Husqvarna 345 and 343 brush cutter service and repair manual

Workshop manual 343R 345RX 343F 345FX 345FXT English

1 Workshop Manual Brushcutter, Trimmer Model 343R, 345RX, 343F, 345FX, 345FXT Contents General recommendations ___________________ 2 1. Starter __________________________________ 3 2. Electrical system _________________________ 7 3. Fuel system _____________________________ 15 4. Centrifugal clutch ________________________ 31 5. Angle gear ______________________________ 37 6. Cylinder and piston ______________________ 41 7. Crankshaft and crankcase_________________ 51 8. Tools ___________________________________ 59 © Copyright Husqvarna AB, Sweden 2003

2 502 51 03-01 General recommendations ! ! ! ! ! ! Remember: Never start the engine without the clutch and clutch drum mounted. Do not grasp hot elements such as the muffler or the clutch before they have cooled sufficiently to avoid burn injuries. Avoid getting petrol on you skin or in your mouth. Use protective cream on your hands. This lowers the risk of infection and makes dirt easier to wash off. Long-term contact with engine oil can be damaging to your health. Never run the engine indoors. The engine exhaust is poisonous! Wipe up any spilled oil from the floor immediately in order to avoid injuries from slipping. Do not use tools that are worn or fit poorly on nuts and bolts and so on. + Always work on a clean work surface. + Always work in a logical manner in order to be sure that all components are correctly attached and that nuts and bolts are tightened. + Use special tools where recommended in order to work correctly. Fire risk Handle petrol with respect, since it is highly flammable. Do not smoke and ensure that there are no open flames or sparks in the vicinity. Make sure that there is a functioning fire extinguisher in the vicinity. Do not try to extinguish a petrol fire with water. Poisonous fumes When using cleaning fluids, read the instructions carefully. Make sure that ventilation is good when handling petrol, trichlo- roethylene and other highly volatile liquids. The engine exhaust is poisonous. Test run the engine only if ventilation is good. Preferably outside. Special tools Certain tasks in this handbook require the use of special tools. In sections where this is applicable, an image of the tool with an ordering number is provided. We recommend using special tools in order to avoid personal injury and to eliminate expensive damage to the components in question. Sealing faces and gaskets Make sure that all sealing faces are clean and free from old gasket remnants. Use a tool that will not damage the sealing face when it is cleaned. Any scratches and irregularities should be removed with a fine, float-cut file. Sealing rings Always change a sealing ring once it has been dismounted. The sensitive sealing lips can be easily damaged with poor sealing ability as a result. The surfaces that the seal is to tighten against must also be completely free from damage. Lubricate the sealing lip with grease before it is attached and make sure that it is not damaged by such things as the collars and splines on an axle. Use tape or a conical bushing as protection. It is important that the sealing ring is turned correctly in order for it to function as intended. WARNING! Risk of personal injury if the instructions are not followed. NOTE! Material damage may occur if the instructions are not followed. !

3 1 1. Contents Dismantling _________________________________ 4 Assembly __________________________________ 5 Replacing the drive dogs ______________________ 6 Starter

4 1 502 50 18-01 Starter WARNING! Protective glasses should be worn when working on the starter to avoid injury to the eyes if, for some reason, the return spring should fly out. ! Remove the bolt in the centre of the starter pulley and remove the starter pulley. Remove the bolt in the centre of the starter pulley. Lift the starter pulley carefully from the starter cover. Loosen the spring tension. Loosen the spring tension. Pull out the starter cord about 30 cm. Brake the starter pulley with your thumb and lift the cord as illustrated. Let the starter pulley rotate backwards slowly. Dismantling Remove the starter from the engine. Dismantling Remove the 4 bolts and lift off the starter. The cylinder cover does not need to be loosened or detached.

5 1 ! Starter Assembly Clean requisite parts and assemble in the reverse order as set out for dismantling. Assembly Clean all components before assembly: Change return springs, starter pulley and starter cord as needed. NOTE! Be careful when opening the packaging with the return spring so that the spring does not fly out. Attach the spring cassette. Attach the starter pulley. Attach the new starter cord. Attach the spring cassette and tighten the two bolts (A). Lubricate the bearing journal with a little grease and attach the starter pulley. Place the washer in place and tighten the bolt. Attach the new starter cord. Push it in to the starter pulley’s track as illustrated and then out through the cord guide in the starter cover. Make sure that the knot at the end of the cord is as small as possible! NOTE! New starter cords can be attached without dismantling the starter! Anchor the cord in the starter handle. Thread the cord through the starter handle and anchor it with a knot. Fold down the free end and pull the knot well into the handle. Remove the spring cassette. Remove the two bolts holding the spring cassette and remove the cassette for replacement if necessary. WARNING! Wear protective glasses. The return spring can fly out and cause personal injury if improperly handled.

6 1 Starter Replacing the drive dogs See chapter 2 Ignition system. Replacing the drive dogs See chapter 2 Ignition system. Tighten the return spring. Check the spring tension. Tighten the return spring. Lift up the starter cord when the return spring is completely loose and the cord pulled out completely. Then turn the starter pulley anti- clockwise 7 revolutions. Check the spring tension. With the cord completely pulled out the cord pulley should be able to be turned at least another half revolution. Mount the starter onto the engine. Mount the starter onto the engine. Pull out the starter cord a little. Place the starter in position and release the starter cord at the same time. Check that the ignition cable is not trapped (see arrow). Check that the drive dogs grip the starter pulley in the correct way. Tighten the bolts.

7 2 . 2 Electrical system Contents Checking the ignition spark ____________________ 8 Replacing the spark plug cover ________________ 10 Dismantling ________________________________ 11 Drive dogs _________________________________ 12 Assembly _________________________________ 12 Heated handles_____________________________ 12

8 2 502 71 13-01 502 51 91-01 Electrical system The engine is equipped with an electronic ignition system completely without moving parts. Conse- quently, a faulty component cannot be repaired, but must be replaced by a new component. The spark in an electronic ignition system has a very short burn time and can therefore be interpreted as weak and can be difficult to see while troubleshooting. Checking the ignition spark Clean the electrodes and check the electrode gap. Checking the ignition spark Remove the spark plug and clean it from soot deposits with the help of a steel brush. Check the electrode gap. It should be 0.5 mm. Adjust the gap as needed to the correct value with the side electrode. If the electrodes are worn more than 50% the spark plug should be changed. If the electrodes are worn more than 50% the spark plug should be changed. Too large a spark gap entails a great deal of stress on the ignition module and risk for short-circuiting. Check if a spark occurs when attempt- ing to start. Test with test spark plug no. 502 71 13- 01 if no spark is seen. Also check that the stop switch is in the start position. Earth the spark plug on the cylinder and pull sharply on the start handle. A spark should be seen between the electrodes. If no spark is seen test with test spark plug no. 502 71 13-01. If a spark then occurs, the spark plug is faulty. Try a new spark plug.

Husqvarna 345 and 343 brush cutter service and repair manual

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