Stiga TRE 224 Workshop Manual Download

Page: 51 / 55

Release 00 - 03/2018

Engine TRE 224

page 51

Workshop Manual

15. ENGINE BLOCK - Overhauling internal parts

Tightening torques

Union screws under carter and sump

24-32 Nm

12 Counterweight governor fixing screw

5-7 Nm

18 Fixing screws lower connecting rod cap

13-15 Nm

Technical information

Oil sump capacity

0,5 litres

Diameter seat of camshaft

13,92 mm

Diameter aspiration cam

27,30 mm

Diameter discharge cam

27,45 mm

Maximum segments gap in the cylinder

1,0 mm

Max. compression ring axial gap

0,15 mm

Minimum gudgeon pin diameter

17,95 mm

Max. gudgeon pin housing diameter on piston

18,05 mm

Max. connecting rod diameter

gudgeon pin side

18,07 mm

crank side

30,07 mm

Diam. connecting rod’s pin on engine shaft

29,92 mm

Verify the engine shaft extremes

0,10 mm

Special equipment

21 Piston ring removal expander
33 Piston ring compressing tool

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INDEX

Summary of Contents for TRE 224

Page 1: ...s or duplication reproduction or translation even partial of the texts in this document may be made without explicit authorization IMPORTANT NOTICE The information contained herein is intended for Service Operations and professionals only able to competently perform the operations described herein using the appropriate equipment in order to safeguard se curity and performance of the machine The ma...

Page 2: ......

Page 3: ...Identification 9 3 2 Technical data 9 3 3 Adjustments 9 3 4 Expendable materials 9 3 5 Use limits 9 3 6 Tightening torques 10 3 7 Table of Tightening torques 11 3 8 Identification of engine units 12 4 ENGINE TUNING AND TESTING 13 4 1 Operating guidelines 13 4 2 Engine tuning program 13 4 3 Functional test 14 5 SUPPLY SYSTEM 15 6 STARTING SYSTEM 16 6 1 Removing the starter motor 16 6 2 Disassembly ...

Page 4: ...ernal operations 34 14 1 Checking the compression 34 14 2 Adjusting the valve clearance 35 14 3 Dismantling and cleaning the cylinder head 36 14 4 Overhauling the cylinder head and valves 37 14 5 Dismantling and replacing the magneto flywheel 39 14 6 Alternator removal and replacement 40 14 7 Checking the oil breather 40 14 8 Replacing the upper compression ring of the engine shaft flywheel side 4...

Page 5: ...t attached in the proper places 6 Assemble the cover 4 5 5 1 1 1 A Motor typ for which the page is valid B Reference to the chapter and the argument with the relative numbering C Presence of previous or following chapters from the present chapter D Issue date or possible audit E Audit number F Page progressive numbering Certain symbols are used in the manual highlighting particularly important inf...

Page 6: ... and made available to the manufacturer together with the replaced parts in case clients should make further complaints 1 3 Fault notification The manufacturer should be informed of all faults that recur frequently this allows it to carefully exa mine the problem and make corrections on the production line Similarly the manufacturer shall report any faults traced on its engines indicating the best...

Page 7: ...ctive damaged or missing guards and covers replace illegible labels do not carry out operations or modifications on the lawnmower or on the engine that could af fect their performance or lead to an improper or different use from the one for which it has been designed and approved warn the customer that the failure to comply with the above points automatically voids the war ranty and the responsibi...

Page 8: ...nectors or cabling clamps Replace those that are damaged 2 Observe the instructions and warnings contained in the present manual and on the safety plates on the engine Inappropriate functioning and maintenance can result in serious injury or even death 3 Ventilation of closed areas In the event that it is necessary to start the engine in a closed environment or if petrol or cleaning oil is being u...

Page 9: ...et valve head rim thicknesse 0 5 mm Minimum exhaust valve head rim thickness 0 5 mm Valve seat depth 2 0 mm Minimum valve spring length 33 0 mm Maximum gap between ends of cylinder rings 1 0 mm Max axial gap for compression rings 0 15 mm Minimum gudgeon pin diameter 17 95 mm Max gudgeon pin piston seat diameter 18 05 mm Max connecting rod diameter gudgeon pin side 18 07 mm crankside 30 07 mm Diam ...

Page 10: ...ne TRE 224 Workshop Manual 3 TECHNICAL DATA AND SPECIFICATIONS 3 6 Tightening torques 8 12 Nm 30 36 Nm 27 30 Nm 24 32 Nm 8 12 Nm 8 12 Nm 13 15 Nm 8 10 Nm 5 8 Nm 8 10 Nm 8 12 Nm 5 7 Nm 8 12 Nm 5 7 Nm 8 12 Nm 80 90 Nm 4 6 Nm BACK INDEX ...

Page 11: ...ing screw AUTO CHOKE 5 7 Nm 11 14 Spark plug tightening torque 27 30 Nm 11 14 Coil fixing screw 8 12 Nm 11 14 Coil fixing stud 8 12 Nm 13 Muffler fixing nuts 8 12 Nm 14 Valve cover fixing screws 8 12 Nm 14 Fixing head screws 30 36 Nm 14 Attachment bolt flywheel 80 90 Nm 14 Fixing screws generator 8 12 Nm 14 Pad plate screw 4 6 Nm 15 Union screws under carter and sump 24 32 Nm 15 Counterweight gove...

Page 12: ...manual has subdivided maintenance operations into different sections each of which refers to an engine component unit as indicated in the diagrams below 3 TECHNICAL DATA AND SPECIFICATIONS Exhaust system Engine block Starting system Carburettor Carburation control Air intake Ignition AUTO CHOKE Starting system BACK INDEX ...

Page 13: ...iency in accordance with two intervention lines Tuning the engine whenever possible Recommending the client a routine maintenan ce program at set intervals e g at the end of the season or before a long period of inactivity 4 2 Engine tuning program As part of general engine tuning or any intervention on the machine it is recommended that the Service Centre performs a series of operations aimed at ...

Page 14: ...ve refuelled the tank with new petrol check the seal of the tank the cap and the car burettor pipe b Hot and cold starting test The engine is equipped with intelligent starter sy stem AUTO CHOKE with the throttle in the SLOW position perform some cold and hot starts to make sure they happen regularly c Check the engine rpm When the engine is hot enough check the engine speed with the throttle cont...

Page 15: ...oat chamber is caused by gravity and the volume of petrol taken from the tank as the engine runs is compensated by a breather pipe in the cap See the relevant section 16 for advice on resolving problems due to the malfunctioning of the petrol supply system WARNING All interventions on the supply system must be performed in safe conditions therefore do not smoke work in a ventilated environment awa...

Page 16: ...or advice on resolving problems due to the malfunctioning of the star ting system 6 STARTING SYSTEM 3 2 6 1 Removing the starter motor 1 Remove the cover by unscrewing the three nuts 1 2 Disconnect the connector 2 from the wiring 3 Disconnect the live cable 3 and the earth cable 4 4 Remove the two screws 5 and remove the motor 5 To assemble repeat the operation in reverse When attaching the connec...

Page 17: ... compressed air spray with lubricant and repeatedly move the pinion when the movement becomes smooth clean with compressed air spray again with lubricant Avoid using grease or oil as it causes dirt to accu mulate If the motor becomes noisy it should be replaced 6 1 4 Remove the pinion assembly by undoing the screws 8 and check the condition of the gears Replace the pinion assembly if there is any ...

Page 18: ...ft hand side of the engine and can be inspected without having to remove other parts The filter assembly is to be removed only to accede the carburettor 7 INTAKE SYSTEM 7 1 Maintenance of filtering element WARNING Never run the engine without air filter The engine would certainly be dama ged 1 Clean the area around the filter cover 1 by blowing it with compressed air 2 Remove the cover plate 1 by ...

Page 19: ...with compressed air from the interior side to remove dust and product residues IMPORTANT For the cartridge cleaning don t use water petrol detergtent 6 Wash the preﬁlter with water and detergent and let it air dry IMPORTANT the preﬁleter MUST NOT be oi led 7 Reﬁt the preﬁlter 5 on the cartridge 8 With a jet of compressed air clean inside the seat 6 of the ﬁlter by removing dust and remains of gras...

Page 20: ...page 20 Release 00 03 2018 Engine TRE 224 Workshop Manual 7 INTAKE SYSTEM 9 Reassemble in their seats the filter element 3 and its cover plate 1 by turning the dedicated knob 2 3 2 1 BACK INDEX ...

Page 21: ...on the tank and supply system must be carried out in safe conditions so do not smoke always empty the tank if petrol is not strictly necessary for the operation to be carried out work in a ventilated environment away from naked flames or unprotected sources of heat collect petrol in a suitable container with a cap using a funnel and avoid spilling it on the work bench remove all traces of spilt pe...

Page 22: ... Using pliers remove the tie rod 8 of the AUTO CHOKE lever and remove the carburettor 9 and the gaskets 10 which will be replaced when re assembling 5 Loosen the central screw 11 fastening the flo at chamber 12 remove the relative gasket 13 and carefully collect all the petrol left in the float chamber 6 Pull out the pin 14 dismount the float 15 and remove the gasket 16 8 6 9 12 11 14 15 16 7 10 1...

Page 23: ...following the previous points 6 5 and 4 in reverse order remembering that It is always advisable to replace the wa sher 16 and the gasket 13 of the float chamber the float 15 must oscillate freely on the pin 14 the jet 17 should never be modified or replaced with others even if they seem to have the same specifications the AUTO CHOKE 20 must open and close re gularly the float chamber drain screw ...

Page 24: ...e s minimum speed must be between 1800 150 rpm 3 Turn the screw 23 until you achieve a stable minimum speed within the above values 8 4 Adjusting maximum speed NOTE This operation is carried out by adju sting the governor system 9 2 8 5 Adjusting the carburation NOTE The carburation is set in the factory and does not normally need changing In the event of irregular functioning clean the carburetto...

Page 25: ...n with the spring that would keep it open the balance between the spring loading and the thrust of the counterweights on the control lever modifies the butterfly opening and adapts the flow of fuel to the engine so that the revolution speed is kept constant with engine load changes See the relevant section 16 for advice on resolving problems related to the governor system 9 1 Adjusting of accelera...

Page 26: ...sh the correct value of the maximum turn system NOTE The engine s maximum speed must be between 2800 100 rpm if you do not read this value proceed as follows 5 Check that the spring 8 is intact and positioned at the attachment point furthest from the fulcrum of the control lever that the wire 9 and the relative spring 10 are intact and not deformed that the moving levers 11 are not bent or defor m...

Page 27: ...ockwise to the end of its stroke and then lock the nut 13 9 3 Replacing the lever support 1 Position the accelerator lever to minimum SLOW position 2 Remove the carburettor 8 1 3 Disconnect the accelerator cable 3 and the spring 8 4 Undo the two screws 15 securing the support 16 to the engine 5 Perform the above operations in reverse order when assembling 6 Refit the carburettor 8 1 7 Adjust the m...

Page 28: ... to the adjusting pin of the second throttle valve See the relevant section 16 for advice on resolving problems related to the AUTO CHOKE system 10 AUTO CHOKE SYSTEM 10 1 Replacing of the AUTO CHOKE system 1 Remove the cover 2 Remove the filtering unit 3 Unfasten the two screws 1 4 Using pliers pull the lever 2 connecting the AUTO CHOKE system to the carburettor 5 Perform the above operations in r...

Page 29: ...r 3 to the spark plug cap 4 and to earth on the engine 5 Activate the starter and see in the instrument if the spark jumps 3 If the test has a positive result clean the electro des 2 with compressed air and adjust the distance to 0 6 0 8 mm Remount the spark plug and tighten it to the specified levels Unless otherwise required proceed to verify system components as indicated in section 11 2 0 6 0 ...

Page 30: ...the screw 9 and the stud 10 which secure the coil 7 Rotate the flywheel 11 so as to bring the magnetic inserts next to the poles of the core of the coil 5 Insert a 0 35 mm thickness gauge 12 between the flywheel 11 and the coil poles 7 push the coil until the poles come in contact with the thickness gauge and secure screw 9 and stud 10 with the flywheel locked the airgap must be between 0 35 and 0...

Page 31: ...ct the faston of the earth cable 6 3 Undo the screw 9 and the stud 10 and remove the coil 7 4 Mount the new coil and regulate the air gap according to the procedure indicated in points 4 and 5 in section 11 2 5 Connect the faston of the earth cable 6 6 Refit the starter assembly 6 1 Tightening torques 1 Spark plug tightening torque 27 30 Nm 9 Coil fixing screw 8 12 Nm 10 Coil fixing stud 8 12 Nm T...

Page 32: ...00 03 2018 Engine TRE 224 Workshop Manual 12 TURNING OFF AND STOPPING THE ENGINE For maintenance operations relating to this section refer to the manual speciﬁc to the machine on which the engine is mounted BACK INDEX ...

Page 33: ...crew the two screws 1 securing the AUTO CHOKE to the silencer separating it from the exhaust unit 2 Remove the two nuts 2 that fix the muffler 3 3 Take out the muffler 3 and the heatproof baffle 4 4 On assembly thoroughly clean the cylinder contact surface removing all deposits or fragments on the heat proof baffle always replace damaged mufflers always replace the heatproof baffle 4 if it is brok...

Page 34: ...nd connect the supply pipe to a compressed air socket with a pressure of approximately 4 bar 58 psi 4 On opening the air tap 4 the manometer gau ge on the engine side should position itself in the green zone and remain there for about 30 seconds If the gauge falls rapidly it means that the com pression is poor NOTE Lack of compression could be due to incorrect valve clearance 14 2 cylinder head lo...

Page 35: ... the TDC Top Dead Centre of the compression stroke so that both valves are closed 4 Use a feeler gauge 8 to check the gap betwe en the rocker arm and the tip of the valve stem the gauge should pass between without forcing and without a further gap 5 The gap is adjusted by slackening off the nut 9 and suitably adjusting the register nut 10 to obtain the following values Inlet IN YI 0 10 0 15 Exhaus...

Page 36: ...er sur faces 16 8 Carefully clean the inside of the combustion chamber and remove possible deposits from the valve seats 9 Turn the flywheel by hand to move the piston and check the internal surface of the cylinder 16 10 When mounting the gasket 15 must always be replaced Remount the cylinder head 14 screwing the six screws 13 without fully tightening then tighten them to the given torque values u...

Page 37: ... EX YE exhaust on the valve head 3 Use an emery cloth to remove all incrustations from the valve head and check the thickness of the rim A the valve must be replaced if the margin A is less than 0 5 mm inlet IN YI or 0 5 mm exhaust EX YE or if it shows signs of burning 4 Check the diameter of stem B in several points and replace the valve if it is less than the following even if only in one point ...

Page 38: ...e seat and rim 10 Check the free length of the spring 23 and replace the spring of it is less than 33 0 mm 11 When mounting carefully clean the valve guides and housings of any foreign body apply a film of oil on the valve stems before inser ting them in their respective housings ensure the correct position of the inlet valve and the exhaust valve marked respectively with YI and YE on the valve he...

Page 39: ...stud 29 and re move the electronic coil 27 4 Using a suitable extraction tool remove the flywheel 30 as indicated in the diagram Ensure that the engine shaft key is retained 5 While assembling the fly wheel check the inte grity of the key 31 and replace it if it is deformed mount the plate 26 and the fan 25 Tighten the nut to the specified torque 24 6 Refit the coil 27 tightening the screw 28 and ...

Page 40: ...e In case of malfunction replace the alternator 14 7 Checking the oil breather 1 Unscrew the screw 33 fixing the closing plate 34 2 Check that the pad 35 is not damaged or deformed Replace it if necessary If necessary wash with water and neutral deter gents 3 If necessary replace the cork gasket 36 and reassemble the closing plate 34 tightening the screw with the indicated torque 32 32 33 36 35 34...

Page 41: ... damage the sealing lip 5 Refit the key 31 and the magneto flywheel 14 5 14 9 Replacing the lower compression ring of the engine shaft sump side NOTE For engine removal operations you should consult the manual specific to the machine on which the engine itself is mounted NOTE Before executing this operation di scharge all the oil from the bowl and rotate 180 the motor 1 Take out the spline key 40 ...

Page 42: ...xing screw 8 12 Nm 29 Coil fixing stud 8 12 Nm 32 Fixing screws generator 8 12Nm 33 Pad plate screw 4 6 Nm Technical information Compression Min 4 bar Inlet valve clearance 0 10 0 15 mm Exhaust valve clearance 0 15 0 20 mm Minimum inlet valve stem diameter 5 32 mm Minimum exhaust valve stem diameter 5 27 mm Min inlet valve head rim thickness 0 5 mm Min exhaust valve head rim thickness 0 5 mm Valve...

Page 43: ...p by unscrewing the seven screws 1 4 verify the phasing between the engine shaft and the camshaft If necessary re set the phasing referring to the indications provided 5 On assembly follow the steps described in re verse and always replace the gasket 2 between cover and sump ensure that the two centring pins 3 are correctly inserted always replace the compression ring from the sump side 14 8 ensur...

Page 44: ...r The value must not be lower than 27 30 mm IN YI and 27 45 EX YE 6 Check the regular movement of the pressure reducer 6 and the efficiency of the spring 7 the whole group must always be replaced in the case of breakage or irregular operation of the pressure reducer 7 Check that the irregolar centrifugal 8 that are not present ruptures of the lubrication pallets 8 Turn the governor s gears quickly...

Page 45: ...replaced 10 Before fitting the camshaft ensure that the two tappets 13 are correctly housed in their seats 11 When refitting the camshaft maximum care must be taken to match up the two references 14 and 15 punched on the gears so as to ensure correct distribution phasing 12 During assembly refer to the operations in section 15 1 always remembering to replace the washer 2 between the sump and the h...

Page 46: ...e cap 16 of connecting rod 17 fixed with two screws 18 take note of any refe rence marks for refitting 5 Push the connecting rod 17 so as to cause the piston 19 to come out of the cylinder 20 6 Use the special expanding tool 21 to re move the two compression rings and the oil scraper ring from the piston 19 7 Carefully remove all carbon deposits from the compression rings the inside of the cylinde...

Page 47: ...new ring and measure the residual space with a feeler gauge 24 The piston must be replaced if it is greater than 0 15 mm in the two compression ring housings 11 Use a screwdriver to remove the clamping ring 25 and remove the gudgeon pin 26 from the piston 19 12 Check the diameter of the gudgeon pin 26 in several places and replace it if it is less than 17 95 mm even at a single point 15 ENGINE BLO...

Page 48: ...ues are greater than B 18 07 mm on the gudgeon pin side C 30 07 mm on the crank side If the connecting rod is outside measurement tole rances or has small scratches or marks it is neces sary to replace it 15 Remove the engine shaft 27 checking the diameter of the connecting rod pin with a digital gauge The value must not be less than 29 92 mm or the engine shaft will have to be replaced NOTE In th...

Page 49: ...ld be dangerous when the machine is used 17 To reassemble the segments on the piston per form sequentially Mount the oil wiper 30 composed of three rings Assemble the rounded edge segment 31 with the rounded edge facing downwards Assemble the live edge segment 32 NOTE The two segments 31 and 32 must be oriented with the lights not aligned betwe en them 18 Fit the connecting rod 17 the gudgeon pin ...

Page 50: ...ter having fixed the connecting rod cap take the greatest care to ensure that the two position references 14 and 15 punched on the engine shaft and camshaft gears coincide ensuring the correct distribution phasing 23 Close the carter and fix the screws 1 to the indicated couple 15 1 24 Whenever the engine shaft is dismantled and refitted it is always necessary to replace the sealing ring on the fl...

Page 51: ... seat of camshaft 13 92 mm Diameter aspiration cam 27 30 mm Diameter discharge cam 27 45 mm Maximum segments gap in the cylinder 1 0 mm Max compression ring axial gap 0 15 mm Minimum gudgeon pin diameter 17 95 mm Max gudgeon pin housing diameter on piston 18 05 mm Max connecting rod diameter gudgeon pin side 18 07 mm crank side 30 07 mm Diam connecting rod s pin on engine shaft 29 92 mm Verify the...

Page 52: ...park plug Blocked air filter Execute the filter cleaning 7 1 Fouling in the combustion chamber Dismount the cylinder head and re move fouling 14 3 Insufficient pressure Check tightness of cylinder head screws replace washer if necessary Check wear and tear of the piston rings 15 3 AUTO CHOKE malfunction AUTO CHOKE check and or replace ment 10 1 No power supply to battery Check the alternator 14 6 ...

Page 53: ... plug connections Perform spark test 11 1 or re place spark plug AUTO CHOKE malfunction AUTO CHOKE check and or replace ment 10 1 The engine overreved Governor blocked due to breakage of centrifugal assembly or breakage of external governor springs It is possible that the governor is dirty Check the entire governor system 9 and 15 The engine judders Engine screws loose Tighten the screws Engine ti...

Page 54: ... devices fitted to the machine Check all the electrical connections and the efficiency of the control de vices fitted to the machine Electrical insufficiency of the starter motor Replace the starter motor The starter motor turns but cannot start the engine Battery insufficiently charged Check and recharge the battery Mechanical inefficiency of the starter motor Dismantle the motor and clean the pi...

Page 55: ...Release 00 03 2018 Engine TRE 224 page 55 Workshop Manual BACK INDEX ...

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