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Release 00 - 02/2008

Engine WBE 0701-WBE 0704

pag. 25

Service manual

9. GOVERNOR SYSTEM OF THE CARBURETTOR

General information
The carburettor governor system

 uses a engine shaft linkage fitted on a support fixed to the left-hand side of 

the engine, completed by a counterweight device, driven by the camshaft, and thus sensitive to changes 

in the engine’s revolution pattern depending on load.

The force of the counterweights, transferred to the control lever, tends to shut the main carburettor butter-

fly, in opposition 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

 

 15]

 for advice on resolving problems related to the governor system.

9.1.  Adjusting of accelerator cable

1 - Loosen the screw (1) of the clamp (2) so that the 

cable casing () is free to move.

2 - Set the throttle control lever (4) to “CHOKE”.

3 - Move governor control lever (5) forward as far 

as possible and, by keeping it in this position, lock 

the casing () full tightening the screw (1) of the 

clamp (2).

CHOKE

2

1

4

5

1

2

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Summary of Contents for WBE 0701

Page 1: ...WBE 0701 WBE 0704...

Page 2: ...rences between the series of engines and the contents of this manual However the basic specifications and different operating procedures will remain the same by GLOBAL GARDEN PRODUCTS No use of the il...

Page 3: ...8 3 TECHNICAL DATA AND SPECIFICATIONS 9 3 1 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 torqu...

Page 4: ...4 Replacing the system for turning off and stopping the engine 33 12 EXHAUST SYSTEM 34 12 1 Removing and replacing the muffler 34 13 ENGINE BLOCK External operations 35 13 1 Checking the compression...

Page 5: ...any deposits inside 4 Keeping the hole 7 in the spigot closed pour about 100 cc of clean petrol into the tank and shake it vigorously to clean the inside 5 TANK AND SUPPLY 5 3 4 3 6 7 6 2 A Motor typ...

Page 6: ...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...

Page 7: ...e 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 improp...

Page 8: ...ors 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 mainte...

Page 9: ...for compression rings 0 15 mm Minimum gudgeon pin diameter 12 95 mm Max gudgeon pin piston seat diame ter 13 05 mm Max connec ting rod diame ter gudgeon pin side 13 07 mm crank side 26 07 mm 3 1 Iden...

Page 10: ...701 WBE 0704 Service manual 3 TECHNICAL DATA AND SPECIFICATIONS 3 6 Tightening torques 8 10 Nm 8 10 Nm 8 10 Nm 8 10 Nm 8 12 Nm 16 18 Nm 50 55 Nm 15 Nm 8 12 Nm 8 10 Nm 8 10 Nm 80 90 Nm 4 6 Nm 8 12 Nm 8...

Page 11: ...8 10 Nm 10 13 Spark plug tightening torque 16 18 Nm 10 Fixing screw reel 8 10 Nm 10 Coil fixing stud 8 10 Nm 11 Brake support screws 8 10 Nm 11 Brake support stud 8 10 Nm 12 Muffler fixing nuts 8 10 N...

Page 12: ...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 Carburettor Ignition...

Page 13: ...ending 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 i...

Page 14: ...k with new petrol check the seal of the tank the cap and the car burettor pipe b Cold starting test With the throttle control in CHOKE start the engine a few times to check it runs normally c Check th...

Page 15: ...petrol taken from the tank as the engine runs is compensated by a breather pipe in the cap See the relevant section 15 for advice on resolving problems due to the malfunctioning of the petrol supply...

Page 16: ...erform the above operations in reverse WARNING Before refilling the tank with new fuel check that the petrol pipe is intact 5 2 Cleaning the tank 1 Remove the tank 5 1 2 Remove the clamp 1 from the si...

Page 17: ...nk with new fuel check that the petrol pipe is intact 5 3 Checking and cleaning the breather pipe 1 Remove the cap 8 and pull out the gasket 9 and the sponge 10 2 Check that the gasket 9 is intact and...

Page 18: ...G SYSTEM 6 1 Removing the starter assembly 1 To get access to the starter assembly 1 the cover 2 must be removed by unscrewing the three nuts 3 2 Refit the starter assembly 1 by tightening the cover n...

Page 19: ...to complete another 2 3 turns before compressing the spring 9 Refit the starter assembly 6 1 6 3 Replacing the hooks 1 Remove the starter assembly 6 1 2 Undo the screw 7 clockwise and remove the cove...

Page 20: ...and can be inspected without having to remove other parts 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...

Page 21: ...ot 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 pe...

Page 22: ...ake butterfly rod 8 and slide the small rod 9 for the relative com pensation spring upwards 6 Disconnect the wire 10 from the choke but terfly lever remove the carburettor 11 and the gasket 12 7 Loose...

Page 23: ...Mount the carburettor following the previous points 8 7 and 6 in reverse order remembering that It is always advisable to replace the washer 18 and the gasket 15 of the float chamber the float 17 must...

Page 24: ...um speed must be between 1800 150 rpm 3 Turn the screw 24 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...

Page 25: ...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...

Page 26: ...rify that the move ment of the mobile levels 8 don t damage the con tact with level air support 9 position CHOKE NOTE The engine s maximum speed must be between 2900 100 rpm if you do not read this va...

Page 27: ...ck the nut 14 9 3 Replacing the lever support 1 Position the choke lever to minimum SLOW position 2 Remove the carburettor 8 1 3 Disconnect the accelerator cable 3 and remo ve the breather pipe 16 and...

Page 28: ...2 Connect the tester 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...

Page 29: ...which secure the coil 7 At the bottom of the machine to which the engine is fitted release the safety brake Rotate the flywheel 11 so as to bring the magnetic inserts next to the poles of the core of...

Page 30: ...ston 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 10 2...

Page 31: ...the faston 6 from the micro switch 2 Using an Ohmmeter tester 7 make con tact with the prods on terminals 1 COM of the microswitch 8 and engine earth connection The instrument should read microswitch...

Page 32: ...freely and remove any remains of grass and mud 4 Refit the starter assembly 6 1 5 Start the engine release the lawnmower lever and check that the engine stops within 3 secon ds 6 If it stops after 3 s...

Page 33: ...ket 13 6 When fitting perform the above operations in reverse tightening the screws 11 and the stud 12 to the torque indicated 7 Refit the starter assembly 6 1 and the filter assembly 7 1 8 Start the...

Page 34: ...12 1 Removing and replacing the muffler 1 Remove the two nuts 1 that fix the guard 2 and the muffler 2 Take out the muffler 3 and the heatproof baffle 4 3 On assembly thoroughly clean the cylinder co...

Page 35: ...ect 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 gauge on the engine side should position itself in the green zone...

Page 36: ...heck the gap between 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...

Page 37: ...the cylinder head 14 and cylinder sur faces 16 9 Carefully clean the inside of the combustion chamber and remove possible deposits from the valve seats 10 Turn the flywheel by hand to move the piston...

Page 38: ...and EX 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...

Page 39: ...eat and rim 10 Check the free length of the spring 23 and replace the spring of it is less than 28 5 mm 11 When mounting carefully clean the valve guides and housings of any foreign body apply a film...

Page 40: ...l 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 When fitting the flywheel check that the key 31 is in good con...

Page 41: ...f necessary replace the gasket 35 and refit the closure plate 33 tightening the screws to the torque indicated 5 Refit the magneto flywheel 13 5 13 7 Replacing the upper compression ring of the engine...

Page 42: ...he insertion with the help of a pipe 46 of a diameter of approximately 30 35 mm Tightening torques 2 Spark plug tightening torque 16 18 Nm 6 Valve cover fixing screws 8 12 Nm 13 Cylinder head screws 5...

Page 43: ...mpty the tank of fuel 5 1 2 Drain the oil in the sump by removing the filler plug and turning the mower on its side 3 Disconnect the throttle cable 1 and the engine brake cable 2 4 Remove the blade as...

Page 44: ...indications provided 6 On assembly follow the steps described in re verse and always replace the gasket 7 between cover and sump ensure that the two centring pins 8 are correctly inserted always repl...

Page 45: ...7 72 EX 4 Check the regular movement of the pressure reducer 11 and the efficiency of the spring 12 the whole group must always be replaced in the case of breakage or irregular operation of the pressu...

Page 46: ...s the whole group fixed by a plate 16 and a screw 17 must be replaced 8 When assembling the new group care must be taken over the correct positioning of one scraper washer 18 under the sliding pin 19...

Page 47: ...to assess the advisability of performing all the operations described or only part of them depending on the type of engine problems encountered 1 Remove the engine from the machine 14 1 2 Remove the...

Page 48: ...t be replaced The cylinder must be replaced if it shows striping due to a seizure 10 Use a section of an old ring 31 to carefully clean the inside of the piston 27 ring housings en suring that the oil...

Page 49: ...n the piston 27 and replace the piston if they are more than 13 05 mm even at a single point 15 Fit the cap 24 to the connecting rod 25 and check the diameter from the gudgeon pin side and the crank s...

Page 50: ...t the end check the displacement by rotating the shaft The shaft must be replaced if the displacement exceeds 0 10 mm IMPORTANT A bent shaft must never be re paired WARNING DANGER A bent shaft causes...

Page 51: ...shaft 35 and the connecting rod cap 24 with the relative screws 26 taking care with the position references 42 so as to avoid inverting the mounting direction of the cap Close the screws 26 to the in...

Page 52: ...ng torques 6 Union screws under carter and sump 8 12 Nm 17 Counterweight governor fixing screw 8 10 Nm 28 Fixing screws lower connecting rod cap 15 Nm Technical information Oil sump capacity 0 55 litr...

Page 53: ...r and the choke 8 1 The spark plug is badly connected or faulty Check spark 10 1 or replace spark plug Blocked air filter Execute the filter cleaning 7 1 Fouling in the combustion chamber Dismount the...

Page 54: ...e engine overreved Governor blocked due to breakage of centrifugal assembly or breakage of external governor springs It is pos sible that the governor is dirty Check the entire governor system 9 and 1...

Page 55: ...Release 00 02 2008 Engine WBE 0701 WBE 0704 pag 55 Service manual BACK back to the index...

Page 56: ...pag 56 Release 00 02 2008 Engine WBE 0701 WBE 0704 Service manual BACK back to the index...

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