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21

3

Fuel system

Symptom

Trouble Shooting Guide

 

Probable causes

Stop screw for the throttle not working

Fuel tank/hose

Fuel filter blocked

The fuel hose blocked

Air in fuel ducts

Incorrect/poor fuel

Pump diaphragm

Vacuum pulse leakage

Vacuum pulse duct blocked

Loose screw(s) on the pump cover

Faulty pump diaphragm

Flow bellows

Flow bellows damaged

The needle valve faulty

Carburettor is not fitted correctly

Faulty heat insulation seal

Needle valve’s lever

Lever arm damaged

Lever arm too high

Lever arm too low

Lever arm does not work correctly

Needle valve’s spring

The spring is deformed

The spring is not fitted correctly

Control diaphragm

Diaphragm is damaged

Faulty seal

Needle valve

Valve jams

Valve worn

Foreign object in the valve guide

Dif

ficult to start

Flooding, fuel leakage

Dif

ficult to prime when starting

Engine does not idle

Idles too slowly

Idling does not stabilise

Stops when idling

Engine does not accelerate

Engine stops when decelerating

Poor acceleration capacity

Poor performance at high speed

Starting

Low speed

Acceleration/

Deceleration

High speed

Summary of Contents for 324HDA

Page 1: ...Workshop manual 324LX 324RX 324HDA English ...

Page 2: ..._______________________________ 3 2 Ignition system ____________________________ 7 3 Fuel system _____________________________ 13 4 Centrifugal clutch _________________________ 25 5 Angle gear_______________________________ 29 6 Cylinder block and valve mechanism__________ 33 7 Piston crankshaft and crankcase ____________ 39 8 Tools ___________________________________ 45 ...

Page 3: ... Surfaces which the seal shall seal against must also be completely undamaged Lubricate the sealing lip with grease before it is fitted and ensure that it is not damaged e g by shoulders and splines on a shaft Use tape or a conical sleeve as protection It is important that the sealing ring faces in the right direction for it to act as it is intended The workshop used to carry out repairs must be e...

Page 4: ...3 1 1 Starter Contents Dismantling ___________________________________ 4 Assembly ____________________________________ 5 Replacing the drive _____________________________ 6 ...

Page 5: ... allow it to rotate backwards until the spring tension ceases Loosen the spring tension Pull out the starter cord about 30 cm Slow the starter pulley with your thumb Lift the starter cord up out of the cut out on the starter pulley Let the starter pulley rotate backwards until the spring tension ceases Dismantle the screw and drive spring Carefully lift off the starter pulley so that the return sp...

Page 6: ... as small as possible and enters the cut out on the starter pulley Wind the cord 3 turns anti clockwise around the starter pulley Lubricate the return spring and position the starter pulley Fit the drive spring A and the screw B Lubricate the return spring and the starter pulley s stub axle with cold resistant grease or thin oil Move the starter cord through the guide in the starter housing Guide ...

Page 7: ...holding the cylinder cover so that it sits loosely 2 Check that the rubber bushing A is in position 3 Insert the starter under the cylinder cover and press in the lower edge of the starter against the rubber bushing 4 Fit the 3 screws and tighten the screws holding the cylinder cover 5 Check that the starter works Replacing the drive Dismantle the drive with the help of slip joint pliers Insert a ...

Page 8: ... 2 Ignition system Contents Checking the spark ___________________________ 8 Replacing the spark plug cap __________________ 10 Dismantling ________________________________ 11 Assembly _________________________________ 12 ...

Page 9: ...nged 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 Screw the spark plug into position with your fingers until the spark plug seal rests against the cylinder Tighten using a spark plug spanner a further 1 8 1 4 turn 1 2 turn when the spark plug is new Check if a spark...

Page 10: ...move the short circuit cable from the ignition coil If the plug now sparks the fault is either in the stop switch or the short circuit cable Change the switch as needed and check to see if the cable insulation is damaged See Throttle in chapter 3 Fuel system Use pliers no 502 50 06 01 to make a hole in the ignition lead When a part of the ignition lead has been cut off it helps to use the pliers n...

Page 11: ...ured value 0 75 0 92 Ω The ignition coil should be replaced when the measured values are not met Now check the ignition coil s secondary winding Measured value 6 1 9 3 kΩ The ignition coil should be replaced when the measured values are not met Secondary winding Connect a universal instrument between elements B and C Measured value 6 1 9 3 kΩ The ignition coil should be replaced when the measured ...

Page 12: ... coil Dismantling Dismantle the air filter cowling cylinder cover and fan housing cover with fitted clutch housing Remove the screws holding the ignition coil and lift off the coil Dismantle the centrifugal clutch from the flywheel Dismantle the centrifugal clutch from the flywheel Use tool no 531 00 48 70 or for example the shaft of puller 502 51 49 01 to prevent the flywheel from rotating Insert...

Page 13: ...mbly Clean all components before assembling Check that the key in the flywheel is undamaged and fit the flywheel Fit the ignition coil Do not tighten the screws Place the feeler gauge 502 51 34 02 between the magnets on the flywheel and the ignition coil Tighten the screws on the ignition coil and remove the feeler gauge Assemble the centrifugal clutch See chapter Centrifugal clutch Assemble the o...

Page 14: ..._________ 15 Fuel filter __________________________________ 15 Carburettor ________________________________ 16 Assembly _________________________________ 20 Carburettor settings _________________________ 20 Trouble Shooting Guide ______________________ 21 Throttle ___________________________________ 22 Fuel system ...

Page 15: ...ver the air filter by pushing together the spring clip folding down the cover and lifting off from the cut out in the lower edge of the air filter holder WARNING Do not clean not the filter with petrol Hazardous Clean the filter in warm soapy water A damaged filter should be replaced with a new filter TIP Use Husqvarna s cleaning agent Active Cleaning no 505 69 85 70 NOTE Do not blow the filter cl...

Page 16: ...of the valve housing with the help of a small screwdriver Push together the valve with your fingers and check that its sealing lips are not damaged Ensure that the two small holes in the valve housing are open Fuel filter The fuel filter can be removed through the tank s fill hole Fuel filter The fuel hose in the tank contains a fuel filter It is accessible through the fill hole Pull out the filte...

Page 17: ...e how they are connected so that the fuel pump works as intended With the help of the fuel pump s bellows press fuel through the carburettor and fill all ducts with fuel Any vapour bubbles that block the ducts are pushed out In doing so helps to start the engine Dismantling the carburettor Dismantle the valve mechanism If the valve or its bearing are damaged the entire mechanism should be replaced...

Page 18: ...emove the pump diaphragm and its gasket Check the diaphragm for wear to the valve flaps 2 Hold it for example up to the light to discover holes in the material Clean the fuel screen 1 Remove it for replacement if necessary using a needle NOTE Do not lose the conical spring A that sits between pump diaphragm and the carburettor housing and the small filter disc B between carburettor housing and the...

Page 19: ...tting too much fuel Too low setting too little fuel Dismantle the main jet by using a small screwdriver to pry it out the carburettor housing The carburettor s main jet A can be dismantled for replacement Use a small screwdriver and pry the jet out of the carburettor housing Exercise care so that the small O ring B under the jet is not lost NOTE Do not dismantle the plastic pipe in the valve housi...

Page 20: ...arburettor is sealed Connect the pressure tester no 531 03 06 23 to the fuel inlet E on the carburettor Pump up the pressure to 50 kPa Lower the carburettor in a vessel with petrol in order to discover any leaks more easily No leakage is permitted Assembling the carburettor Clean and inspect all parts Worn or damaged parts are replaced with new ones Pay attention to the following when the carburet...

Page 21: ... holder Carburettor settings Only the idle speed can be adjusted Idle speed 2900 3300 rpm Carburettor settings The carburettor has fixed jets for both the low speed and high speed and cannot be adjusted The only setting necessary is the adjustment of the idle speed with the adjuster screw Idle speed 2900 3300 rpm Use the tachometer no 502 71 14 01 when the idle speed is adjusted The engine should ...

Page 22: ... Needle valve s lever Lever arm damaged Lever arm too high Lever arm too low Lever arm does not work correctly Needle valve s spring The spring is deformed The spring is not fitted correctly Control diaphragm Diaphragm is damaged Faulty seal Needle valve Valve jams Valve worn Foreign object in the valve guide Difficult to start Flooding fuel leakage Difficult to prime when starting Engine does not...

Page 23: ...e pressed correctly down in their channels so that they are not pinched when the two throttle halves are screwed together Do not forget to put the vibration element B in position before the throttle halves are put together Lubri cate the vibration element with soapy water This facilitates fitting the throttle on the shaft Fit together the throttle halves using the 5 screws but do not tighten them ...

Page 24: ...ismantling Ensure that the return springs A and B are positioned using the correct method Do not forget to fit the locking spring C Position the throttle cable and the short circuit cable in their channels so that they are not pinched when the two throttle halves are screwed together ...

Page 25: ...24 3 Fuel system ...

Page 26: ...25 4 Centrifugal clutch 4 4 Contents Dismantling ________________________________ 26 Assembly _________________________________ 27 Replacing the clutch drum and drive axle ________ 27 Centrifugal clutch ...

Page 27: ...ent speed has been carefully tested so that the engine can idle without the cutting equipment s drive shaft rotating Dismantling Dismantle all covers so the clutch becomes accessible Dismantling Dismantle the air filter cowling and cylinder cover Dismantle the fan housing cover with fitted clutch cover Dismantle the clutch from the flywheel Dismantle the centrifugal clutch from the flywheel Use to...

Page 28: ...lide the throttle forwards Loosen the screws B and pull out the shaft Replacing the clutch drum and drive axle Dismantle the clutch cover with fitted shaft Remove the screws A one on each side and slide the throttle forwards on the shaft so its fastening with the clutch cover becomes accessible Loosen the screws B and pull out the shaft Dismantle the clutch drum from the drive axle Hold the drive ...

Page 29: ...t the bearing falls out of the housing The inner diameter of the clutch drum must not exceed Ø 55 0 mm Assemble in the reverse order as set out for dismantling Check the clutch drum for wear The internal diameter must not exceed Ø 55 0 mm If this is the case replace the clutch drum Fit the ball bearing circlip and clutch drum in the reverse order as set out for dismantling Screw the drive axle ont...

Page 30: ...29 5 Angle gear 5 5 Contents Dismantling ________________________________ 30 Assembly _________________________________ 31 Angle gear ...

Page 31: ... the same time efficient In other words the power from the engine via the drive axle should be angled so that the cutting tool works parallel with the ground Remove the circlips holding the bearings on the input respective output shafts Heat the entire angle gear to approx 110 C and first dismantle the input axle and then the output axle 4 Remove the support washers and the dust protection disc 5 ...

Page 32: ... side faces outwards Heat the gearbox to approx 110 C and first place the output axle in position and then the input axle Make sure the bearing bottoms in its seating Fit the circlips B and C Make sure they lie correctly in their grooves Assemble remaining parts in the reverse order as set out for dismantling NOTE Do not forget the circlip A holding the bearing on the input axle Dismantle the bear...

Page 33: ...32 5 Angle gear ...

Page 34: ...lve mechanism Contents Compression test ___________________________ 34 Check the valve play ________________________ 34 Camshaft gear _____________________________ 35 Dismantling ________________________________ 37 Standard dimensions wear tolerances __________ 38 ...

Page 35: ... choke valve is open and that the throttle is fully open Turn over the engine with the starter Compression test Empty the fuel tank and fit a compression gauge in the spark plug hole Set the choke in the open position and the throttle at full throttle Turn over the engine powerfully with the starter approximately 2000 rpm Read the compression gauge Repeat the test procedure a number of times and c...

Page 36: ... that the ventilation duct is not clogged Fit the valve cover Camshaft gear Press out the camshaft gear s bearing axle using a suitable punch 3 mm Pull the belt to one side and lift out the gear Camshaft gear Dismantle the following Air filter cowling cylinder cover spark plug To make the following setting easier also dismantle the ignition coil and fan housing cover with fitted clutch housing and...

Page 37: ... gear should point straight up 2 Move the cam belt to one side and insert the camshaft gear Pay particular attention so that the triangular marking A on the gear points straight up NOTE It is very important that the cam belt and with that even the crankshaft do not rotate during this procedure If this occurs the valve timing will be wrong and the risk of engine failure will be high Fit the axle fo...

Page 38: ...e time so the fuel hoses do not need to be dismantled Dismantle the heat guard which is screwed onto the cylinder block using 3 screws Dismantle the oil hose with the help of flat nose pliers Dismantle the centrifugal clutch the drive for the starter and the flywheel See all relevant sections Dismantle the camshaft gear Remove the 6 screws holding the crankcase against the cylinder block Remove th...

Page 39: ...er exhaust 3 435 3 450 mm 3 380 mm Valve spindle diameter inlet 3 470 3 485 mm 3 400 mm Valve guide inner diameter 3 500 3 518 mm 3 560 mm Clearance valve spindle valve guide exhaust 0 050 0 083 mm 0 120 mm Clearance valve spindle valve guide inlet 0 015 0 048 mm 0 098 mm Timing gear inner diameter 4 020 4 050 mm 4 100 mm Cam height 22 097 mm 21 797 mm NOTE When the valve guides are worn in excess...

Page 40: ...e 7 7 Contents Dismantling ________________________________ 40 Non return valve ____________________________ 41 Piston ____________________________________ 41 Assembly _________________________________ 42 Piston crankshaft and crankcase ...

Page 41: ...ealing rings when carrying out a service Dismantling Dismantle all components so that only the crankcase and crankshaft remain Dismantle the crankcase half and crankshaft piston Dismantle the piston from the connecting rod Dismantling Dismantle all components so that only the crankcase and crankshaft remain Dismantle the crankcase half and crankshaft piston See the respective sections for detailed...

Page 42: ...alve with regard to damage and wear which can cause leakage Pay particular attention to the leaf spring A Check when assembling that the cut off corner on the leaf spring and the stroke limiter are positioned the right way round Use Loctite on the screws when assembled Piston It is important when servicing that the different piston rings are fitted in the right grooves on the piston as they have a...

Page 43: ...using Assembly 1 Lubricate the sealing rings with a few drops of oil and slide them onto the crankshaft s axle journals Turn them so the smooth side faces outwards 2 Lubricate the piston and piston rings with oil 3 Place the cam belt on the gear and ensure that it rotates in the same direction as before 4 Slide the piston into the cylinder and the belt in the cam belt housing Check that the sealin...

Page 44: ...urned towards the air filter Fill new oil SAE 10W 40 in the crankcase Use semi synthetic oil or mineral oil for the lowest oil consumption especially when the engine is new When the ventilation hose is fitted between the air filter and cam cover ensure that the long end A of the hose is turned towards the air filter Fill new oil SAE 10W 40 in the crankcase Use semi synthetic oil or mineral oil for...

Page 45: ...44 7 Piston crankshaft and crankcase ...

Page 46: ...______________________ 46 Fuel system _____________________________ 46 Centrifugal clutch _________________________ 46 Angle gear ______________________________ 46 Cylinder block and valve mechanism __________ 47 Piston crankshaft and crankcase ____________ 47 Workshop equipment ______________________ 47 ...

Page 47: ...502 50 18 01 502 50 19 01 531 00 60 76 502 50 83 01 501 60 02 03 503 97 64 01 502 50 18 01 505 69 85 70 502 51 49 01 531 00 48 70 531 03 06 23 505 38 13 08 502 02 61 02 502 50 18 01 531 00 48 70 Ignition system Centrifugal clutch Angle gear Starter Fuel system ...

Page 48: ...ls 502 51 03 01 502 71 14 01 531 03 06 23 502 50 18 01 505 69 85 70 101 64 23 48 505 38 13 08 502 50 18 01 504 90 90 01 503 26 70 01 Cylinder block and valve mechanism Piston crankshaft and crankcase Workshop equipment ...

Page 49: ...2004W26 114 02 94 26 ...

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