serial number here: MTD PRODUCTS INC CLEVELAND, OHIO 44136 CALLING CUSTOMER SUPPORT If you have difficulty assembling this product or have any questions regarding the controls, operation or maintenance of this unit, please call the Customer Support Department. Call 1- (330) 220-4MTD (4683) or 1- (800)-800-7310 to reach a Customer Support representative. Please have your unit’s model number and serial number ready when you call. See previous section to locate this information. You will be asked to enter the serial number in order to process your call. For more details about your unit, visit our website at www.yardman.com 2 SECTION 1: IMPORTANT SAFE OPERATION PRACTICES WARNING: This symbol points out important safety instructions which, if not followed, could endanger the personal safety and/or property of yourself and others. Read and follow all instructions in this manual before attempting to operate this machine. Failure to comply with these instructions may result in personal injury. When you see this symbol - heed its warning. WARNING: Engine Exhaust, some of its constituents, and certain vehicle components contain or emit chemicals known to State of California to cause cancer and birth defects or other reproductive harm. DANGER: This machine was built to be operated according to the rules for safe operation in this manual. As with any type of power equipment, carelessness or error on the part of the operator can result in serious injury. This machine is capable of amputating hands and feet and throwing objects. Failure to observe the following safety instructions could result in serious injury or death. General Operation 1. 2. 3. 4. 5. 6. 7. 8. Read this operator’s manual carefully in its entirety before attempting to assemble this machine. Read, understand, and follow all instructions on the machine and in the manual(s) before operation. Be completely familiar with the controls and the proper use of this machine before operating it. Keep this manual in a safe place for future and regular reference and for ordering replacement parts. This machine is a precision piece of power equipment, not a plaything. Therefore, exercise extreme caution at all times. Your unit has been designed to perform one job: to mow grass. Do not use it for any other purpose. Never allow children under 14 years old to operate this machine. Children 14 years old and over should read and understand the operation instructions and safety rules in this manual and should be trained and supervised by a parent. Only responsible individuals who are familiar with these rules of safe operation should be allowed to use this machine. Thoroughly inspect the area where the equipment is to be used. Remove all stones, sticks, wire, bones, toys and other foreign objects which could be tripped over or picked up and thrown by the blade. Thrown objects can cause serious personal injury. Plan your mowing pattern to avoid discharge of material toward roads, sidewalks, bystanders and the like. Also, avoid discharging material against a wall or obstruction which may cause discharged material to ricochet back toward the operator. To help avoid blade contact or a thrown object injury, stay in the operator zone behind the handles and keep children, bystanders, helpers and pets at least 75 feet from the mower while it is in operation. Stop machine if anyone enters the area. Always wear safety glasses or safety goggles during operation and while performing an adjustment or repair to protect your eyes. Thrown objects which ricochet can cause serious injury to the eyes. Wear sturdy, rough-soled work shoes and close-fitting slacks and shirts. Shirts and pants that cover the arms and legs and steel-toed shoes are recommended. Never operate this machine in bare feet, sandals, slippery or light weight (e.g. canvas) shoes. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 3 Do not put hands or feet near rotating parts or under the cutting deck. Contact with the blade can amputate hands and feet. A missing or damaged discharge cover can cause blade contact or thrown object injuries. Many injuries occur as a result of the mower being pulled over the foot during a fall caused by slipping or tripping. Do not hold on to the mower if you are falling; release the handle immediately. Never pull the mower back toward you while you are walking. If you must back the mower away from a wall or obstruction first look down and behind to avoid tripping and then follow these steps: a. Step back from the mower to fully extend your arms. b. Be sure you are well balanced with sure footing. c. Pull the mower back slowly, no more than half way toward you. d. Repeat these steps as needed. Do not operate the mower while under the influence of alcohol or drugs. Do not engage the self-propelled mechanism on units so equipped while starting engine. The blade control handle is a safety device. Never attempt to bypass its operation. Doing so makes the safety device inoperative and may result in personal injury through contact with the rotating blade. The blade control handle must operate easily in both directions and automatically return to the disengaged position when released. Never operate the mower in wet grass. Always be sure of your footing. A slip and fall can cause serious personal injury. If you feel you are losing your footing, release the blade control handle immediately and the blade will stop rotating within three seconds. Mow only in daylight or in good artificial light. Walk, never run. Stop the blade when crossing gravel drives, walks or roads. If the equipment should start to vibrate abnormally, stop the engine and check immediately for the cause. Vibration is generally a warning of trouble. Shut the engine off and wait until the blade comes to a complete stop before removing the grass catcher or 20. 21. 22. 23. unclogging the chute. The cutting blade continues to rotate for a few seconds after the engine is shut off. Never place any part of the body in the blade area until you are sure the blade has stopped rotating. Never operate mower without proper trail shield, discharge cover, grass catcher, blade control handle or other safety protective devices in place and working. Never operate mower with damaged safety devices. Failure to do so, can result in personal injury. Muffler and engine become hot and can cause a burn. Do not touch. Only use parts and accessories made for this machine by the manufacturer. Failure to do so, can result in personal injury. If situations occur which are not covered in this manual, use care and good judgment. Contact your dealer for assistance. Telephone 1-800-800-7310 for the name of your nearest dealer. 5. 6. Service Safe Handling Of Gasoline: 1. 2. 3. 4. Slope Operation Slopes are a major factor related to slip and fall accidents which can result in severe injury. Operation on slopes requires extra caution. If you feel uneasy on a slope, do not mow it. For your safety, use the slope gauge included as part of this manual to measure slopes before operating this unit on a sloped or hilly area. If the slope is greater than 15 degrees, do not mow it. 5. Do: 1. 2. 3. 6. Mow across the face of slopes; never up and down. Exercise extreme caution when changing direction on slopes. Watch for holes, ruts, rocks, hidden objects, or bumps which can cause you to slip or trip. Tall grass can hide obstacles. Always be sure of your footing. A slip and fall can cause serious personal injury. If you feel you are losing your balance, release the blade control handle immediately, and the blade will stop rotating within 3 seconds. 7. 8. 9. 10. Do Not: 1. 2. 3. obscure your vision of a child who may run into the mower. Keep children away from hot or running engines. They can suffer burns from a hot muffler. Never allow children under 14 years old to operate a power mower. Children 14 years old and over should read and understand the operation instructions and safety rules in this manual and should be trained and supervised by a parent. Do not mow near drop-offs, ditches or embankments, you could lose your footing or balance. Do not mow slopes greater than 15 degrees as shown on the slope gauge. Do not mow on wet grass. Unstable footing could cause slipping. 11. 12. 13. Children 14. Tragic accidents can occur if the operator is not alert to the presence of children. Children are often attracted to the mower and the mowing activity. They do not understand the dangers. Never assume that children will remain where you last saw them. 1. Keep children out of the mowing area and under the watchful care of a responsible adult other than the operator. 2. Be alert and turn mower off if a child enters the area. 3. Before and while moving backwards, look behind and down for small children. 4. Use extreme care when approaching blind corners, doorways, shrubs, trees, or other objects that may 15. To avoid personal injury or property damage use extreme care in handling gasoline. Gasoline is extremely flammable and the vapors are explosive. Serious personal injury can occur when gasoline is spilled on yourself or your clothes which can ignite. Wash your skin and change clothes immediately. Use only an approved gasoline container. Never fill containers inside a vehicle or on a truck or trailer bed with a plastic liner. Always place containers on the ground away from your vehicle before filling. When practical, remove gas-powered equipment from the truck or trailer and refuel it on the ground. If this is not possible, then refuel such equipment on a trailer with a portable container, rather than from a gasoline dispenser nozzle. Keep the nozzle in contact with the rim of the fuel tank or container opening at all times until fueling is complete. Do not use a nozzle lock-open device. Extinguish all cigarettes, cigars, pipes and other sources of ignition. Never fuel machine indoors because flammable vapors will accumulate in the area. Never remove gas cap or add fuel while the engine is hot or running. Allow engine to cool at least two minutes before refueling. Never over fill fuel tank. Fill tank to no more than ½ inch below bottom of filler neck to provide space for fuel expansion. Replace gasoline cap and tighten securely. If gasoline is spilled, wipe it off the engine and equipment. Move unit to another area. Wait 5 minutes before starting the engine. Never store the machine or fuel container inside where there is an open flame, spark or pilot light as on a water heater, space heater, furnace ,clothes dryer or other gas appliances. To reduce fire hazard, keep mower free of grass, leaves, or other debris build-up. Clean up oil or fuel spillage and remove any fuel soaked debris. Allow a mower to cool at least 5 minutes before storing. General Service: 1. 2. 4 Never run an engine indoors or in a poorly ventilated area. Engine exhaust contains carbon monoxide, an odorless and deadly gas. Before cleaning, repairing, or inspecting, make certain the blade and all moving parts have stopped. Disconnect the spark plug wire and ground against the engine to prevent unintended starting. 3. 4. 5. 6. 7. 8. Check the blade and engine mounting bolts at frequent intervals for proper tightness. Also, visually inspect blade for damage (e.g., bent, cracked, worn) Replace blade with the original equipment manufacture’s (O.E.M.) blade only, listed in this manual. “Use of parts which do not meet the original equipment specifications may lead to improper performance and compromise safety!” Mower blades are sharp and can cut. Wrap the blade or wear gloves, and use extra caution when servicing them. Keep all nuts, bolts, and screws tight to be sure the equipment is in safe working condition. Never tamper with safety devices. Check their proper operation regularly. After striking a foreign object, stop the engine, disconnect the spark plug wire and ground against the engine. Thoroughly inspect the mower for any damage. Repair the damage before starting and operating the mower. Never attempt to make a wheel or cutting height adjustment while the engine is running. 9. Grass catcher components, discharge cover, and trail shield are subject to wear and damage which could expose moving parts or allow objects to be thrown. For safety protection, frequently check components and replace immediately with original equipment manufacturer’s (O.E.M.) parts only, listed in this manual. “Use of parts which do not meet the original equipment specifications may lead to improper performance and compromise safety!” 10. Do not change the engine governor setting or overspeed the engine. The governor controls the maximum safe operating speed of the engine. 11. Maintain or replace safety and instruction labels, as necessary. 12. Observe proper disposal laws and regulations. Improper disposal of fluids and materials can harm the environment. WARNING - YOUR RESPONSIBILITY: Restrict the use of this power machine to persons who read, understand and follow the warnings and instructions in this manual and on the machine. NOTE: Not all safety labels shown may apply to your lawn mower. 5 SECTION 2: SLOPE GAUGE Use this page as a guide to determine slopes where you may not operate safely. Do not operate your lawn mower on such slopes. FOL DO N DO TTE DL IN E , 15° S EN TI NG A 15 ° SL O PE OR A FENCE POST A CORNER OF A BUILDING A POWER POLE SIGHT AND HOLD THIS LEVEL WITH A VERTICAL TREE R EP RE WARNING Do not mow on inclines with a slope in excess of 15 degrees (a rise of approximately 2-1/2 feet every 10 feet). A riding mower could overturn and cause serious injury. If operating a walk-behind mower on such a slope, it is extremely difficult to maintain your footing and you could slip, resulting in serious injury. Operate RIDING mowers up and down slopes, never across the face of slopes. Operate WALK-BEHIND mowers across the face of slopes, never up and down slopes. 6 SECTION 3: ASSEMBLING YOUR LAWN MOWER IMPORTANT: This unit is shipped without gasoline or oil in the engine. Be certain to service engine with gasoline and oil as instructed in the separate engine manual before operating your mower. Handle Assembly NOTE: Reference to right or left hand side of the mower is observed from the operating position. Wing Nut Removing Unit From Carton • • • • Handle Mounting Bracket Remove staples, break glue on top flaps, or cut tape at carton end and peel along top flap to open carton. Remove loose parts if included with unit (i.e., operator’s manual, oil, etc.) Cut along corners, lay carton down flat, and remove packing material. Roll or slide unit out of carton and check carton thoroughly for loose parts. Figure 2 • Loose Parts in Carton • • • • Grass Bag Grass Bag Adapter Side Discharge Chute Hardware Pack • Disconnecting Spark Plug Wire • Remove the hairpin clips from the outer hole in the weld pins on the handle mounting brackets. Using a pair of pliers, squeeze one leg of the lower handle against the handle mounting bracket. Insert the hairpin clip into the inner hole on the weld pin. Repeat on other side. See Figure 3. After moving the hairpin clip, insert the carriage bolt from hardware pack in the upper hole on the handle mounting bracket and secure with plastic wing nut from the hardware pack. Repeat on other side. Carriage Bolt Lower Handle Before setting up your lawn mower, disconnect the spark plug wire from the spark plug and ground against the engine. See Figure 1. Inner Hole Wing Nut Hairpin Clip Handle Mounting Bracket Spark Plug Wire Spark Plug Figure 3 • Figure 1 Setting Up Your Lawn Mower • • Remove grass bag and other loose parts from unit and set it aside. Lift up and pull back on the upper handle to raise the handle into the operating position. Make certain the lower handle is seated securely into the handle mounting brackets. Tighten the wing nuts on each side of the handle (carriage bolts must be seated properly into the handle). See Figure 2. Fasten the cables to the lower handle with the two cable ties found on the lower handle. Be sure to insert the post on the cable ties into the holes provided on the lower handle. These holes may be found on either the inside or outside of the handles. Pull the cable ties tight and trim off the excess. See Figure 4. Cable Tie Lower Handle NOTE: Your mower is shipped with the handle in the higher height position. If you wish to lower the height of the handle, refer to the Adjustment Section at this time. Figure 4 7 NOTE: Make certain the drive cable is routed around the outside and above the lower handle so it does not interfere with attaching the grass bag. • • Lower Handle The rope guide, which is connected to the support rod, is located on the right side of lower handle. See Figure 5. With the spark plug wire disconnected and grounded, hold the blade control handle against the upper handle, and pull the starter rope out of the engine. Release the blade control handle. Slip the starter rope into the rope guide. Starter Rope Support Rod Rope Guide Figure 5 SECTION 4: KNOW YOUR LAWN MOWER Shift Lever Read this operator’s manual and safety rules before operating your lawn mower. Compare the illustrations in Figure 6 with your lawn mower to familiarize yourself with the location of various controls and adjustments. Save this manual for future reference. The shift lever is located on the drive clutch control housing on the upper handle. This lever is used to select the forward speed of the mower. When changing speed selection, release the drive clutch control. See Figure 6. WARNING: The operation of any lawn mower can result in foreign objects being thrown into the eyes, which can damage your eyes severely. Always wear safety glasses while operating the mower, or while performing any adjustments or repairs on it. NOTE: Move the shift lever only when the engine is running. Changing the shift lever setting with the engine off can cause damage to the mower. Engine Controls See the separate engine manual for the location and function of the controls on the engine. Recoil Starter The recoil starter is attached to the right lower handle. Stand behind the unit and pull the recoil starter to start the unit. See Figure 6. Stopping Engine • Blade Control Handle • The blade control handle is located on the upper handle of the mower. The blade control handle must be depressed in order to operate the unit. Release blade control handle to stop engine and blade. See Figure 6. Release blade control handle to stop the engine and the blade. Disconnect spark plug wire and ground it to the post on the engine. Blade Control Handle WARNING: This blade control mechanism is a safety device. Never attempt to bypass its operations. Shift Lever Cutting Height Adjustment Lever Cutting Height Adjustment Lever Drive Clutch Control The cutting height adjustment lever is located above the left rear wheel. To adjust the cutting height, refer to the Adjustment Section in this manual. See Figure 6. Mulching Plug Recoil Starter Drive Clutch Control The drive clutch control is located on the upper handle. Squeeze the drive control to engage the drive system. Release the clutch control to disengage the drive system. Release the clutch control to slow down when approaching an obstacle, making a turn, or stopping. See Figure 6. Discharge Chute Figure 6 8 SECTION 5: OPERATING YOUR LAWN MOWER Towards Better Mower Performance 1. Pour fresh, clean gasoline into the mower’s gas tank until the tank is full. Do not use gasoline that is more than 30 days old. 2. Make sure to connect the mower’s spark plug wire before trying to start the engine. 3. Add engine oil to the oil fill on the mower engine. Check the dipstick and add more if necessary. Remember that the oil level has to touch the fill line. 4. Locate the primer decal near the primer bulb on the engine, and read its instruction. Using your thumb, press the primer bulb slowly as many times as the decal advises. 5. Hold control handle down and pull rope firmly to start the engine. 6. Set cutting height adjustment lever to middle setting and mow a single pass on your lawn; then adjust to desired height for a closer cut. 7. To mulch insert the mulch plug/cover on the mower. 8. Before storing the lawn mower for the winter, use stabilizer-treated fuel and run the tank dry. 9. Thirty days before start of the new season, check the air filter, spark plug and blade on the lawn mower, and replace if needed. WARNING: Keep hands and feet away from chute area on the cutting deck. The operation of any lawn mower can result in foreign objects being thrown into the eyes, which can result in severe eye damage. Always wear safety glasses or eye shields. • • • • NOTE: For shipping purposes your mower is set with the wheels in a low cutting height position. For best results raise the cutting position until it is determine which height is best for your lawn. See the adjustment section for details. Starting Engine • Gas and Oil Fill-Up • Service the engine with gasoline and oil as instructed in the separate engine manual packed with your mower. Read instructions carefully. • WARNING: Never fill fuel tank indoors with engine running or until the engine has been allowed to cool for at least two minutes after running. • Before Starting Your Mower • • Attach spark plug wire to spark plug. Make certain the metal cap on the end of the spark plug wire is fastened securely over the metal tip on the spark plug. Check for proper drive clutch operation using the NEUTRAL ADJUSTMENT TEST. Prime engine as instructed in the separate engine manual packed with your unit. Your lawn mower is equipped with a constant speed throttle, which is set at full throttle for best performance. Stand behind the mower and squeeze the blade control handle against the upper handle. Grasp recoil starter handle and pull rope out slowly until engine reaches the start of compression cycle (rope will pull slightly harder at this point). Let the rope rewind slowly. Pull rope with a rapid, continuous, full arm stroke. Keeping a firm grip on the starter handle, let the rope return to the starter slowly. Using Your Lawn Mower Be sure that the lawn is clear of stones, sticks, wire, or other objects which could damage the lawn mower or the engine. Such objects could be accidently thrown by the mower in any direction and cause serious personal injury to the operator and others. Neutral Adjustment Test To perform the neutral adjustment test answer the following questions. • Squeeze the drive clutch control and pull the mower backward. Do the rear wheels lock? Is the drive clutch control cable free of kinks or sharp bends? If you answered “yes” to all three questions, your mower passed the test and you can start your mower. If you answered “no” to any of the three questions, you will have to adjust the drive clutch control as instructed in the ADJUSTMENT SECTION. For best results, do not cut wet grass because it tends to stick to the underside of the mower, preventing proper discharge of grass clippings, and could cause With the drive clutch control released, push mower forward and pull it backward. Does it move freely? 9 you to slip and fall. New grass, thick grass, or wet grass may require a narrower cut. NOTE: The chute door has been designed to move the starter rope out of the way of the bag when the chute door is opened. For a healthier lawn, never cut off more than one-third of the total length of the grass. Your lawn should be cut in the fall as long as there is growth. This mower is designed to be operated at full throttle to give you the best cut and do the most effective job of mowing or mulching. Chute Door WARNING: If you strike a foreign object, stop the engine. Remove wire from the spark plug, thoroughly inspect the mower for any damage, and repair the damage before restarting and operating the mower. Extensive vibration of the mower during operation is an indication of damage. The unit should be promptly inspected and repaired. Grass Bag Figure 8 Mulching Attaching Side Discharge Chute For effective mulching, do not cut wet grass because it tends to stick to the underside of the deck, preventing proper mulching of grass clippings. New or thick grass may require a narrower cut. The ground speed should be adjusted to the condition of the lawn. If mowing has been delayed and the grass has been allowed to grow in excess of 4”, mulching is not recommended. Mow using the grass bag to reduce the grass height to 3 1/4” maximum before mulching. • • Remove mulching baffle or grass bag adapter from unit by disconnecting wing nuts. Attach side discharge chute to unit and secure with the three wing nuts. See Figure 9. Attaching The Grass Bag • • Remove three wing nuts holding the mulching baffle or side discharge chute in place and remove from unit. Replace with grass bag adapter, while making sure the front lip of adapter goes under the edge of the deck. Secure with wing nuts previously removed. See Figure 7. Side Discharge Chute Grass Bag Adapter Figure 9 Emptying the Grass Bag • • Wing Nuts • Figure 7 • Lift chute door on the grass bag adapter and slide grass bag onto the adapter. See Figure 8. 10 While holding the grass bag by both the rear handle and the lower handle, lift the grass bag straight up off the adapter. The chute door will move the rope out of the way of the bag. Continue to hold the lower handle and raise the rear of the grass bag up toward your chest. The grass bag will open and the grass clippings will disperse. When replacing the grass bag, be sure the top of the bag rests on the wire support between the handles. SECTION 6: MAKING ADJUSTMENTS WARNING: Do not at any time make any adjustments without first stopping engine and disconnecting spark plug wire. • Cutting Height Adjustment • • Your mower is shipped with the cutting height in the lowest position. The cutting height adjustment lever is located above the left rear wheel. To adjust the cutting height, pull the lever out and away from the mower and then move it forward or backward to select a new cutting height. See Figure 10. Place the hairpin clips in the inner holes in the weld pins and insert the carriage bolts the upper hole on the handle mounting bracket and secure with plastic wing nuts. Reassemble the upper handle to the lower handle. Attach the starter rope as instructed in the Assembly Section. Notch NOTE: For rough or uneven lawns, move the height adjustment lever to a higher position. This will help stop scalping. Lower Handle Cutting Height Adjustment Lever Figure 11 Drive Clutch Control Adjustment Lower The adjustment wheel is located in the drive clutch control handle housing and is used to tighten or loosen the drive belt. You will have to adjust the drive clutch control if any of the following happens: • The mower does not propel itself with the drive clutch engaged. • The mower’s drive wheels hesitate with the drive clutch engaged. To resolve the above problems, rotate the adjustment wheel with your fingers. Clockwise to tighten the cable and counter-clockwise to loosen the cable. See Figure 12. Higher Figure 10 Handle Height Adjustment Bottom View Your mower is shipped with the handle in the higher height position. To lower the height proceed as follows: • • • • • Remove the starter rope from the rope guide. Remove the upper handle by removing the hand knobs and carriage bolts. Lay the upper handle out of the way, being careful not to bend or kink the cables. Remove the hairpin clips from the weld pins on the handle brackets and remove the wing nuts and carriage bolts from the upper hole on the handle mounting bracket. Press out on the legs of the lower handle and remove lower handle from the mower. Turn lower handle around so the notch on the bottom of the lower handle is facing forward. See Figure 11. Reassemble, placing the bottom holes in the handle over the weld pins in the handle mounting bracket. Upper Handle Adjustment Wheel Drive Clutch Control Figure 12 NOTE: For some people the drive clutch control may not be in a comfortable position. You can adjust the handle out by tightening the adjustment wheel. Shift Lever Cable Adjustment Periodic adjustment of the six speed shift cable may be 11 required due to normal wear on the cable. Adjustment is needed if all six speeds do not work. • The adjustable cable bracket is located on the left side of the mower beside the engine. See Figure 14. • • Loosen hex nut which secures the adjustable cable bracket. See Figure 14. Push back on the adjustable cable bracket and tighten hex nut. Adjustable Cable Bracket Start engine and place speed control lever in the sixth speed position. See Figure 13. Hex Nut Bottom View Speed Control Lever Upper Handle PUSH Figure 14 Engine Adjustments Figure 13 • See the separate engine manual packed with your unit for adjustments to the engine. Stop engine and disconnect spark plug wire and ground it against engine. SECTION 7: MAINTAINING YOUR LAWN MOWER General Recommendations 10 0h ou On rs ce as ea so Be n for es tor ag e ou rs 50 h Ev er y Ev er y 25 hu se Ev er y SCHEDULE Af ter ea c MAINTENANCE ho ur s Customer Responsibilities SERVICE DATES PRODUCT Lubricate Wheels Lubricate Blade Control Clean Deck Blade Care Check Oil ENGINE Change Oil Replace Air Filter Clean Engine Check Spark Plug Check Spark Arrester (if any) • • Always observe safety rules when performing any maintenance. The warranty on this lawn mower does not cover items that have been subjected to operator abuse or negligence. To receive full value from the warranty, operator must maintain the lawn mower as instructed in this manual. • • 12 Changing of engine governed speed will void engine warranty. Some adjustments will have to be made periodically to maintain your unit properly. All adjustments in the Making Adjustments section of this manual should be checked at least once each season. • • Periodically check all fasteners and make sure these are tight. Follow the maintenance schedule under Customer Responsibilities to get quality performance from your lawn mower. • Lubrication • WARNING: Always stop engine and disconnect spark plug wire before cleaning, lubricating or doing any kind of service work on the lawn mower. usually indicate that the air cleaner should be serviced. To service the air cleaner, refer to the separate engine manual packed with your unit. The spark plug should be cleaned and the gap reset once a season. Spark plug replacement is recommended at the start of each mowing season. Clean the engine regularly with a cloth or brush. Keep the cooling system (blower housing area) clean to permit proper air circulation which is essential to engine performance and life. Be certain to remove all grass, dirt, and combustible debris from muffler area. Deck Blade Control: Lubricate the pivot points on the blade control handle at least once a season with light oil. The blade control must operate freely in both directions. See Figure 15. The underside of the mower deck should be cleaned after each use to prevent a buildup of grass clippings, leaves, dirt, or other matter. If this debris is allowed to accumulate, it will invite rust and corrosion, and may prevent proper mulching, discharge, or bagging. The deck may be cleaned by tilting the mower and scraping clean with a suitable tool (make certain the spark plug wire is disconnected). Wheels: Lubricate the wheels at least once a season with light oil (or motor oil). If the wheels are removed for any reason, lubricate the surface of the axle bolt and inner surface of the wheel with light oil. See Figure 15. Engine: Follow the separate engine manual packed with you unit for lubrication instructions. IMPORTANT:We do not recommend the use of a pressure washer or garden hose to clean your unit. Cutting Blade Removal, Replacement, and Sharpening • Lubricate • • When removing the cutting blade for sharpening or replacement, protect your hands with a pair of heavy gloves or use a heavy rag to hold the blade. Remove the bolt and the blade bell support which hold the blade and the blade adapter to the engine crankshaft. See Figure 16. Remove the blade and the adapter from the crankshaft. WARNING: Periodically inspect the blade adapter for cracks, especially if you strike a foreign object. Replace when necessary. Figure 15 Blade Adapter Maintenance Blade Bell Support NOTE: When tipping the unit, empty the fuel tank and keep the air cleaner side of engine up. Never tip the mower more than 90 degrees and do not leave the mower tipped for any length of time. Oil can drain into the upper part of the engine causing a starting problem. Hex Bolt Engine Refer to the separate engine manual for all engine maintenance instructions. • • Figure 16 When sharpening the blade, follow the original angle of grind as a guide. It is extremely important that each cutting edge receives an equal amount of grinding to prevent an unbalanced blade. An unbalanced blade will cause excessive vibration when rotating at high Maintain engine oil as instructed in the separate engine manual packed with your unit. Service air cleaner every 25 hours under normal conditions. Poor engine performance and flooding 13 speeds. It may cause damage to the mower, and could break causing personal injury. • The blade can be tested by balancing it on a round shaft screwdriver. Remove metal from the heavy side until it balances evenly. It is recommended that the blade always be removed from the adapter when testing for balance. Before reinstalling the blade and the blade adapter to the unit, lubricate the engine crankshaft and the inner surface of the blade adapter with light oil. • • • • • Cutting Height Adjustment Be sure to install the blade with the side of the blade marked “Bottom” (or with part number) facing the ground when the mower is in the operating position. Slide the blade adapter onto the engine crankshaft. Place the blade on the adapter. Be certain the blade is aligned and seated on the blade adapter flanges. Place blade bell support on blade. Make sure the notches on the blade bell support are aligned with small holes in the blade. Replace hex bolt and tighten to torque: 450 in. lbs. min., 600 in. lbs. max. • • • • • • • Tilt the transmission forward and loosen the idler pulley bolt and lock nut half a turn. See Figure 19. Using a pair of pliers, pull back and rotate belt keeper bracket from the slot on the idler pulley. Slide the belt out from between the belt keeper bracket and the idler pulley. Transmission Pulley Drive Belt Removal and Replacement • Hex Bolt Figure 18 NOTE: To ensure safe operation of your mower, the blade bolt must be checked periodically for correct torque. • Remove the hex bolt from the rear of unit holding the transmission to the mower housing. See Figure 18. Disconnect the spark plug wire and ground it against the engine. Drain the fuel tank or place a piece of plastic beneath the cap to prevent gasoline leakage. Place shift lever in the first position and tip the mower on its side with air filter facing up. Remove the center bolt which secures the blade to the crankshaft followed by blade bell support, blade, and blade adapter. Move the cutting height adjustment to the highest position. Remove the three hex screws holding the baffle to the deck and pivot baffle towards the rear of the mower. See Figure 17. Belt Belt Keeper Bracket Idler Pulley Bracket Transmission Idler Pulley Bolt and Locknut Figure 19 • • Baffle • Figure 17 14 Squeeze the belt together and push it forward, while pressing the control arm inward towards the deck and remove the six speed cable from the slot. See Figure 20. Pivot the control arm down away from the pulley and belt. Lift off the lower pulley assembly and remove the old belt from around the crankshaft. See Figure 20. Six-Speed Cable Slot • Belt Control Arm Pinch both sides of the belt together so that the belt is not in the pulley groove, and the lower pulley can be pushed towards the engine. See Figure 22. Lower Pulley Half Belt Belt Guard Pin Lower Pulley Half Figure 22 Crankshaft • • Pivot the control arm back to its original position and reinstall the six-speed cable into the slot. See Figure 23. Check and make sure the belt is routed inside the pulley halves and the belt guard pin. Six-Speed Cable Slot Belt Figure 20 • • • • • Place the new belt over the transmission pulley. Start the belt in the pulley groove and rotate the pulley until the belt is seated in the transmission pulley. Refer to Figure 20. Place the belt between the idler pulley and the belt keeper bracket. Using pliers, rotate the belt keeper bracket so that it snaps into slot on the idler bracket. Refer to Figure 19. Tighten the idler pulley bolt and lock nut half a turn. Place the belt between the two pulley halves on the crankshaft. Make sure to route the belt inside the belt guard pin. See Figure 21. Control Arm Figure 23 • • • Upper Pulley Half • Tab Belt Reinstall the bolt securing transmission to rear mower housing. Pivot the baffle back to its original position and secure with three hex screws removed earlier. Lightly lubricate the inside of the blade adapter and reinstall the spacer, wave washer, blade adapter assembly, and blade in the correct order. Tighten the hex bolt to secure the blade to torque: 450-600 in. lbs. Storing your Lawn Mower Lower Pulley Half Belt Guard Pin The following steps should be taken to prepare your lawn mower for storage. • Figure 21 Clean and lubricate mower thoroughly as described in the lubrication instructions. IMPORTANT:We do not recommend the use of a pressure washer or garden hose to clean your unit. IMPORTANT: When replacing the belt, do not disassemble the lower pulley assembly. 15 • • • Refer to engine manual for correct engine storage instructions. Coat mower’s cutting blade with chassis grease to prevent rusting. Store mower in a dry, clean area. Do not store next to corrosive materials, such as fertilizer. NOTE: When storing any type of power equipment in a poorly ventilated or metal storage shed, care should be taken to rust-proof the equipment. Using a light oil or silicone, coat the equipment, especially cables and all moving parts. SECTION 8: TROUBLESHOOTING Problem Cause Remedy Engine fails to start 1. 2. 3. 4. 5. 6. Engine runs erratic 1. Spark plug wire loose. 2. Blocked fuel line or stale fuel. 3. 4. 5. 6. Engine overheats Blade control handle disengaged. Spark plug wire disconnected. Fuel tank empty or stale fuel. Blocked fuel line. Faulty spark plug. Engine flooded Vent in gas plugged. Water or dirt in fuel system. Dirty air cleaner. Carburetor out of adjustment. 1. Engine oil level low. 2. Air flow restricted. 3. Carburetor not adjusted properly. 1. 2. 3. 4. 5. 6. Engage blade control handle. Connect wire to spark plug. Fill tank with clean, fresh gasoline. Clean fuel line. Clean, adjust gap, or replace. Wait a few minutes to start engine. 1. Connect and tighten spark plug wire. 2. Clean fuel line; fill tank with clean, fresh gasoline 3. Clear vent. 4. Drain fuel tank. Refill with fresh fuel. 5. Clean air cleaner. 6. Adjust carburetor. 1. Fill crankcase with proper oil. 2. Remove blower housing and clean. 3. Adjust carburetor. Occasional skip (hesitates) 1. Spark plug gap too close. at high speed 1. Adjust gap to .030”. Idles poorly 1. Spark plug fouled, faulty or gap too wide. 2. Carburetor improperly adjusted. 3. Dirty air cleaner. 1. Reset gap to .030” or replace spark plug. 2. Adjust carburetor. 3. Clean air cleaner. Excessive vibration 1. Cutting blade loose or unbalanced. 1. Tighten blade and adapter. Balance blade. 2. Replace blade. 2. Bent cutting blade. Mower will not mulch grass 1. Wet grass. 2. Excessively high grass. 3. Dull blade. Uneven cut 1. Wheels not positioned correctly. 2. Dull blade. Wheels will not propel 1. Belt not installed properly. 2. Debris clogging drive operation. 1. Do not mow when grass is wet; wait until later to cut. 2. Mow once at a high cutting height, then mow again at desired height or make a narrower cutting path. 3. Sharpen or replace blade. 1. Place all four wheels in same height position. 2. Sharpen or replace blade. 1. Check belt for proper pulley installation and movement. 2. Clean out debris with engine off. NOTE: For repairs beyond the minor adjustments listed above, contact your nearest authorized service dealer. 16 Notes 17 Model 979 1 2 3 93 4 15 14 8 5 17 9 7 6 12 23 20 18 13 10 22 19 16 11 35 36 37 38 39 33 21 43 42 44 40 41 45 48 50 56 54 52 57 28 24 32 34 27 49 46 51 55 53 57 59 45 62 63 64 65 47 58 25 66 31 26 33 67 89 61 68 69 70 73 88 71 72 76 77 90 29 91 30 74 75 78 79 81 80 92 82 83 84 85 86 87 18 60 Model 979 Ref. No. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. Part No. 747-0824 731-0904A 16864 731-0620 713-0397 732-0627 731-0924 731-0905A 710-1667A 731-0906 746-0711A 712-0324 746-0883 710-1270 746-1131 749-0439C 720-0241 736-0451 710-1174 726-0240 749-0907A 664-0074 747-0940A 747-0939 747-0937 631-0071 731-1901 732-0842 631-0066 731-1832 731-1833 782-0046B 712-0397 710-0703 746-0939 782-7574A 736-0270 712-0287 710-0167 712-0138 782-7575A 736-0329 756-0625 738-0924 714-0104 736-0286 782-0565 Ref. No. Part Description 48. 49. 50. 51. 52. Control Handle Upper Control Handle 6 Spd. Rack Cable Bracket Control Lever Gear Insert Shift Lever Spring 6 Speed Shift Lever Lower Control Housing C Sunk Tap Screw #10 x .75 Lg Cable Mounting Cap Drive Cable 51.0 Top Lock Nut 1/4-20 Control Housing Oval C-Sunk Screw Control Cable 46” Upper Handle Wing Nut Saddle Washer .320 ID x .830 OD Carriage Bolt 5/16-18 x 2.0 Cable Tie Lower Handle Grassbag Support Rod w/ Rope Guide Pivot Rod Grassbag Frame Grassbag Cover Trail Shield Trail Shield Wire Chute Assembly Side Discharge Chute Mulch Cover Deck 21” Wing Nut Carriage Bolt 1/4-20 x .75 6 Speed Cable Cable Adjustment Bracket Bell Washer .265 ID x .75 OD Hex Nut 1/4-20 Carriage Screw 1/4-20 x .50 Hex Nut 1/4-28 Cable Mounting Bracket Lock Washer 1/4 Roller Cable Shoulder Screw .375 ID x 1/4-14 Cotter Pin Bowed Washer Single Lever Control Arm 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 78. 79. 80. 81. 82. 83. 84. 85. 86. 87. 88. 89. 90. 91. 92. 93. 19 Part No. 734-1981 712-0414 16855 10622B 748-0381 748-0188B 738-0137A 748-0318 736-0270 710-0751 731-1426 738-0102 736-0504 734-1978 736-0105 710-1348 710-0896 710-0654A 611-0064 736-0204 710-0703 710-1242 741-0492A 710-1241 731-1829 754-0460 656-0613 750-1071 750-1070 782-7597 710-0654A 782-7596 732-0807 711-1114 736-0526 731-1828 710-0653 753-0609 742-0741 736-0524A 710-1257 731-1874 732-0819 726-0111 747-0965 731-1713B 720-0294 Part Description Wheel 9 x 2 Top Lock Tab Weld Nut 1/4-20 Ratchet Pawl Plate Plastic Spring Ratchet Pawl RH Pawl LH Shld Screw .340 ID x .285 OD Wheel Rachet Bell Washer .265 ID x .75 OD Hex Cap Screw 1/4-20 x .620 Hubcap Shoulder Screw .498 x 1.445 Wave Washer .510 ID x .750 OD Wheel 8 x 2 Spring Washer .401 ID x .870 OD Screw 1/4-14 x .500 Screw 1/4-14 x .625 Hex Washer Screw 3/8-16 x 1.0 Front Axle Assembly Flat Washer .344 ID x .62 OD Carriage Screw 1/4-20 x .75 Torx Screw Block Bushing Hex Washer Screw Front Axle Cover Belt 3/8 x 39.24 Pulley Assembly Sleeve Spacer .88 ID x 1.13 OD Sleeve Spacer .88 ID x 1.00 OD Pivot Bracket Screw 3/8-18 x 1.0 Control Arm Torsion Spring Pivot Shaft Wave Washer 1.38 ID x .88 OD Baffle Screw 1/4-20 x 3.75 Blade Adapter Kit 21” Mulching Blade Blade Bell Support Hex Bolt 3/8-24 x 2.5 Chute Door Torsion Spring Push Cap Pivot Rod Discharge Chute Grip Model 979 1 2 15 16 8 3 17 28 27 11 4 26 5 6 25 9 24 7 10 18 12 21 14 29 7 13 23 14 22 30 19 7 31 30 20 33 32 34 35 36 37 38 40 39 43 41 42 44 45 46 48 47 49 51 58 52 50 53 56 54 55 57 20 Model 979 Ref. No. Part No. Ref. No. Part Description Part No. Part Description 1. 720-0223 Grip 30. 736-0425 Bell Washer .325 ID x .930 OD 2. 732-0803A Spring Lever 31. 756-0656 Pulley 3. 738-0529 Shoulder Nut .825 x .165 Lg. 32. 736-3084 Flat Washer .510 ID x 1.120 OD 4. 710-0751 Cap Screw 1/4-20 x .620 33. 712-0896 Hex Jam Nut 1/4-28 5. 736-0270 Bell Washer .285 ID x .75 OD 34. 782-7598 Belt Keeper 6. 748-0318 Wheel Rachet 35. 741-0600 Bearing 7. 736-0369 Flat Washer .508 ID x 1.0 OD 36. 732-0849A Extension Spring 8. 682-0531 Pivot Arm Assembly 37. 750-1050 Flange Spacer 9. 750-0515 Spacer .510 ID x .70 OD 38. 682-0027A Idler Bracket Assembly 10. 741-0978 Sleeve Bearing .504 ID x .830 OD 39. 710-0299 Hex Cap Screw 1/4-28 x 1.0 11. 750-1056 Shoulder 40. 741-0682A Bearing Sleeve 12. 710-0653 Tap Screw 1/4-20 x .375 41. 736-0570 Flat Washer .885 ID x 1.45 OD 13. 682-7528 Chain Cover Assembly 42. 721-0329 Oil Seal 14. 741-0324 Flange Bearing .506 ID x .590 Lg 43. 721-0325 Plug 15. 682-7526 Transmission Axle Assembly 44. 618-0253 Upper Housing Assembly 16. 618-0263A Transmission Assembly 45. 782-7601A Cable Bracket 17. 710-0604A Hex Screw 5/16-18 46. 741-0690 Bearing 18. 713-0453 Chain 47. 736-0616 Thrust Washer .504 ID x .70 OD 19. 638-0012 Rear Axle Assembly 48. 782-7595 Pivot Bracket 20. 741-0522 Flange Bearing .506 ID x .715 Lg 49. 741-0324 Flange Bearing 21. 732-0832 Torsion Spring 50. 711-1168 Output Shaft 6T 22. 750-0151 Spacer .550 ID x .750 OD 51. 717-1469 Gear 34T 23. 710-1315 Screw 3/8-16 x .25 52. 741-0674 Bearing 24. 711-0835 Clevis Pin .50 Dia x 4.82 Lg. 53. 717-1487 Pinion Shaft 10T 25. 750-0807 Spacer .385 ID x .624 OD 54. 736-0314 Thrust Washer 3/8 x .70 26. 782-0568 Hgt Adjustment Spring Bracket 55. 736-0569 Thrust Washer .388 x .625 27. 710-1652 Screw 1/4-14 x .825 56. 618-0252 Lower Housing Assembly 28. 714-0474 Cotter Pin 57. 710-0642 Hex Screw 1/2-20 x .75 29. 712-3025 Hex Jam Nut 5/16-24 58. 611-0066 Shaft Assembly 21 22 23 MANUFACTURER’S LIMITED WARRANTY FOR: The limited warranty set forth below is given by MTD PRODUCTS INC (“MTD”) with respect to new merchandise purchased and used in the United States, its possessions and territories. MTD warrants this product against defects in material and workmanship for a period of two (2) years commencing on the date of original purchase and will, at its option, repair or replace, free of charge, any part found to be defective in material or workmanship. This limited warranty shall only apply if this product has been operated and maintained in accordance with the Operator’s Manual furnished with the product, and has not been subject to misuse, abuse, commercial use, neglect, accident, improper maintenance, alteration, vandalism, theft, fire, water or damage because of other peril or natural disaster. Damage resulting from the installation or use of any accessory or attachment not approved by MTD Products Inc. for use with the product(s) covered by this manual will void your warranty as to any resulting damages. Normal wear parts or components thereof are subject to separate terms as follows: All normal wear part or component failures will be covered on the product for a period of 90 days regardless of cause. After 90 days, but within the two year period, normal wear part failures will be covered ONLY IF caused by defects in material or workmanship of OTHER component parts. Normal wear parts and components include, but are not limited to, belts, blades, blade adapters, grass bags, rider deck wheels, seats, snow thrower skid shoes, shave plates and tires. Batteries are covered by a 90day limited replacement warranty. HOW TO OBTAIN SERVICE: Warranty service is available, WITH PROOF OF PURCHASE THROUGH YOUR LOCAL AUTHORIZED SERVICE DEALER. To locate the dealer in your area, please check for a listing in the Yellow Pages or contact the Customer Service Department of MTD PRODUCTS INC by calling 1-800-800-7310 or writing to P.O. Box 368022, Cleveland, Ohio 44136-9722. This limited warranty does not provide coverage in the following cases: a. The engine or component parts thereof. These items carry a separate manufacturer’s warranty. Please refer to the applicable manufacturer’s warranty on these items. b. Log splitter pumps, valves and cylinders have a separate one year warranty. c. Routine maintenance items such as lubricants, filters, blade sharpening and tune-ups, or adjustments such as brake adjustments, clutch adjustments or deck adjustments; and normal deterioration of the exterior finish due to use or exposure. d. MTD does not extend any warranty for products sold or exported outside of the United States of America, its possessions and territories, except those sold through MTD’s authorized channels of export distribution. No implied warranty, including any implied warranty of merchantability or fitness for a particular purpose, applies after the applicable period of express written warranty above as to the parts as identified. No other express warranty or guaranty, whether written or oral, except as mentioned above, given by any person or entity, including a dealer or retailer, with respect to any product shall bind MTD. During the period of the Warranty, the exclusive remedy is repair or replacement of the product as set forth above. (Some states do not allow limitations on how long an implied warranty lasts, so the above limitation may not apply to you.) The provisions as set forth in this Warranty provide the sole and exclusive remedy arising from the sales. MTD shall not be liable for incidental or consequential loss or damages including, without limitation, expenses incurred for substitute or replacement lawn care services, for transportation or for related expenses, or for rental expenses to temporarily replace a warranted product. (Some states do not allow the exclusion or limitation of incidental or consequential damages, so the above exclusion or limitation may not apply to you.) In no event shall recovery of any kind be greater than the amount of the purchase price of the product sold. Alteration of the safety features of the product shall void this Warranty. You assume the risk and liability for loss, damage, or injury to you and your property and/or to others and their property arising out of the use or misuse or inability to use the product. This limited warranty shall not extend to anyone other than the original purchaser, original lessee or the person for whom it was purchased as a gift. How State Law Relates to this Warranty: This limited warranty gives you specific legal rights, and you may also have other rights which vary from state to state.