Husqvarna 345FR Workshop Manual Download Page 21 | Manualshive

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Fuel system

The pump unit

This is where the pump diaphragm (E)
that pumps fuel from the tank to the carbu-
rettor’s measuring unit is found.

The diaphragm is affected by pressure
variations in the engine’s crankcase via an
impulse channel (F).

If the channel is blocked, by grease or
a wrongly facing gasket, for example,
the pump unit does not function and the
engine cannot be started.

The pump unit

Pumps fuel from the tank to the carburet-
tor.

The blending unit

Fuel and air are mixed here.

The blending unit

In this section of the carburettor fuel and
air are mixed in the proper proportions.

The choke and throttle valves are placed
here.

In the middle of the venturi (narrowest
part of the throughput) the main jet (D) is
found.

Dismantling the carburettor

Remove the control diaphragm and check
for damage.

Replace if required.

Dismantling the carburettor

Remove the 4 screws (A) holding the con-
trol diaphragm cover and lift off the cover.

Carefully remove the control diaphragm
(B) and gasket (C).

Check the diaphragm for holes and wear
on the pin (D).

Replace the diaphragm if required.

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Summary of Contents for 345FR

Page 1: ...Workshop manual English 545RX 545FR 545FX 545FXT 545RX 545RXT 345FR ...

Page 2: ......

Page 3: ...15 4 Centrifugal clutch _______________________ 31 5 Bevel gear ____________________________ 37 6 Cylinder and piston ______________________ 41 7 Crankshaft and crankcase ________________ 51 8 Tools _________________________________ 57 9 Technical data __________________________ 61 Husqvarna AB Sweden 2011 Workshop Manual Brushcutter Trimmer 545RX 545FR 545FX 545FXT 545RX 545RXT 345FR Contents ...

Page 4: ... Some of the work described in this workshop manual re quires special tools In each section where this is necessary there is a picture of the tool and an order number We recommend the use of special tools in order to avoid ex pensive damage to parts in question and personal injury and to provide an efficient repair procedure Contact faces and gaskets Ensure all surfaces are clean and free from gas...

Page 5: ...1 3 1 Starter Starter Contents Dismantling __________________________________ 4 Assembly ___________________________________ 5 Replacing the drive dogs _______________________ 6 ...

Page 6: ...be loosened or detached The screws are the so called captive type which means that they remain in place when the starter is removed Snap off the air guide plate 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 Remove the bolt in the centr...

Page 7: ...he 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 ...

Page 8: ...th the cord completely pulled out the cord pulley should be able to be turned at least an other half revolution Press the air guide plate on to the starter housing 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 drive dogs grip the starter pulley in the ...

Page 9: ...n spark _____________________ 8 Replacing the spark plug cover _________________ 10 Dismantling ________________________________ 10 Drive dogs _________________________________ 11 Assembly__________________________________ 12 Heated handles _____________________________ 12 ...

Page 10: ...the electrodes are worn more than 50 the spark plug should be changed If the engine does not start or misfires despite the spark plug showing no signs of wear try with a new spark plug 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 If the engine does not start or misf...

Page 11: ...e cables are correctly drawn and lie in the cable grooves Do not forget to check the cables in the throttle too See chapter 3 Throttle Tip Use an Ohmmeter in order to easily check if cable breakage has occurred due to pinching for example NOTE The stop switch has a non locking design and must be replaced with one of the same type If the plug now sparks the fault is either in the stop switch or the...

Page 12: ...into the spark plug cover to facilitate assembly before sliding the cable in place NOTE It is important that the tip of the ignition coil hits the centre of the ignition cable to prevent sparking Adjust the air gap Adjust the air gap as needed to the correct value Loosen the bolts Position the feeler gauge and press the ignition module against the flywheel Tighten the bolts and check the air gap a...

Page 13: ...ng a hot air gun if necessary or use puller no 502 51 49 01 If needed dismantle the generator supply ing power to the heated handles Dismantle the ignition module Dismantle the ignition module Remove the ignition cable from cable channel A Remove both bolts B Loosen the short circuit cable C from the ignition module Note the insulation sleeve D on the igni tion cable Drive dogs Remove the bolts Re...

Page 14: ...d The element can be damaged The heating element in the throttle is ac cessed when the throttle lock is pushed out of the throttle Pry off the locking catch and lift out the heating element A heating element is placed in the throttle lock for involuntary throttling Press the locking catch from the throttle making sure not to lose the spring A Pry off the locking catch B and lift out the heating el...

Page 15: ... bolt that holds the left grip on the handle Pull out handle from the handlebars and then the cables carefully and one at a time so that the steel wire does not loosen from the cables The heating element is located in a pocket in the outside of the handle Use flat nose pliers to pull out the heating element from the handle NOTE Do not pull the cables or their connections Connections can be easily ...

Page 16: ...2 14 Electrical system ...

Page 17: ...uel filter __________________________________ 17 Carburettor ________________________________ 18 Assembly__________________________________ 24 Carburettor settings__________________________ 25 Thumb throttle _____________________________ 27 Index finger throttle __________________________ 28 Trouble Shooting Guide ______________________ 30 ...

Page 18: ... Tank venting Slide the fuel tank so far forward that the fuel hose can be removed Tank venting Slide the fuel tank so far forward that the fuel hose A becomes accessible Slide the O ring backward and remove the hose from the nipple See also the Centrifugal clutch chapter if required In addition to the fuel tank and carburettor the fuel system consists of the air filter fuel filter and tank ventin...

Page 19: ...gers or with help of the 502 50 83 01 tool NOTE The fuel filter can get stuck under the shaft bushing in the tank Loosen the filter using a long screwdriver Do not pull on the hose since it can easily be pulled from the filter Clean the outside of the filter if it is not too dirty Replace the filter if required If the filter is not too dirty its surface can be cleaned with a brush Otherwise it mus...

Page 20: ...able G from the throttle valve shaft and lift off the carburet tor Prise off the fuel hoses C and D from the carburettor using a screwdriver Unhook the pressure rod E from the carburettor s valve shaft and lift of the air supply valve F Remove the throttle cable G from the throttle valve shaft and lift off the carburet tor The carburettor s design The carburettor can be divided into three differen...

Page 21: ...ret tor The blending unit Fuel and air are mixed here The blending unit In this section of the carburettor fuel and air are mixed in the proper proportions The choke and throttle valves are placed here In the middle of the venturi narrowest part of the throughput the main jet D is found Dismantling the carburettor Remove the control diaphragm and check for damage Replace if required Dismantling th...

Page 22: ...eakage remove the needle valve In the event of leakage remove the needle valve Loosen the bolt and remove the lever arm axle needle valve and spring Check the needle valve and the lever arm for damage or wear Replace damaged components with new ones Check the needle valve for damage on the tip and in the lever arm groove Check the lever arm for damage to the groove for the needle valve and wear on...

Page 23: ...manner Hold it up to a light as well to discover any holes in the material Carefully remove the fuel screen D us ing a needle for example Clean or replace the fuel screen NOTE During assembly the pump diaphragm should lie closest to the carburettor housing The carburettor s jets H and L can only be adjusted within a very limited area which is dependent on the sleeves A Dismantle the jets with the ...

Page 24: ... and dampers at the same time Assembling the carburettor Blow all channels in the carburettor compartment clean Press a new main jet in place using a punch until the edge of the jet lies flush with the recessed area in the carburet tor also refer to illustration above on dismantling of main jet Assembling the carburettor Blow the carburettor housing clean Fit a new main jet ...

Page 25: ...ly and that they close completely and tightly in the closed position Use Loctite on the valve screws NOTE Tension the return spring C on the choke shutter spindle sufficiently Otherwise the pawl for the start throttle setting will not work as intended Attach the various parts of the measuring unit in the reverse order as set out for dismantling Check that the lever arm lies flush with the carburet...

Page 26: ...on Assemble the jets H and L Place the sleeve A and the spring B on the jets and slide the components into the carburettor housing Note that the cut out in the sleeve should be turned to face the bar in the carburettor housing Use tool 530 03 55 06 to press in the sleeve and screw in the jet When the sleeve has been pressed in using the tool the jet can be adjusted freely Carefully screw the jet u...

Page 27: ...ying a combustible fuel air mixture to the cylinder The amount of this mixture is controlled by the throttle The mixture s composition of fuel and air is controlled by means of the adjustable H and L needles WARNING When testing the engine in connection with carburettor adjustment the clutch and clutch cover must be mounted together with the shaft and angle gear under all circumstances Otherwise t...

Page 28: ...ntil the speed has stabilised Adjust the idling speed T screw until the engine idles without stopping Turn the screw clockwise if the engine stops Turn the screw anticlockwise to lower the speed Fine adjustment Fine adjustment of the carburettor should be carried out after the engine has been run in The air filter should be clean and the cylinder cover fitted when all adjustments are made First ad...

Page 29: ...ocking sleeve turning as well Adjust the L jet so that the engine reaches its highest speed The L jet is then turned a 1 2 turn anticlockwise Now release the locking sleeve back to its home position The L jet is now correctly adjusted and the locking sleeve remains anticlockwise against the stop 5 If the speed exceeds 3 700 rpm reduce it with the aid of the idling speed s T screw T and make a new ...

Page 30: ...he throttle and remove bolts B and C Carefully separate the two halves of the throttle Check for wear on pins A and B Replace the throttle control C and lever arm D if necessary Check that the cables are properly pressed into the cut outs E and that the throttle cable F is in the right groove If necessary attach it with silicon adhesive in order to facilitate assembly Check that the protective bel...

Page 31: ...p D in order to check if replace ment is necessary The stop switch can also be disassem bled now and replaced if necessary Use a screwdriver to press the stop switch s wing locks E Tip Reassembly of the throttle easier if a thin steel wire is wrapped around the handle and bolt F in order to hold the throttle cable and short circuit cables in place ...

Page 32: ...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 Diffi cult to start Flooding fuel leakage Diffi cult to prime when starting Engine does not idle Idles too slowly Idling ...

Page 33: ...ch Centrifugal clutch Contents Dismantling ________________________________ 32 Assembly _________________________________ 34 Clutch drum Dismantling _____________________________ 34 Assembly _______________________________ 36 ...

Page 34: ...ad changes on the crankshaft The engagement speed has been carefully tested so that the engine can idle without the cutting equipment s drive shaft rotating Dismantling Loosen the fuel hoses from the carburettor and the fuel pump Dismantling The clutch is located between the fuel tank and the engine In order to be accessible the tank and handle holder must be moved forward on the shaft 1 Remove th...

Page 35: ... and remove the 3 bolts Lift off the front cover plate and the clutch shoes NOTE Do not lose the sleeve bearings found in the clutch shoes Twist apart the clutch Twist apart the clutch Remove the vibration dampers Remove the 4 screws holding the clutch cover and lift the engine body to the side Remove the vibration dampers Remove the 4 screws holding the clutch cover on the engine Lift the engine ...

Page 36: ...om the shaft Clutch drum Dismantling Separate the engine body and shaft as described previously 1 Loosen the screws A holding the clutch cover against the shaft 2 Pull away the clutch cover with the clutch drum and the drive axle from the shaft NOTE Make sure that the spring eye is pressed into the correct position Remove the screws and put the cover plates in position Tighten the bolts fit the cl...

Page 37: ...irclip Remove the circlip holding the ball bearing in place in the clutch housing by using circlip pliers Heat the clutch housing and remove the bearing Heat the clutch housing to approx 110 C using a hot air gun Knock the clutch housing against a woo den block so that the bearing falls out Check the clutch drum with regard to wear and damage Check the clutch drum with regard to wear and damage Th...

Page 38: ...e circlip G 3 Slide the clutch drum into the ball bearing 4 Screw the drive axle tightly onto the clutch drum Fit the clutch drum to the drive axle NOTE There should be no signs of grease in the clamping joint for the shaft and clutch cover Clean the surfaces using a degreasing agent Fit the clutch cover on the shaft 5 Lubricate the drive axle with grease and slide it on the shaft 6 Screw the clut...

Page 39: ...5 37 5 Angle gear Angle gear Contents Dismantling ________________________________ 38 Assembly__________________________________ 39 Shaft _____________________________________ 40 ...

Page 40: ...Remove the cutting equipment and guard Remove the splash guard Remove the screws holding the plate D and the bevel gear Remove the angle gear from the shaft Dismantling First remove the cutting equipment saw blade trimmer etc Remove the screw A and lift off the splash guard B Remove both screws C and lift off the plate D Remove the angle gear from the shaft Remove the circlip and plate washer on t...

Page 41: ...gear in the reverse order as set out for dismantling Fit the bearings on their respective axles It is easier if the bearings are heated to approx 100 C NOTE Do not forget the circlip holding the bearing on the input axle Make sure the bearings bottom in their seats Heat the gearbox to approx 150 C and first lift the output axle in position and then the input axle Make sure the bearings bottom in t...

Page 42: ...h grease no 503 80 17 01 when assembling Shaft Prise away the plastic sleeve A and the O ring B using a knife When fitting a new O ring must be used To avoid damage from the sharp edges of the slits in the gear housing the following assembly procedure is recommended 1 Place the plastic sleeve A in position in the gear housing 2 Slide the O ring B onto the plastic sleeve 3 Slide the shaft into posi...

Page 43: ...____ 42 Decompression valve ________________________ 43 Cleaning inspection _________________________ 43 Assembly _________________________________ 44 Analysis and actions _________________________ 45 Service tips ________________________________ 49 Wear tolerances ____________________________ 49 ...

Page 44: ...remove the cylinder Starter cylinder cover muffler guard muffler spark plug flywheel start valve carburet tor with air filter and covers air supply valve See separate sections in the manual Remove the cable A from the cable duct and separate the contacts Pry out the plastic bushes B with fuel hoses in the direction of the arrow Then loosen the 4 bolts holding the cylinder Carefully remove the cyli...

Page 45: ...a friction lining against the valve head when grinding Cleaning inspection After dismantling clean the individual components 1 Scrape carbon deposits from the top of the piston 2 Scrape carbon deposits from the cylinder s combustion chamber 3 Scrape carbon deposits from the cylinder s exhaust port 4 Wash all the components 5 Inspect the different components for damage and wear Check the piston and...

Page 46: ...emble the carburettor and the other parts in the reverse order as set out for dismantling Assembly Lubricate the gudgeon pin s needle bear ing with a few drops of engine oil and fit the piston Assembly Lubricate the gudgeon pin s needle bear ing with a few drops of engine oil Direct the arrow on the top of the piston towards the exhaust port Press in the gudgeon pin and fit the circlip NOTE Place ...

Page 47: ...l hose Leaking inlet gaskets Cracked distance piece or inlet manifold Air leakage in engine body Leaking crankshaft seals Leaking cylinder and crankcase gaskets Poor maintenance Dirty cooling fins on the cylinder Blocked air intake on the starter Blocked spark arrestor mesh in the muffler For the best results we recommend Husqvarna two stroke oil or ready mixed fuel that is specially developed for...

Page 48: ... the wear and can be caught in the port causing serious piston damage Action Change the fuel Cause Wrong type of two stroke oil or petrol Incorrect oil mixture in the petrol Incorrect carburettor setting Piston scoring caused by heavy carbon deposits Too heavy carbon depositing can cause damage similar to that caused by insufficient lubrication However the piston skirt has a darker colour caused b...

Page 49: ...ring failure Failure of the crankshaft bearing or on the connecting rod bearing is usually caused by a too high engine speed resulting in the bearing being overloaded or overheating This in turn can cause the bearing rollers or ball to glide instead of rotate which can cause the roller or ball retainer to break The broken debris can be trapped between the piston and cylinder wall damaging the pist...

Page 50: ...ter carefully for holes and damage after cleaning Replace the filter if necessary Clean more carefully and use the right cleaning agent such as tepid soapy water Change the filter Fit the filter correctly Fit a new air filter Larger softer particles that penetrate into the engine cause damage to the piston skirt under the piston ring as the illustration shows Cause Air filter incorrectly fitted Ai...

Page 51: ...groove Bolts much too tight in the aluminium material Action In severe cases replace the cylinder Repair the threads using Heli Coil Polish the damaged area using a fine grade emery cloth so that the coating of aluminium disappears With deep seizure score marks the piston and cylinder should be replaced Replace the cylinder and piston Carefully polish the damaged area using a fine file of fine gra...

Page 52: ...6 50 Cylinder and piston ...

Page 53: ... 7 Crankshaft and crankcase Contents Dismantling ________________________________ 52 Inspecting the crankshaft______________________ 53 Assembly _________________________________ 54 Crankshaft and crankcase ...

Page 54: ... as a scavenging pump for the fuel air mixture when this is sucked from the carburettor and is forced into the cylinder s combustion chamber The crankcase must be perfectly sealed so as not to affect this pump function There cannot be any leakage from the crankshaft between the crankcase halves or between the crank case and the cylinder Always replace the sealing rings and gaskets when servicing t...

Page 55: ... 150 C using a hot air gun Knock the halves against a wooden block so that the bearings fall out of their seats Remove the gaskets with a suitable punch Scrape off any gasket residue from the cylinder base plane and from the crankcase s contact face Inspecting the crankshaft Check that there is no play on the coppers around the crank disks Inspecting the crankshaft Check that there is no play on t...

Page 56: ...uter ring If movement is jerky the bearing track is probably damaged If so replace the bearing Also check that the gap is not too great Inspect the sealing rings The seal edge shall be sharp or slightly ground Inspect the small end of the connecting rod Inspect the small end of the connecting rod If seizure marks or discolouration are found in the bearing track the crankshaft must be replaced Asse...

Page 57: ...nkcase half of the magnet side into place over the crankshaft Tighten the 5 crankcase screws crosswise 1 5 Check that the crankshaft can rotate easily If not hit the axle spindles sharply a few times with a rubber hammer so that the tension in the crankshaft disappears Lubricate the axle spindles with engine oil and press the sealing rings until level with the crankcase using a suitable punch or t...

Page 58: ...7 56 Crankshaft and crankcase ...

Page 59: ...____________ 58 Fuel system ________________________________ 58 Centrifugal clutch____________________________ 58 Angle gear _________________________________ 59 Cylinder and piston __________________________ 59 Crankshaft and crankcase_____________________ 59 Workshop equipment_________________________ 59 Tools ...

Page 60: ...0 530 03 55 60 531 03 06 23 502 50 18 01 502 51 94 01 502 50 18 01 502 71 14 01 502 21 58 01 521 54 83 01 521 54 83 01 502 50 18 01 502 50 64 01 0 3 502 50 83 01 502 52 16 02 505 69 85 70 502 51 91 01 List of tools Electrical system Fuel system Centrifugal clutch Starter Fuel system ...

Page 61: ...5 69 85 70 505 38 17 05 503 80 17 01 502 50 70 01 505 38 17 09 502 50 18 01 502 50 65 01 544 13 05 01 544 13 08 01 544 13 09 01 544 13 10 01 544 34 87 01 502 54 11 01 List of tools Angle gear Cylinder and piston Crankshaft and crankcase Workshop equipment Workshop equipment ...

Page 62: ...8 60 List of tools ...

Page 63: ..._________ 62 Ignition system______________________________ 62 Carburettor ________________________________ 62 Clutch ____________________________________ 62 Driving ____________________________________ 62 Dimensions ________________________________ 62 Technical Data ...

Page 64: ...s Carburettor Manufacturer Walbro WTE WTE WTE WTE Walbro air supply valve Yes Yes Yes Yes Basic setting H jet 1 1 1 1 1 1 1 1 Basic setting L jet 0 9 0 9 0 9 0 9 Idle speed rpm 2 700 2 700 2 700 2 700 Air filter type Nylon Nylon Paper Paper Throttle control type Thumb Thumb Forefinger Forefinger throttle throttle throttle throttle Clutch 3 shoe clutch Diameter mm 69 69 69 69 Engage speed rpm 3 700...

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