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340, 345, 350
346XP, 351
Workshop manual
101 90 26-26

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Troubleshooting

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   Summary of Contents for Husqvarna 340

  • Page 1

    340, 345, 350 346XP, 351 Workshop manual 101 90 26-26...

  • Page 2: Table Of Contents

    Workshop manual Husqvarna 340, 345, 346XP/G, 350, 351 /G Contents Introduction ............2 Safety regulations ..........3 General instructions ........... 3 Special instructions ..........3 Special tools ............4 Technical data ............6 Construction and function ........8 Carburettor ............8 Troubleshooting ..........

  • Page 3: Introduction

    Introduction Arrangement of the manual Troubleshooting This workshop manual can be used in two different These pages describe the most common faults that ways. affect a chainsaw. They are divided into four different groups with the most likely faults de- •...

  • Page 4: Safety Regulations

    Husqvarna, could mean that the saw no longer meets these safety requirements and the Poor chain lubrication can result in failure of the person who carried out the work may be held chain, which could cause serious or fatal injury.

  • Page 5: Special Tools

    Special tools – English...

  • Page 6

    Special tools Item Description Used for Order no. Clutch tool Centrifugal clutch 502 54 16-01 Piston stop Locking crankshaft 502 54 15-01 Stop plate Locating intake gaiter 502 54 17-01 19 a Fuel filter hook Withdrawing the fuel filter 502 50 83-01 19 b Allen key For M5 bolts...

  • Page 7: Technical Data

    Technical data Displacement Cylinder bore Stroke Max power/speed /cubic inches Ø mm/Ø inches mm/inches kW/hp/rpm 340: 40.8 / 2.48 40.0 / 1.60" 32.5 / 1.28" 2.0/ 2.7 /9,000 345: 45.0 / 2.73 42.0 / 1.65" 32.5 / 1.28" 2.2/ 3.0 /9,000 346XP/G: 45.0 / 2.73...

  • Page 8

    Technical data Idling speed Engagement speed Max. speed Spark plug 340: 2,700 3,800 12,500 Bosch RCJ 7Y, NGK BPMR 7A 345: 2,700 3,800 12,500 Bosch RCJ 7Y, NGK BPMR 7A 346XP/G: 2,700 3,800 14,700 Bosch RCJ 7Y, NGK BPMR 7A...

  • Page 9: Construction And Function

    Construction and function Carburettor The carburettor consists of three sub-systems: • The pump unit (C) pumps fuel from the tank to the metering system inside the carburettor. One side of the pump diaphragm is connected to the crankcase and pulses as a result of pressure changes in the crankcase.

  • Page 10

    Construction and function In idling mode the throttle valve (F) is closed. Air is sucked through an aperture in the throttle valve and a small amount of fuel is supplied through the In full throttle mode both valves are open and fuel diffuser jet (E).

  • Page 11: Troubleshooting

    Troubleshooting The various faults that can affect a chainsaw are divided into four groups. In each group the likely symp- toms are given on the left and possible causes are listed on the right. The most likely faults are given first, and so on.

  • Page 12: Troubleshooting Methods

    Troubleshooting High rpm Acceleration and retardation Adjust H screw Will not run Does not Adjust L screw Blocked air filter at full throttle accelerate Adjust H screw Blocked fuel tank vent Blocked air filter Blocked fuel filter Blocked fuel tank vent Fuel line blocked Blocked fuel filter Loose or damaged fuel hose...

  • Page 13: Repair Instructions

    Repair instructions Chain brake – dismantling WARNING! Make sure the spring does not fly out and cause injury. Wear eye protection. Unscrew the bolts and remove the clutch cover. Disengage the chain brake before removing the Remove the screws that hold the cover over the clutch cover.

  • Page 14

    Repair instructions Chain brake – reassembly Bolt the elbow joint to the brake band and tighten to a torque of 1–1.5 Nm. Fit the clutch cover in place and press the upper/ Locate the elbow joint and connected brake band front corner while pushing the kickback guard in their recesses in the clutch cover.

  • Page 15: Silencer

    Repair instructions Silencer – removal Silencer – refitting If the saw is equipped with a spark arrestor mesh WARNING! this should be fitted first. Do not touch the silencer until it has cooled down, otherwise you may burn yourself. Fit the cooling plate, gasket and silencer onto the cylinder.

  • Page 16: Stop Switch

    Repair instructions Stop switch – removal Remove the cylinder cover. Push together the plastic clips on the stop switch. Pull out the switch. Remove the air filter by rotating it anti-clockwise. Disconnect both leads from the stop plate using pliers. Cleaning and inspection Clean the mating surfaces and check the resist- ance as follows:...

  • Page 17: Choke Control

    Repair instructions Stop switch – refitting Reconnect the leads to the stop plate. Refit the air filter by rotating it clockwise. Carefully press the new stop switch into place. Refit the stop plate. Push the stop plate into the front slot first and lift the rear edge of the plate into Fit the cylinder cover.

  • Page 18: Throttle Trigger

    Repair instructions Throttle lock/throttle trigger – removal Cleaning and inspection • Clean the parts and check that the locking mechanism is not worn. • Lubricate the throttle lock with oil. • The throttle trigger can be pinned if the locking mechanism is worn.

  • Page 19: Hand Grip Heater

    Repair instructions Hand grip heater on models 351G and Generator – troubleshooting 346XPG – removal Remove the cylinder cover and free the switch from No heating or heating only in front hand grip the front hand grip using a screwdriver. Connect a multimeter between the cylinder and the black lead underneath the cover on the front hand grip.

  • Page 20

    Repair instructions Hand grip heater on models 351G and Remove the air filter, throttle pushrod, rubber gaiter 346XPG – refitting and carburettor (see page 31). Feed the leads into the rear hand grip and insert the heater element in the hand grip. Screw in the Remove the bolt from the plate at the base of the two bolts through the right side of the hand grip to carburettor to release the lead for the heater...

  • Page 21: Starter Assembly

    Repair instructions Starter assembly – removal WARNING! If the recoil spring is still under tension when the pulley is re- moved it can fly out and cause in- jury. Wear eye protection. Remove the bolt from the centre of the pulley and lift off the pulley.

  • Page 22: Starter Cord

    Repair instructions Replacing a broken or worn starter cord Tensioning the recoil spring Before replacing a worn starter cord the tension in Fasten the starter cord in the notch in the pulley the recoil spring must be released. Pull the starter rim and wind the pulley about 2 turns clockwise.

  • Page 23: Ignition Module - Testing

    Repair instructions Replacing a worn recoil spring Starter assembly – refitting WARNING! Make sure the recoil spring does not fly out and cause injury. Wear eye protection. Remove the bolt from the centre of the pulley and lift off the pulley and spring. Remove the broken recoil spring.

  • Page 24: Ignition Module And Flywheel

    Repair instructions Ignition module/flywheel – removal Loosen the flywheel nut and unscrew it until it is flush with the end of the shaft. Raise the washer to Undo the cylinder cover and remove it. Undo the check that the flywheel nut is in the right position. four bolts on the starter assembly and lift it off.

  • Page 25: Generator

    Repair instructions Cleaning and inspection Feed the lead from the new generator through the • Clean all parts, especially the tapers on the hole to the connection on the front hand grip, flywheel and shaft. connect both leads and clip the lead to the fuel tank. •...

  • Page 26

    Repair instructions Ignition module and flywheel – refitting Connect the blue lead to the ignition module. Place the flywheel on the shaft. Turn the flywheel so Fit the cable guide and press the leads into position. that the key lines up with the keyway in the shaft. Fit the spark plug and tighten to a torque of 15 Nm.

  • Page 27: Centrifugal Clutch

    Repair instructions Centrifugal clutch – removal Unbolt the clutch using tool 502 54 16-01 and a number 19 socket. Turn the clutch clockwise to remove it. Remove the clutch cover, cylinder cover, guide bar Remove the clutch shoes and hub. and chain.

  • Page 28

    Repair instructions Inspection and cleaning • Check the thickness of the clutch shoes by using vernier callipers to measure the diameter of the clutch. If the diameter is less than 65 mm the clutch assembly must be replaced. Fit the clutch on the hub and bolt it onto the crank- shaft using tool 502 54 16-01 and a number 19 •...

  • Page 29: Oil Pump

    Repair instructions Oil pump – removal Empty the oil tank. Unbolt the clutch clockwise using tool 502 54 16-01. Remove the clutch cover, cylinder cover, guide bar and chain. The chain brake must be disengaged first. Loosen and remove the clutch drum (A), needle bearing (B) and pump drive wheel (C).

  • Page 30

    Repair instructions Cleaning and inspection • Clean all the parts and check that they are in good condition. • Lubricate all moving parts with chain oil. Adjustable oil pump – reassembly 351/346 Unbolt the oil pump and lift it out. Adjustable oil pump –...

  • Page 31

    Adjustable oil pump – adjustment Use a screwdriver or adjustable spanner to turn the The fixed oil pump on models 340 and 345 is adjuster screw on the pump. Turning the screw assembled with a pin. clockwise decreases the oil flow and turning it anti- clockwise increases the oil flow.

  • Page 32: Carburettor

    Repair instructions Carburettor – removal Remove the cylinder cover and air filter. Disconnect the leads from the stop switch. NOTE! Do not use knurled pliers to disconnect or reconnect the fuel hose. This could dam- age the hose and lead to leakage or frac- ture.

  • Page 33

    Repair instructions Carburettor – dismantling Prise out the carburettor from its rubber mountings using a small screwdriver. Lift out the carburettor. The item numbers in the diagram refer to steps 1–7 below. Remove the cover from the metering unit and carefully remove the metering diaphragm and gasket.

  • Page 34

    Repair instructions Cleaning and inspection The item numbers in the diagram refer to steps 1–7 below. Clean all the carburettor components in petrol. Use an airline to dry off the petrol from all components. Blow through all the channels in the carburettor If the throttle and choke butterflies and their body and check that they are not blocked.

  • Page 35: Carburettor - Pressure Testing

    Repair instructions Carburettor – pressure testing Carburettor – refitting Pressure testing should be carried out with the carburettor fully assembled. Testing should always NOTE! be carried out after the carburettor has been repaired, but can also be performed for trouble- Cleanliness is very important when reas- shooting before dismantling.

  • Page 36

    Repair instructions Fit the throttle lock by pressing the spring back and pressing the throttle lock forwards into position. Then press the throttle lock to the left and down- wards at the same time. Repeat this procedure, this time pressing the throttle lock to the right. When you have heard two clicks the throttle lock is correctly positioned.

  • Page 37: Carburettor - Adjustment

    Repair instructions Carburettor – adjustment Basic settings and running in For instructions on adjusting the EPA carburettor During testing at the factory the carburettor is see appendix A. adjusted to the basic factory settings. The factory settings are H = 1 turn and L = 1 Adjusting the carburettor involves adjusting the turn.

  • Page 38

    Repair instructions Basic requirements • Run the saw again at full throttle for about 10 seconds and listen to the difference in the engine • Before making any adjustments the air filter note. Repeat this procedure again with the H should be clean and the cylinder cover should screw screwed out another 1/4 turn.

  • Page 39: Fuel Tank

    Repair instructions Fuel tank – removal WARNING! The fuel used in chainsaws is harmful if inhaled, may cause skin irritation and is highly flam- mable. Empty the fuel tank. Remove the following: cylinder cover Unbolt the stop plate and vibration damping spring air filter from the flywheel side of the saw.

  • Page 40: Fuel Hose

    Repair instructions Fuel tank – refitting Insert the fuel hose into the carburettor chamber. Refit the fuel tank. Connect the fuel hose to the carburettor. Bolt on the stop plate and spring assembly, Fit the following: making sure that the side support is on the bolt when the stop plate is tightened.

  • Page 41: Piston And Cylinder

    Repair instructions Piston and cylinder – removal NOTE! Remove the cylinder cover, carburettor (see page Take care to prevent dirt or foreign parti- 31), silencer and spark plug. cles getting into the crankcase. Undo the four cylinder bolts and lift the cylinder off carefully.

  • Page 42: Decompression Valve - Pressure Testing

    • The needle roller bearing is undamaged. • The inlet manifold is undamaged. • Pressure test the decompression valve. • Also refer to Husqvarna’s Analysis guide for piston failures, art. no. 106 31 63. Decompression valve – pressure testing If replacing the cylinder: Unscrew the decompression valve.

  • Page 43

    Repair instructions Piston and cylinder – refitting NOTE! It is very important that there are no leaks in the inlet system, otherwise the engine may seize. Press the insulating plate 503 86 62-01 onto the Lubricate the little end bearing with two-stroke oil cylinder.

  • Page 44: Cylinder - Pressure Testing

    Repair instructions Cylinder – pressure testing Fit the cylinder bolts, tightening them in diagonal pairs to a torque of 8–10 Nm. Pressure test the cylinder. • Loosen the carburettor bolts so that the carbu- Fit the spark plug and tighten to a torque of 15 Nm. rettor can be moved back about 4 mm.

  • Page 45: Crankcase And Crankshaft

    • The sealing surfaces of the crankcase seals on the crankshaft are not worn and the rubber has not hardened. Lift out the crankshaft. • That the crankcase does not show signs of cracking. • See also Husqvarna’s Analysis guide for faults and causes. – English...

  • Page 46

    25 cylinder cover clutch cover guide bar and chain Apply silicone rubber 503 26 70-01 to the surfaces of the crankcase that mate with the bearing hous- ing (350), lower cylinder face (340/345). English –...

  • Page 47: Crankshaft Bearings

    Repair instructions Crankcase and crankshaft on 346XP/G and 351/G – dismantling Remove the following: guide bar and chain clutch cover cylinder cover starter assembly page 20 ignition system page 23 generator page 24 centrifugal clutch page 26 oil pump page 28 bark rest chain tensioner throttle pushrod...

  • Page 48

    Repair instructions Crankcase and crankshaft on 346XP/G and 351/G – reassembly Fit and tighten the six crankcase bolts to a torque of 8–10 Nm. Check that the crankshaft rotates freely. Hold the clutch side of the crankcase in a vice. Pull Refit the following parts: the crankshaft into its bearing using assembly tools bark rest...

  • Page 49: Repairing Damaged Threads

    Repair instructions Replacing the fuel filter Repairing damaged threads A repair kit, 503 27 33-01, is available for repairing damaged threads. NOTE! Do not use knurled pliers to disconnect or First drill out the hole using: reconnect the fuel hose. This could damage the hose and lead to leakage or 6.1 mm drill bit for magnesium crankcase fracture.

  • Page 50: Appendix A, Carburettor - Epa Models

    Appendix A Carburettor – EPA models 6. Adjust the H-needle to a top speed of "B" rpm. Model 340 B= 12 300 Basic adjustment for EPA carburettors Model 345 B= 12 700 After replacing the carburettor or high speed and/or...

This manual also for:

345, 350, 351, 351 g, 346 xp, 346 xpg

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