334T 338XPT 336 339XP English
CONTENTS Introduction .................................................... 3 Safety instructions ......................................... 4 Symbol explanation ....................................... 5 Technical Data ................................................ 6 Tools ................................................................ 8 Trouble shooting .......................................... 10 Service data 334T/338XPT ........................... 12 Service data 336/339XP ............................
INTRODUCTION General Layout This Workshop Manual provides a comprehensive description of how to trouble shoot, repair and test the chain saw. A description of different safety measures that should be taken during repair work is also given. This Workshop Manual can be used in two different ways: Safety Repair of a particular system NOTE! The section dealing with safety must be read and understood by all those carrying out repair work or service on the chain saw.
SAFETY REGULATIONS General instructions Special instructions The workshop where chain saw repairs are to be done must be equipped with safety equipment as set out in local provisions. The fuel used in the chain saw has the following hazardous properties: No one may repair the chain saw unless they have read and understood the content of this Workshop Manual. • The fluid and its vapour are poisonous. • Can cause skin irritation. • Is highly inflammable.
SYMBOL EXPLANATION Symbols WARNING! Chain saws can be dangerous! Careless or incorrect usage can result in serious injury even death to operator or others. Inspection and/or maintenance should be carried out with the engine switched off, and with the stop switch in the "STOP" position. Read through the Operator Guide carefully and understand the content before using the chain saw.
TECHNICAL DATA Stroke volume cm3/cubic inch Cylinder diameter Ø mm/Ø inch Stroke length mm/inch Max.
TECHNICAL DATA Idling speed r/min Engage speed r/min Max.
TOOLS 8 – English 1 2 3 4 5 6 8 9 10 11 12 13 14 15 7
TOOLS The tools listed here are service tools intended for use on the chain saw in question. In addition to these tools, a standard set of hand tools is required. Pos Description Used for Order No.
TROUBLE SHOOTING Trouble shooting chart Idling (low speed) (continued) The different faults that can occur on the chain saw are divided into four groups as follows. Within each group possible operating faults are listed to the left while the probable fault alternatives are listed to the right. The most likely fault is listed first, etc.
TROUBLE SHOOTING High speed Acceleration and retardation Will not run at full throttle Adjust H-screw Blocked air filter Tank ventilator blocked Blocked fuel filter Blocked fuel line Loose or faulty fuel pipe Impulse channel leaking Blocked impulse channel Cover on the carburettor’s pump side is loose Faulty pump diaphragm Leaking inlet manifold (rubber) Loose carburettor mounting Control system set too low Damaged control system Incorrectly fitted control system Leaking diaphragm/cover plate Control sys
SERVICE DATA 334T/338XPT 2-3 15 20-26 Character key The numbers by bolted components represent the tightening torque in Nm. ▲ ■ ● ❑ ❍ = Lubricate using two-stroke oil. = Lubricate using engine oil. = Lubricate using grease. = Glued using 2 component adhesive. = Sealed using silicone.
SERVICE DATA 334T/338XPT 2,5-4 1-2 2-3 8-10 10-15 * 6-7 2-3 2-3 2,5-4 2,5-4 20-26 English – 13
SERVICE DATA 336/339XP 15 20-26 10-15 2-3 * 8-10 8-10 Character key The numbers by bolted components represent the tightening torque in Nm. ▲ ■ ● ❑ ❍ = Lubricate using two-stroke oil. = Lubricate using engine oil. = Lubricate using grease. = Glued using 2 component adhesive. = Sealed using silicone.
SERVICE DATA 336/339XP STOP 2,5-4 6-7 2-3 2-3 2,5-4 2,5-4 20-26 English – 15
SAFETY EQUIPMENT Chain brake Dismantling 1. Check that the chain brake is off and dismantle the bolt (A) and the clutch cover. A WARNING! Check that the brake is on. Otherwise the pressure spring can fly out and cause personal injury. 2. Remove the circlips (B) and (C) then push/knock out the pins. 3. Remove the handle. B 4. Undo the four bolts (D) and remove the cover. C D D D D 5. Remove the pressure spring by loosening the rear edge with a screwdriver. 6.
SAFETY EQUIPMENT Assembly Assemble the chain brake as follows: 1. Bolt together the knee joint and brake band. 2. Grease the knee joint’s moving parts and assemble the unit in the cover and knock in the pin (E). 3. Fit the kickback guard, insert the two pins and fit the circlips (B) and (C). E B C 4. Apply the brake and fit the spring. Use a screwdriver to press down the rear edge. 5. Fit the cover and tighten the four bolts (D). 6. Release the brake and fit the clutch cover on the chain saw.
SAFETY EQUIPMENT Chain catcher Dismantle the chain and bar. See the Operator Guide. Check the spike (J), does not apply to 333, and the chain catcher (K). Replace any components if damaged. The bolts should be tightened to 4 Nm. Assemble the chain and bar. See the Operator Guide. Muffler WARNING! Do not touch the muffler until it has cooled. Risk for burns. Dismantling Dismantle the muffler as follows: 1. Dismantle the muffler guard by removing the two bolts (A). 2.
SAFETY EQUIPMENT Throttle lock and stop function Dismantling, 334T, 338XPT Dismantle the throttle lock as follows: 1. Dismantle the clutch cover and carburettor cover. 2. Knock out the pins (B) and (C) from the left and undo the bolt (D), now pull up the throttle lock (A). 3. Disconnect the choke rod (G) from the carburettor using a small screwdriver and dismantle the choke lever/stop button. 4. Using long-nose pliers dismantle the lock plate (E). 5. Disconnect the throttle’s bearing (F).
SAFETY EQUIPMENT Assembly 334T, 338XPT Assemble the components as follows: 1. Assemble the electrical leads to the lock plate (E) and choke lever/start control (J). J 2. Slide in the throttle (H). At the same time, fit the throttle rod (I) on the throttle. Do not hook on the bearing (F) yet. E I H 3. Using long-nose pliers assemble the lock plate (E). Bolt in position using bolt (D). 4. Slide up the choke lever/start control (J). D E F 5. Fit the pin from the right (C).
SAFETY EQUIPMENT Dismantling 336, 339XP 1. Remove the stop button (A) and both side covers (B) using a small screwdriver. 2. Tap out the pins (C) and (D) using a drift. 3. Remove the throttle lock (E) together with the spring (F). 4. Remove the throttle trigger (G) by pressing the front edge upwards and the rear edge downwards at the same time. 5. Disconnect the throttle wire (H) from the throttle trigger. A C D B H E F G 6.
SAFETY EQUIPMENT Assembly 336, 339XP I Assemble the parts as follows: 1. Attach the throttle wire (H) to the steel wire and pull back the steel wire and throttle wire through the tank unit. 2. Connect the throttle wire (H) to the throttle valve (I) and then fit the carburettor cover. 3. Connect the throttle wire (H) to the throttle trigger (G). 4. Fit the throttle trigger (G) by pushing it upwards and forwards at an angle. 5. Fit the spring (F) and throttle lock (E).
STARTER WARNING! • The return spring is under tension when in its cassette in the starter and can, with careless handing, fly out and cause personal injury. • Care must be exercised when replacing the recoil spring or the starter cord. Wear protective glasses. Dismantling 1. Undo the four bolts holding the starter (A) and air conductor (B) in position. A 2. Pull the cord out 20-30 cm and lift it into the cut-out on the starter pulley’s outer edge.
STARTER Cleaning and inspection Clean all components and check the following: 1. Starter cord. 2. The dogs on the starter pulley. 3. That the starter dogs on the flywheel are intact, spring back towards the centre and run easily. Assembly 1. Lubricate the new return spring using thin oil without removing it from the cassette. 2. Carefully fit the spring cassette in the starter housing so that the spring does not fly out and cause personal injury. 3.
IGNITION SYSTEM Dismantling 1. Dismantle the starter (A) and air conductor (B). 2. Remove the spark plug and insert the piston stop (C) in the spark plug hole. See service tools. A C B 3. Loosen the cable (D) from the ignition module. Undo the two M4 bolts (E) and lift out the ignition module (F). 4. If the ignition module is to be replaced, pull out the contact spring from the spark plug guard and dismantle the parts. 5.
IGNITION SYSTEM Cleaning and inspection Clean all parts, especially the tapers on the flywheel and shafts. Check the flywheel for cracks or any other signs of damage. Assembly 1. Fit the piston stop fully. 2. Fit the starter dogs (G). 3. Fit the flywheel on the crankshaft. Rotate a little so that the flywheel’s key fits in the keyway on the shaft. 4. Fit the counterbalance washer (I) in the slot on the flywheel. Use a 13 mm spanner and tighten the nut (H) to 20-26 Nm. 5.
CENTRIFUGAL CLUTCH Dismantling 1. Dismantle the clutch cover. 2. Remove the spark plug and insert the piston stop (A) in the spark plug hole. See service tools. 3. Use a 19 mm spanner and dismantle the clutch hub. NOTE! Left-hand thread. 4. Remove the washer (B), clutch drum (C) and needle bearing (D). A B C 5. D If necessary, dismantle the clutch shoes as follows: A. Place the clutch hub in a vice. B. Using a screwdriver press out the shoe holder. C. Dismantle the shoes and springs.
CENTRIFUGAL CLUTCH Assembly 1. When changing the springs assemble as follows: A. Fit the two clutch shoes and the two springs and set up the unit in a vice. B. Tighten the vice so that the shoe holder can be pressed down between the clutch shoes. 2. Grease and fit the needle bearing (D), clutch drum (C) and washer (B). B C 3. Use a 19 mm spanner and fit the clutch hub. NOTE! Left-hand thread. 4. Remove the piston stop (A) and fit the spark plug. Tightening torque: 15 Nm. 5. Fit the clutch cover.
CARBURETTOR Description WARNING! The fuel used in the chain saw has the following hazardous properties: • The fluid and its vapour are poisonous. • Can cause skin irritation. • Is highly inflammable. The drawings accompanying this description do not correspond with the carburettor on the chain saw. They show purely the principle for the design and function. The carburettor is based on three sub-systems: Metering unit The needles and the fuel’s control functions are located in the metering unit (A).
CARBURETTOR Operation The carburettor operates differently in the following modes: Cold start mode In the cold start mode the choke valve (D) is fully closed. This increases the vacuum in the carburettor and fuel is easier to suck from all the diffuser jets (E, F and G). The throttle valve (H) is partly open. Idling mode In the idling mode (H) the throttle valve is closed. Air is sucked in through an aperture in the throttle valve and a small amount of fuel is supplied through the diffuser jet (F).
CARBURETTOR Primer pump The primer pump is designed to make it easier to start the engine when cold. The pump fills the carburettor with fuel before an attempt is made to start. This also prevents bubbles of vapour from blocking the narrow fuel channels. If the pump does not work it must be replaced. Note the way the fuel pipes are connected in order to simplify assembly. 1. 2. 3. 4.
CARBURETTOR Dismantling, 334T, 338XPT WARNING! The fuel used in the chain saw has the following hazardous properties: • The fluid and its vapour are poisonous. • Can cause skin irritation. • Is highly inflammable. 1. Dismantle the chain and bar. See the Operator Guide. 2. Dismantle the carburettor cover (R). 3. Dismantle the air filter (S), the two bolts and the air filter holder (U).
CARBURETTOR 7. Dismantle the cover (A) on the metering unit and carefully remove the control diaphragm (B) with gasket (C). 8. Dismantle the bolt (D) and lift out the needle valve (P) with lever (E), shaft and spring (F). 9. Dismantle the cover (J) on the pump unit and carefully remove the gasket (K) and pump diaphragm (M). 10. Use a needle or the like and remove the fuel screen (N). 11. Dismantle the high and low needles (H and L). Use side cutters if necessary to remove the locking caps. 12.
CARBURETTOR Dismantling 336, 339XP R WARNING! The fuel used in the chain saw has the following hazardous properties: • The fluid and its vapour are poisonous. • Can cause skin irritation. • Is highly inflammable. 1. Dismantle the chain and bar. See the Operator Guide. 2. Dismantle the carburettor cover (R). 3. Remove the air filter (S). 4. Undo the two screws (V) that hold the air filter holder (U) and carburettor. S 5. Free the choke control (X) from the tank unit and unhook it. 6.
CARBURETTOR 7. Dismantle the cover (A) on the metering unit and carefully remove the control diaphragm (B) with gasket (C). 8. Dismantle the bolt (D) and lift out the needle valve (P) with lever (E), shaft and spring (F). 9. Dismantle the cover (J) on the pump unit and carefully remove the gasket (K) and pump diaphragm (M). 10. Use a needle or the like and remove the fuel screen (N). 11. Dismantle the high and low needles (H and L). Use side cutters if necessary to remove the locking caps. 12.
CARBURETTOR Cleaning and inspection of the carburettor WARNING! Fuel has the following hazardous properties: • The fluid and its vapour are poisonous. • Can cause skin irritation. • Is highly inflammable. Clean all units in clean petrol. WARNING! Never direct the compressed air jet towards the body. Air can penetrate into the blood circulation, which means mortal danger. Use compressed air to dry the petrol on the components.
CARBURETTOR 5. Fit the high speed needle (H) as follows: A. Screw in the new H-needle clockwise until it bottoms. Then anticlockwise 3 1/2 turns. B. Press a new locking cap onto the H-needle to the first stop, i.e. the locking cap should not be fixed. 6. Fit the low speed needle (L) as follows: A. Screw in the new L-needle clockwise until it bottoms. Then anticlockwise 1 3/4 turns. B. Press a new locking cap onto the L-needle to the first stop, i.e. the locking cap should not be fixed. 7.
CARBURETTOR Assembly 334T, 338XPT (continued) WARNING! The fuel used in the chain saw has the following hazardous properties: • The fluid and its vapour are poisonous. • Can cause skin irritation. • Is highly inflammable. Once the carburettor has been pressure tested assembly continues as follows: 1. Insert the carburettor a little and fit the throttle (X). Now insert the carburettor fully. 2. Fit the fuel pipe (V) using pliers with smooth jaws. Take care not to damage the pipe. 3.
CARBURETTOR Assembly 336, 339XP (continued) X Z Y WARNING! The fuel used in the chain saw has the following hazardous properties: • The fluid and its vapour are poisonous. • Can cause skin irritation. • Is highly inflammable. Once the carburettor has been pressure tested assembly continues as follows: 1. Fit the fuel pipe (Z) using pliers with smooth jaws. Take care not to damage the pipe. 2. Insert the carburettor a little and fit the throttle wire (Y). Then insert the carburettor fully. 3.
CARBURETTOR Carburettor Conditions Your Husqvarna product has been designed and manufactured according to specifications that reduce harmful gases. When you engine has consumed 8-10 tanks of fuel the engine has been "run-in". To ensure that it runs in the best possible way and emits as few harmful gases as possible after the running in period, let your dealer/service workshop that has a tachometer, adjust your carburettor so that it gives optimal performance.
TANK UNIT F WARNING! The fuel used in the chain saw has the following hazardous properties: • The fluid and its vapour are poisonous. • Can cause skin irritation. • Is highly inflammable. B A F Dismantling Dismantle the following parts: 1. Bar and chain. See the Operator Guide. 2. Centrifugal clutch. See the chapter "Centrifugal clutch". 3. Muffler. See the chapter "Safety equipment". 4. Carburettor. See the chapter "Carburettor". 5. Starter. See the chapter "Starter". 6.
TANK UNIT Changing the fuel hose and fuel filter 1. Take out the fuel filter with the attached hose with the help of a hook 502 50 83-01. 2. Pull the hose out through the rubber grommet. 3. Dismantle the rubber grommet. 4. Fit a new rubber grommet on a new hose so that the hose protrudes about 80 mm. 5. Insert the hose from the outside and press in the rubber grommet so that it is fastens in the hole. 6.
TANK UNIT Replacing the tank vent valve, oil tank 334T, 338XPT: 1. Pull out the valve’s rubber fastener using a pair of pliers. 2. Fit a new pin, vyon plug and valve in a new rubber fastener, place the unit in the hole in the tank from the outside. 3. Pull in the valve with fitted vyon plug and pin using a pair of long-nosed pliers from inside the tank. 1. Pull out the vyon plug (G) by pushing in a screwdriver and prising it out. Then pull out the plastic valve. 2.
TANK UNIT Replacing the impulse hose 1. Pull out the old impulse hose using pliers. 2. Insert the new impulse hose from the carburettor side and carefully pull it in from the engine side.
TANK UNIT WARNING! The fuel used in the chain saw has the following hazardous properties: • The fluid and its vapour are poisonous. • Can cause skin irritation. • Is highly inflammable. Assembly Assemble the following parts: 1. Fit the engine unit from the clutch side and at the same time move the oil hose (E). 2. Grab the intake manifold through the hole in the tank unit using flat pliers and carefully pull it up. 3. Fit the chain catcher and the bolts (C). D C F C 4.
AV-SYSTEM Anti vibration system WARNING! The fuel used in the chain saw has the following hazardous properties: • The fluid and its vapour are poisonous. • Can cause skin irritation. • Is highly inflammable. Dismantling Dismantle the following parts: 1. Bar and chain. See the Operator Guide. 2. Centrifugal clutch. See the chapter "Centrifugal clutch". 3. Muffler. See the chapter "Safety equipment". 4. Carburettor. See the chapter "Carburettor". 5. Starter. See the chapter "Starter". 6.
CRANKSHAFT, PISTON AND CYLINDER Dismantling Dismantle the following parts: 1. Bar and chain. See the Operator Guide. 2. Centrifugal clutch. See the chapter "Centrifugal clutch". 3. Muffler. See the chapter "Safety equipment". 4. Carburettor. See the chapter "Carburettor". 5. Starter. See the chapter "Starter". 6. Ignition system and the spark plug. See the chapter "Ignition system". 7. Tank unit. See the chapter "Tank unit".
CRANKSHAFT, PISTON AND CYLINDER Cleaning and inspection Clean all parts, scrape off any sealant from the crankcase and the cylinder’s contact surfaces. Remove carbon deposits from the following areas: 1. The piston crown. 2. Top of the cylinder bore (inside). 3. The cylinder exhaust port. Check the following: 1. That the cylinder’s surface coating is not worn. Especially the upper part of the cylinder. 2. That the cylinder is free of score marks. 3. That the piston is free of score marks.
CRANKSHAFT, PISTON AND CYLINDER Assembly Assembly of the piston and cylinder is carried out as follows: NOTE! Exercise care so that dirt and foreign particles do not enter dismantled parts. 1. Fit the bearing (C) using the a suitable mandrel. 2. Fit the inlet manifold (B) from the cylinder. Check that the inlet manifold is turned as illustrated. B 3. Lubricate the needle bearing and fit in the connecting rod little-end. 4. Replace the piston with the arrow facing the exhaust port.
CRANKSHAFT, PISTON AND CYLINDER Removing the decompression valve Disconnect the pipe from the nipples (B and C). Use a ring spanner (15 mm) to remove the valve from the cylinder. Check that the valve can be pressed in easily and springs back out again. If the valve is stiff it should be soaked in petrol for a while to loosen the particles of soot. It can then be blown clean with compressed air. C B Use a pressure tester to check that the non-return valve is working correctly.
BAR BOLT Dismantling Dismantle the following parts: 1. Bar and chain. See the Operator Guide. 2. Centrifugal clutch. See the chapter "Centrifugal clutch". 3. Muffler. See the chapter "Safety equipment". 4. Carburettor. See the chapter "Carburettor". 5. Starter. See the chapter "Starter". 6. Ignition system and the spark plug. See the chapter "Ignition system". 7. Tank unit. See the chapter "Tank unit". Continue to dismantle as follows: 8.
OIL PUMP Dismantling Dismantle the following parts: 1. Bar and chain. See the Operator Guide. 2. Centrifugal clutch. See the chapter "Centrifugal clutch". 3. Muffler. See the chapter "Safety equipment". 4. Carburettor. See the chapter "Carburettor". 5. Starter. See the chapter "Starter". 6. Ignition system and the spark plug. See the chapter "Ignition system". 7. Tank unit. See the chapter "Tank unit". 8. Cylinder and crankshaft. See the chapter "Crankshaft, Piston and Cylinder".
OIL PUMP Assembly A Assemble as follows: 1. Lubricate and fit the pump piston (B), spring and washer. Press in the unit and at the same time screw in the adjuster screw (A) with the spring and washer. F B 2. Fit the guide (C) and cover plate (D). C D Now assemble the following parts: 3. Cylinder and crankshaft. See the chapter "Crankshaft, Piston and Cylinder". 4. Tank unit. See the chapter "Tank unit". 5. Ignition system and the spark plug. See the chapter "Ignition system". 6. Starter.
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English – 55
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