HUSQVARNA CHAINSAW 340 345 346XP Full Service & Repair Manual

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

English – 1 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 .................................................. 10 Repair instructions ............................................. 12 Chain brake ...................................................... 12 Silencer ............................................................ 14 Chain catcher ................................................... 14 Stop switch ....................................................... 15 Stop switch – resistance measurement ........... 15 Choke control ................................................... 16 Throttle trigger .................................................. 17 Hand grip heater .............................................. 18 Starter assembly .............................................. 20 Starter cord ...................................................... 21 Recoil spring .................................................... 21 Ignition module – testing .................................. 22 Ignition module and flywheel ............................ 23 Generator ......................................................... 24 Centrifugal clutch ............................................. 26 Oil pump ........................................................... 28 Carburettor ....................................................... 31 Carburettor – pressure testing ......................... 34 Carburettor – adjustment ................................. 36 Fuel tank .......................................................... 38 Fuel hose ......................................................... 39 Piston and cylinder ........................................... 40 Decompression valve – pressure testing ......... 41 Cylinder – pressure testing .............................. 43 Crankcase and crankshaft ............................... 44 Crankshaft bearings ......................................... 46 Repairing damaged threads ............................. 48 Guide bar bolts ................................................. 48 Fuel filter .......................................................... 48 Appendix A, Carburettor – EPA models ........... 49

2 – English Arrangement of the manual This workshop manual can be used in two different ways. • To repair a specific sub-assembly on a chainsaw. • To dismantle and reassemble a complete chainsaw. Repairing a specific sub-assembly If a specific sub-assembly on the chainsaw needs to be repaired: 1. Look up the page referring to the relevant sub- assembly. 2. Follow the instructions under the headings: Removal/Dismantling Cleaning and inspection Refitting/Reassembly Dismantling and reassembling the entire chainsaw If the entire chainsaw is to be dismantled, follow the instructions under the heading “Removal/ Dismantling”. Work through the manual and follow the instructions given in each section under the heading “Removal/Dismantling”. Then follow all the “Cleaning and inspection” instructions in each section. Working from the back of the manual, follow all the instructions under the headings “Refitting/ Reassembly” in reverse order. Each of the sections covering removal/dismantling and refitting/reassembly include the relevant lubrication instructions and bolt torques for each stage of repair. Construction and function This chapter gives a simple description of the chainsaw carburettor and its various parts. Introduction Troubleshooting These pages describe the most common faults that affect a chainsaw. They are divided into four different groups with the most likely faults described first. Repair instructions The section that describes how to repair the chainsaw consists of detailed, step-by-step instructions. It explains in detail the special tools, lubri- cants and bolt torques that are needed when working on each component. This workshop manual covers the following chainsaw models: 340 345 350 351 351 G 346 XP 346 XPG

English – 3 General instructions This workshop manual gives detailed instructions on how to troubleshoot, repair and test a chainsaw. This section also describes the various safety precautions that should be taken when carrying out repairs. The workshop manual has been written for person- nel who are assumed to have general experience of repairing and servicing chainsaws. Workshops where chainsaws are repaired must be equipped with safety equipment that meets local regulations. No-one should carry out repairs on a chainsaw until they have read and understood the contents of this workshop manual. Chainsaws are type-approved to meet the relevant safety legislation, but this only applies when the saw is fitted with the cutting equipment specified in the user’s manual. The fitting of any other equipment, or of accessories or parts that are not approved by Husqvarna, could mean that the saw no longer meets these safety requirements and the person who carried out the work may be held responsible for its non-conformance. In this workshop manual the following boxes indicate where caution should be taken. Special instructions The fuel that is used in a chainsaw poses the following hazards: • The fuel and its fumes are toxic. • May cause irritation to skin or eyes. • May cause breathing difficulties. • Highly flammable. When using compressed air the air jet should never be pointed at the body. Air can be forced into the bloodstream and cause fatal injury. Wear ear protection when testing saws. After testing a saw do not touch the silencer until it has cooled down. The silencer gets very hot and you may burn yourself. Wear protective gloves when working on the silencer. The guide bar, chain and clutch cover (chain brake) must be fitted before the saw is started. If not, the clutch may come loose and cause injury. Poor chain lubrication can result in failure of the chain, which could cause serious or fatal injury. Take care to ensure that the spring inside the starter assembly does not fly out and cause injury. Wear eye protection. If the spring is under com- pression when the pulley is removed it could fly out and cause injury. Before removing the tensioning spring from the chain brake, ensure that the brake is in the on position, otherwise the spring may fly out and cause injury. After repair, the chain brake must be checked as described on page 13. Always consider the fire risk. A chainsaw can produce sparks that could start a fire. Inspect the chain catcher and replace it if it is damaged. WARNING! The warning text warns of the risk of personal injury if the instructions are not followed. NOTE! The warning text warns of the risk of material damage if the instructions are not followed. Safety regulations !

4 – English Special tools 4 5 8 11 12 10 1 2 3 7 6 9

English – 5 Item Description Used for Order no. 1 Clutch tool Centrifugal clutch 502 54 16-01 2 Piston stop Locking crankshaft 502 54 15-01 3 Stop plate Locating intake gaiter 502 54 17-01 4 Fuel filter hook Withdrawing the fuel filter 502 50 83-01 5 Allen key For M5 bolts 502 50 18-01 6 Puller Frame bearing 504 90 90-02 7 Sleeve, sealing ring Removing flywheel 502 54 20-01 8 Mandrel, sealing ring Removing crankshaft 502 54 21-01 9 Cover plate Sealing during pressure testing 502 54 11-02 10 Pressure tester Connection to cylinder 503 84 40-02 11 Feeler gauge Adjusting ignition module 502 51 34-02 12 Clamp stand Clamping the saw 502 51 02-01 13 Pressure gauge Pressurisation during testing 502 50 38-01 14 Piston fitting kit Fitting piston 502 50 70-01 15 Test plug Checking ignition module 502 71 13-01 16 Rev counter Adjusting carburettor 502 71 14-01 17 Removal tool Removing crankshaft 502 51 61-01 18 Assembly pliers Fitting spark plug guard 502 50 06-01 19 a Assembly tool right-hand thread 502 70 45-06 19 b Assembly tool left-hand thread 502 70 45-07 19 c Assembly tool Sleeve 502 70 84-01 20 Stop plate Removing crankshaft 502 54 18-01 14 15 16 19 a 20 18 17 13 19 b 19 c Special tools

6 – English Displacement Cylinder bore Stroke Max power/speed cm 3 /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 42.0 / 1.65" 32.5 / 1.28" 2.5/ 3.4 /9,600 350: 49.4 / 3.0 44.0 / 1.73" 32.5 / 1.28" 2.3/ 3.1 /9,000 351 /G: 49.4 / 3.0 44.0 / 1.73" 32.5 / 1.28" 2.3/ 3.1 /9,000 Spark plug gap Ignition system Air gap Carburettor type mm/inches mm/inches 340: 0.5 / 0.02" FHP CD 0.3 / 0.012" Walbro HDA 154A (159A US only) 345: 0.5 / 0.02" FHP CD 0.3 / 0.012" Walbro HDA 154A (159A US only) 346XP/G: 0.5 / 0.02" FHP CD 0.3 / 0.012" Walbro HDA 154A (159A US only) 350: 0.5 / 0.02" FHP CD 0.3 / 0.012" Walbro HDA 154A (159A US only) 351 /G: 0.5 / 0.02" FHP CD 0.3 / 0.012" Walbro HDA 154A (159A US only) Effective cutting length Chain speed at Chain pitch Drive link cm/inches max power – revs mm/inches mm/inches m/s – rpm 340: 30-48 / 12"-19" 17.3 / 9,000 8.25 / 0.325" 1.3 / 0.050" - 1.5 / 0.058" 345: 30-48 / 12"-19" 17.3 / 9,000 8.25 / 0.325" 1.3 / 0.050" - 1.5 / 0.058" 346XP/G: 30-48 / 12"-19" 18.5 / 9,600 8.25 / 0.325" 1.3 / 0.050" - 1.5 / 0.058" 350: 30-48 / 12"-19" 17.3 / 9,000 8.25 / 0.325" 1.3 / 0.050" - 1.5 / 0.058" 351 /G: 30-48 / 12"-19" 17.3 / 9,000 8.25 / 0.325" 1.3 / 0.050" - 1.5 / 0.058" Technical data

English – 7 Technical data Idling speed Engagement speed Max. speed Spark plug rpm rpm rpm 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 350: 2,700 3,800 13,000 Bosch RCJ 7Y, NGK BPMR 7A 351 /G: 2,700 3,800 13,000 Bosch RCJ 7Y, NGK BPMR 7A rpm Fuel tank capacity Oil pump capacity at Oil tank capacity Automatic oil pump Litres/US pints 8,500 rpm, Litres/US pints ml/min 340: 0.5 / 1.06 9 0.25 / 0.53 Yes 345: 0.5 / 1.06 9 0.25 / 0.53 Yes 346XP/G: 0.5 / 1.06 5 - 10 0.28 / 0.59 Yes 350: 0.5 / 1.06 5 - 10 0.25 / 0.53 Yes 351 /G: 0.5 / 1.06 5 - 10 0.28 / 0.59 Yes GAS OIL Weight without bar and chain Weight with bar and chain Heated hand grips kg / lbs kg / lbs 340: 4.7 / 10.4 5.5 / 12.1 - 345: 4.7 / 10.4 5.5 / 12.1 - 346XP: 4.8 / 10.6 5.6 / 12.2 - 346XPG: 4.8 / 10.6 5.6 / 12.2 Yes 350: 4.8 / 10.6 5.6 / 12.2 - 351: 4.8 / 10.6 5.6 / 12.2 - 351G: 4.8 / 10.6 5.6 / 12.2 Yes

8 – English The carburettor works in different ways depending on the setting: • Cold start mode • Idling mode • Part throttle mode • Full throttle mode In the cold start mode the choke valve (D) is completely closed. This increases the vacuum in the carburettor so that fuel is sucked through the diffuser jets faster (E). Construction and function Carburettor • 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. The other side of the diaphragm sucks in the fuel. • The metering unit (A) which contains the jets and the fuel control mechanism. This measures out the right amount of fuel to suit the speed of the saw and the power demand. • The mixing unit (B) consists of the choke, diffuser jets and throttle valve. This is where the air and fuel are mixed to create a flammable mixture. The carburettor consists of three sub-systems:

English – 9 Construction and function In part throttle mode the throttle valve (F) is par- tially open. Fuel is supplied through the diffuser jets (E). In full throttle mode both valves are open and fuel is supplied through all the diffuser jets (E). 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 diffuser jet (E).

HUSQVARNA CHAINSAW 340 345 346XP Full Service & Repair Manual

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