Zenoah GZ4350 Workshop Manual Download

Page: 60 / 62

- English

Troubleshooting

Acceleration och retardation

Does not

accelerate

Engine stalls

when throttle

released

Over rich

acceleration

Adjust L screw

Adjust H screw

Blocked air filter

Blocked fuel tank vent

Blocked fuel filter

Fuel line blocked

Loose or damaged fuel hose

Impulse channel blocked

Loose cover on carburettor pump

side

Faulty pump diaphragm

Leaking air intake hose (rubber)

Loose carburettor mounting bolts

Needle valve set too low

Metering system incorrectly

assembled

Needle valve assembly sticking

Faulty diffuser jets

Blocked silencer

Adjust L screw

Adjust H screw

Faulty pump diaphragm

Needle valve set too high

Needle valve assembly sticking

Faulty diffuser jets

Adjust L screw

Adjust H screw

Blocked air filter

Faulty pump diaphragm

Faulty diffuser jets

8.2 Troubleshooting methods

In addition to the faults described in the above

table, trouble shooting can be carried out on

specific components or sub-systems of the chain

saw. The various procedures are described in

the relevant chapters, see the contents page, as

follows:

•  Checking the operation of the chain brake
•  Measuring the resistance of the stop plate
•  Pressure testing the carburettor
•  Pressure testing the decompression valve
•  Pressure testing the cylinder

High rpm

Will not run at

full throttle

Low power

Will not “four-

stroke”

Adjust H screw

Blocked air filter

Blocked fuel tank vent

Blocked fuel filter

Fuel line blocked

Loose or damaged fuel hose

Impulse channel leaking

Impulse channel blocked

Loose cover on carburettor pump

side

Faulty pump diaphragm

Leaking air intake hose (rubber)

Loose carburettor mounting bolts

Needle valve set too low

Metering system damaged

Metering system incorrectly

assembled

Leaking control diaphragm/cover

plate

Needle valve assembly sticking

Blocked silencer

Adjust H screw

Blocked fuel tank vent

Blocked fuel filter

Impulse channel leaking

Impulse channel blocked

Loose cover on carburettor pump

side

Faulty pump diaphragm

Blocked air filter

Needle valve assembly sticking

Leak in metering system (air or

fuel)

Metering system incorrectly

assembled

Loose diaphragm rivet

Hole in diaphragm

Leaking control diaphragm/cover

plate

Blocked fuel tank vent

Blocked fuel filter

Fuel line blocked

Loose or damaged fuel hose

Impulse channel leaking

Impulse channel blocked

Loose cover on carburettor pump

side

Faulty pump diaphragm

Leaking air intake hose (rubber)

Loose carburettor mounting bolts

Needle valve set too low

Leak in metering system (air or fuel)

Metering unit incorrectly assembled

Loose diaphragm rivet

Hole in diaphragm

Leaking control diaphragm/cover

plate

Summary of Contents for GZ4350

Page 1: ...Workshop Manual English GZ4350...

Page 2: ......

Page 3: ...6 Technical data 9 Service tools 11 Service data 13 Safety equipment 15 Repair instructions 23 Troubleshooting 57 Contents Husqvarna AB has a policy of continuous product development and therefore re...

Page 4: ...tructions 7 General 7 General Instructions 8 Modifications 7 Safety 7 Special Instructions 8 Structure 7 Target group 7 Tools 7 M Muffler 19 Assembling the muffler 20 Cleaning and inspection 19 Disman...

Page 5: ...English 4 Index...

Page 6: ...and safety regulations Contents 2 1 General 6 2 2 Safety 6 2 3 Target group 6 2 4 Modifications 6 2 5 Tools 6 2 6 Structure 6 2 7 Numbering 6 2 8 General instructions 7 2 9 Special instructions 7 2 1...

Page 7: ...Tools Special tools are required for some stages All service tools are listed in the Workshop Manual Usage is made apparent in each section Always use Husqvarna s original Spare parts Service tools Ac...

Page 8: ...art the chain saw unless the guide bar saw chain and clutch cover chain brake are fitted otherwise the clutch may loosen and cause per sonal injury Insufficient saw chain lubrication can result in saw...

Page 9: ...e embedded on the chain saw Choke Lever Refuelling Stop switch Chain oil fill Chain brake Primer bulb Adjusting the oil pump Heated handles 2 11 Symbols in the Workshop Manual This symbol warns of per...

Page 10: ...95 9 600 Electrode gap Ignition system Air gap Carburettor type mm inch mm inch GZ4350 0 65 0 025 IKEDA UK 09701 0 4 0 016 Walbro HD 54B Usable cutting length Chain speed at 133 of Chain pitch Drive l...

Page 11: ...pm GZ4350 4100 250 NGK CMR7H Adjustable Volume fuel tank Capacity oil pump at Volume oil tank Litre US pint 9 000 rpm Litre US pint ml min GZ4350 0 42 0 87 3 13 0 27 0 57 Technical data Weight without...

Page 12: ...11 English 11 12 9 4 Service tools Service tools 4 3 8 1 2 7 10 5 6 13 14 15 16 17...

Page 13: ...71 14 01 15 Rubber wedge outlet Pressure testing 502 54 11 02 16 Bearing oil seal kit MAG side 584 14 05 01 17 Bearing oil seal kit PTO side 584 14 05 02 18 Pressure vacuum gauge Pressure testing 531...

Page 14: ...umbers by bolted components represent the tightening torque in Nm Lubricate with two stroke oil Lubricate with grease Apply thread lock Three bond 1322 or Loctite 262 Apply thread lock Three bond 1342...

Page 15: ...English 14 Service data...

Page 16: ...g the muffler 18 6 4 Assembling the muffler 19 6 5 Replacing the chain catcher 19 6 6 Dismantling the stop switch 19 6 7 Assembling the stop switch 19 6 8 Resistance test stop function 20 6 9 Dismantl...

Page 17: ...show signs of other defects Always use original spare parts Measure the thickness of the chain brake band It must not be less than 0 6 mm in any place See figure 4 Lubricate the knee joint with grease...

Page 18: ...5 2 Compress the spring with a wide screwdriver or special tool 513 63 70 01 and press it down with your thumb see figure 6 3 Fit the two covers using 0 7 1 5 Nm tightening torque see figure 7 WARNING...

Page 19: ...muffler until it has cooled Risk of burns 6 3 Dismantling the muffler 1 Remove the cylinder cover muffler and gasket See figure 11 2 If the muffler is fitted with a spark arrestor mesh this is remove...

Page 20: ...onnect the cables Cleaning and inspection Clean and check the power switch carefully Parts must be replaced if cracked or show signs of other defects Always use original spare parts Fig 13 Fig 14 6 4...

Page 21: ...the stop switch as outlined in 6 6 Dis mantling the stop switch 2 Clean the contact areas 3 Test the resistance by connecting a multimeter to the stop switch See figure 15 The resistance should be as...

Page 22: ...kout throttle trigger and spring 1 Loosen the screw on the rear handle Remove the handle cover See figure 16 Cleaning and inspection Carefully clean and check all parts See figure 19 Parts must be rep...

Page 23: ...tted as outlined in figure 20 Safety equipment Fig 20 Fig 21 Fig 22 2 Fit the throttle rod on the throttle trigger Fit the throttle trigger s pin using a punch See figure 21 3 Fit the throttle trigger...

Page 24: ...g the centrifugal clutch 30 7 11 Assembling the centrifugal clutch 31 7 12 Dismantling the oil pump and screen 31 7 13 Assembling the oil pump and screen 31 7 14 Dismantling the intake system 32 7 15...

Page 25: ...an the parts and check The starter cord That the starter pawls on the flywheel are intact i e that they spring back to the centre and move easily To lubricate the return spring using light oil 7 Repai...

Page 26: ...ole in the starter housing and starter handle and tie a double knot on the cord Wind approx 3 turns of the starter cord on the starter pulley Turn the starter pulley until it latches into the correct...

Page 27: ...ismantling the starter chapter 7 5 Starter assembly 1 Position the starter against the crankcase and tighten the screws at a tightening torque of 2 5 3 9 Nm see figure 8 Fig 8 7 6 Removing the cylinde...

Page 28: ...fly wheel See figure 11 4 Detach the ignition cable and loosen the screws See figure 12 Cleaning and inspection Clean all parts especially the tapers on the flywheel and shafts Check the flywheel for...

Page 29: ...the nut for the flywheel 3 Insert the plastic air gap tool at a thickness of 0 4 0 1 mm between the lugs on the ignition module and flywheel See figure 15 Turn the flywheel so that the magnets are pos...

Page 30: ...by meas uring them with slide callipers across the whole clutch hub If the thickness is below 60 mm the clutch must be replaced See figure 19 2 Remove the spark plug hat and the spark plug In sert the...

Page 31: ...he cylinder cover guide bar saw chain clutch cover 7 12 Dismantling the oil pump and screen 1 Empty and clean the saw chain oil tank Dismantle the centrifugal clutch as outlined in Dismantling the cen...

Page 32: ...e figure 22B 3 Fit the clutch See the Assembling the centrifugal clutch chapter 4 Fit the saw chain guide bar and clutch cover 5 Adjust the oil pump See Figure 23 WARNING Insufficient saw chain lubric...

Page 33: ...ntake flange C See figure 25 3 Fit the carburettor and the throttle rod as outlined in Assembling the carburettor 4 Fit the air filter the filter holder the cable from the intake flange holder 5 Fit t...

Page 34: ...e fuel s control functions are located in the metering unit A Here the correct fuel amount is adjusted for the current speed and power output See figure 26 Pump unit In the pump unit C fuel is pumped...

Page 35: ...n See figure 29 Full throttle mode In full throttle mode both valves are open and fuel is supplied through all three diffuser jets E F and G See figure 32 Part throttle mode In part throttle mode the...

Page 36: ...r filter 2 Remove the manifold See figure 33 Fig 34 Fig 35 Fig 33 3 Detach hose A B and C from the carburettor See figure 34 4 Unhook the choke and throttle rods See figure 34B 5 Remove the carburetto...

Page 37: ...ve screw P and needle valve M with lever arm Q shaft L and spring R See figure 36 Fig 37 8 Remove screw Z and remove gasket Y and dia phragm X See figure 37 9 Use a needle or similar device and carefu...

Page 38: ...ismantle throttle valve T and the High S and Low P jet screws valve Remove the shafts with lever arms and springs See figure 38 Cleaning and inspection Clean all units in clean petrol Use compressed a...

Page 39: ...figure 40 7 Fit gasket K the control membrane J and the pump cover H See figure 42 8 Carry out a pressure test See Pressure testing the carburettor Fig 41 Fig 42 Fig 40 5 Check using a ruler or the l...

Page 40: ...he check as follows 1 Connect pressure tester to the carburettor fuel inlet 2 Submerge the carburettor into a container with water See figure 43 3 Pump up the pressure to 20 kPa 4 No leakage is permit...

Page 41: ...it the pulse hose A the input hose B and the tank return hose C See figure 44 3 Fit the manifold See figure 45 4 Fit the choke and throttle rods to the carburettor See figure 45B 5 Fit the cylinder co...

Page 42: ...usting the carburettor involves adjusting the engine to the local conditions e g climate altitude fuel and type of 2 stroke oil The carburettor is equipped with three adjustment options L Low speed je...

Page 43: ...e again 4 Turn the L screw counterclockwise 0 5 of a turn 5 Adjust the T screw until the idling speed is 2 700 rpm Adjustment of the H needle 1 Adjust the H screw until the maximum engine speed at ful...

Page 44: ...bar starter and the cylinder cover Remove the rear handle cover 3 Detach hoses B and C Detach the throttle rod A See figure 46 4 Remove the handle bar Detach the handle heater Remove the chain catcher...

Page 45: ...oth sides See figures 48 49 Cleaning and inspection Clean and inspect all parts carefully If there are any cracks or other defects replace the damaged parts with new ones Always use original parts Ass...

Page 46: ...ter holder Assembling 1 Snap the primer bulb in place in the filter holder See figure 51 2 Fit the return and suction hose on the primer bulb 3 Fit the air filter and cylinder cover 7 21 Replacing the...

Page 47: ...nectors in the heating elements in the rear handle and the power switch s contact plate is the most common fault Troubleshoot as follows 1 Remove the screw holding the earth cables Remove the cover Se...

Page 48: ...ront handle s heating element 2 The multimeter reading should indicate between 1 8 and 2 4 Replace the front handle if you get another reading If the lead wire is open circuted or its covering materia...

Page 49: ...kcase opening 4 Remove the circlips and press out the gudgeon pin Remove the piston See figure 59 5 Remove the gudgeon pin bearing the needle bea ring using a pliers See figure 59 6 Replace with a new...

Page 50: ...ston to push the piston ring downward That the gudgeon pin bearing is intact That the intake bellows is intact Fig 61 Faults and causes See Figure 62 Score marks on the piston A 1 Leakage check not ca...

Page 51: ...rod Se figure 63 2 Attach the piston with the arrow facing the exhaust port Slide in the gudgeon pin and fit the circlips Note Use new circlips 3 Oil the piston with two stroke oil 4 Use piston assem...

Page 52: ...inder remove the muffler gasket Tighten the nuts for the muffler See figure 66 4 Screw the pressure test connection 503 84 40 03 in place Connect tool 531 03 06 23 to the nipple See figure 67 5 Pump t...

Page 53: ...e See Figure 68 3 Carefully pull the crankcase halves apart Two guide pins keep the crankcase halves together Remove the connecting rod and dispose of the gasket 4 If required remove the crankshaft be...

Page 54: ...ay is permitted See figures 69 2 That the big end bearing does not have any score marks or is discoloured on the sides 3 That the bearing surface for the gudgeon pin bearing does not have any score ma...

Page 55: ...2 Use special tool 584 14 05 01 as outligned in fig ure 72 to press the bearing into the crankcase 3 Use the same procedure for the press fitting of the bearing on the clutch side Note Use special too...

Page 56: ...te Fit the guide 513 70 59 01 to the crankshaft journal before the crankshaft is inserted The guide prevents the oil seal from getting dam aged Remove the guide afterwards See figure 74 9 Place the gu...

Page 57: ...l 502 50 30 22 and pull the crankshaft into the MAG side of the crankcase Se figure 76 11 Fix the six crankcase bolts Tighten them alternate ly Tightening torque 6 9 8 8 Nm See figure 77 12 Refit rema...

Page 58: ...57 English Troubleshooting 8 Troubleshooting Contents 8 1 Troubleshooting 58 8 2 Troubleshooting methods 59...

Page 59: ...rn throttle valve pivot Loose throttle valve screw Worn throttle valve Needle valve assembly sticking Leak in metering system air or fuel Metering system centre knob is worn Hole in diaphragm Leaking...

Page 60: ...compression valve Pressure testing the cylinder High rpm Will not run at full throttle Low power Will not four stroke Adjust H screw Blocked air filter Blocked fuel tank vent Blocked fuel filter Fuel...

Page 61: ......

Page 62: ...www zenoah com 115 96 21 26 3 4 2019...

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