Husqvarna K 770 OilGuard, Workshop Manual

Page 1: ...Workshop manual K770 Vac Dry Cut English 701 002 ...

Page 2: ...epair and servicing 5 1 Product overview Dry Cut 15 5 2 Product overview Vac 16 5 3 To disassemble into basic modules 17 6 Repair and servicing 6 1 Starter 24 6 2 Ignition system 27 6 3 Flywheel 31 6 4 Air filter 32 6 5 Fuel system 34 6 6 Carburetor 36 6 7 Decompression valve 44 6 8 Cylinder and piston 46 6 9 Piston wear 49 6 10 To assemble the piston 50 6 11 To assemble the cylinder 51 6 12 Crank...

Page 3: ...pair and do servicing All personnel that do repair or do servicing on the product must read and understand the manual 1 4 Revisions Changes to the product can cause changes to the maintenance work and spare parts Separate information is sent out for each change Read the manual together with all received information about changes to maintenance and spare parts for the product 1 5 Safety WARNING All...

Page 4: ...parks and cause ignition of flammable materials Replace all damaged or missing warning symbol decals Gasoline and its fumes are poisonous Gasoline can cause damage to the eyes and the skin Gasoline can cause breathing problems Gasoline is flammable 2 3 Symbols on the product WARNING Careless or incorrect use can result in injury or death to the operator or others Read the manual carefully and make...

Page 5: ...3 Servicing data 3 1 Symbols in the diagrams Tightening torque Nm 701 002 Servicing data 5 ...

Page 6: ...3 2 Tightening torques K770 Vac Dry Cut 3 5 4 6 4 6 4 6 2 0 7 9 3 5 4 6 6 Servicing data 701 002 ...

Page 7: ...3 3 Tightening torques K770 Vac Dry Cut 11 12 10 12 5 7 11 13 11 13 11 13 7 9 17 23 701 002 Servicing data 7 ...

Page 8: ...3 4 Tightening torques K770 Dry Cut 30 8 22 4 4 6 8 10 25 25 30 8 10 1 2 9 11 2 4 1 6 8 4 6 10 12 8 10 8 10 8 10 4 6 6 8 8 Servicing data 701 002 ...

Page 9: ...3 5 Tightening torques K770 Vac 25 25 8 10 4 6 1 2 8 10 8 10 18 22 4 4 4 6 6 8 701 002 Servicing data 9 ...

Page 10: ...3 6 Tightening torques K770 Dry Cut 13 5 5 6 10 12 6 6 4 3 5 7 5 6 8 25 30 9 11 10 12 10 Servicing data 701 002 ...

Page 11: ...3 7 Tightening torques K770 Vac 13 6 8 20 25 5 5 6 10 12 6 6 4 3 5 7 5 6 8 25 30 9 11 701 002 Servicing data 11 ...

Page 12: ...isassemble the primary bearing and assemble the crankshaft 544 10 36 02 4 Bearing press To assemble the primary bearing 506 37 61 02 5 Bearing puller Remove the primary bearing from the crankshaft 531 00 48 67 6 Combination wrench General 506 38 26 01 7 Compression tester To examine the compression in the cylinder 531 03 16 86 8 Bearing press To disassemble and assemble the clutch drum ball bearin...

Page 13: ... pin 505 38 17 05 13 Hose catcher To catch the fuel filter in the tank 502 50 83 01 14 Kit for piston service To do service on the piston 502 50 70 01 15 Piston stop To disassemble the clutch 504 91 06 05 16 Pressing device To disassemble and assemble the blade shaft bearings and axle 575 96 20 01 17 Pressure tester To examine the carburetor fuel lines and check valve 501 56 27 01 18 Pressure test...

Page 14: ...he idle speed 501 60 02 03 22 Tachometer To adjust the idle and maximum speed 502 71 14 01 23 Test spark plug To do service on the ignition unit 502 71 13 01 24 Universal puller To disassemble the support washer of the clutch on the crankshaft To divide the crankcase 504 90 90 02 25 Key Torx T27 General 502 71 27 02 26 Grease To lubricate the gearbox and the fan bearings 588 81 48 01 27 Internal b...

Page 15: ...tarter rope handle 7 Starter 8 Belt adjustment screw 9 Lock screws for belt adjustment 10 Rear belt guard 11 Fuel tank 12 Throttle trigger 13 Rear handle 14 Throttle trigger lock 15 Air purge bulb 16 Decompression valve 17 Fan 18 Connection bend 19 Bracket 20 Choke lever 21 Viewing glass for fuel 22 Oil guard button 23 Stop switch 24 Blade guard extender 25 Dust Shield 701 002 Product overview for...

Page 16: ...r rope handle 7 Starter 8 Belt adjustment screw 9 Lock screws for belt adjustment 10 Rear belt guard 11 Fuel tank 12 Throttle trigger 13 Rear handle 14 Throttle trigger lock 15 Air purge bulb 16 Decompression valve 17 Bracket 18 Choke lever 19 Viewing glass for fuel 20 Stop switch 21 Blade guard extender 22 Dust Shield 16 Product overview for repair and servicing 701 002 ...

Page 17: ...5 3 To disassemble into basic modules This chapter shows how you can disassemble and assemble the product in its basic modules Dry Cut Vac 701 002 Product overview for repair and servicing 17 ...

Page 18: ...Dry Cut 1 Remove the connection bend 2 Loosen the belt tensioner with the combination wrench 3 Loosen the nuts and remove the front belt cover 4 Remove the belt from the pulley and remove the cutting head 5 Remove the 3 screws on the rear belt guard Remove the guard 18 Product overview for repair and servicing 701 002 ...

Page 19: ...ove the belt cover 3 Remove the belt from the pulley and remove the cutting head 4 Remove the 2 screws on the rear belt guard Remove the guard Note Tightening torque when you assemble 9 11 Nm 5 3 4 To remove the fan Dry Cut 1 Remove the cover 2 Before you remove the fan make a note of how the fan belt is put This is to make it easier to assemble the fan 701 002 Product overview for repair and serv...

Page 20: ...r filter is removed Dust particles must not fall down in the carburetor inlet Removal of waste is best done with a vacuum cleaner 1 Remove the 3 screws and remove the cover 2 Remove the 2 screws and remove the air filter holder and the air filter 20 Product overview for repair and servicing 701 002 ...

Page 21: ... 2 Push the collar of the rubber seal through the hole 3 Remove the cylinder cover 5 3 7 To remove the carburetor 1 Remove the screw 2 Lift the carburetor until you can access the gasoline hose and the hose to the air purge bulb 701 002 Product overview for repair and servicing 21 ...

Page 22: ...duct Remove the starter air filter cover and cylinder cover before you remove the air duct 1 Lift the cable for the stop switch out of its holders 2 Remove the ignition cable at the spark plug and lift the cable out of its holder in the cover 3 Remove the 3 screws on the air duct cover Remove the air duct cover 22 Product overview for repair and servicing 701 002 ...

Page 23: ...rbers Before you remove the vibration absorbers you must remove the following parts Air filter Cylinder cover Top air duct cover The screw holding the carburetor Starter Air duct cover Cable lug by the ignition module Cable at the ground point 5 3 11 To remove the vibration damping units 1 Remove the screws of the vibration damping units 701 002 Product overview for repair and servicing 23 ...

Page 24: ...y Then pull it out through the notch for the starter rope Pull out most of the starter rope but keep some to make a knot 2 Put the other end through the cover and on through the handle Make two knots as in the illustration 6 1 3 To load the return spring 1 Put the starter rope in the notch 2 Wind the starter rope handle 4 turns around the hub 3 Pull out the starter rope handle to make the rope com...

Page 25: ...er pulley The spring in the starter pulley decreases vibrations The spacer sleeve around the center screw is the top bearing point for the starter pulley Note Make sure that the spacer sleeve does not fall off 1 Align the starter pulley notch with the end of the spring when assembling Put the center bolt into the starter pulley assembly 6 1 7 To remove the spring assembly WARNING Always use protec...

Page 26: ...prings work and the starter pawls move freely Disassemble and clean if necessary 6 1 11 To disassemble the starter pawls Note The position of the washer is below the starter pawls against the flywheel Make a note of the position of the springs in relation to the flanges on the flywheel 1 Remove the shoulder screws 6 1 12 To assemble the starter pawls Note The spring must not get caught between the...

Page 27: ... sequence is in the diagram in the illustration The dotted line shows the voltage if the current is not broken Current moves through the coil by the permanent magnet on the flywheel The electronic digital unit senses the voltage in the primary coil It breaks the current before the piston is at the high turning point Until this point the primary coil is in a closed circuit With an open circuit the ...

Page 28: ...re brush Note An electrode with soft edges and damaged ceramic around it can cause pre ignition You must replace a spark plug with soft edges 02 in 0 5 mm 1 Replace the spark plug with the test spark plug See Servicing tools overview on page 14 2 Move the stop button to the run position Ground the test spark plug Pull the starter rope handle as if you start the product 3 Ground the test spark plug...

Page 29: ...e made with a multimeter If there is no spark after this test examine the short circuit cable 6 2 7 To examine the short circuit cable and the stop switch 1 Remove the starter and the short circuit cable on the ignition unit 2 Put back the starter and check if the spark plug makes a spark 3 Examine the short circuit cable a Use an instrument or a battery in series with a test lamp b Connect to the...

Page 30: ...on the left side with a screwdriver and pull the right side half way out 4 Remove the switch 6 2 9 To assemble the stop switch 1 Push the switch halfway into position 2 Push in the left side until it locks 3 Push in the right side 1 2 3 4 Put the cables back on the stop switch 5 Tighten the screw 4 4 5 30 Repair and servicing 701 002 ...

Page 31: ...of 10 12 Nm 6 3 Flywheel 6 3 1 To remove the flywheel Use a Husqvarna flywheel puller Refer to Servicing tools overview on page 13 1 Remove the starter and lower air duct 2 Loosen the springs and put the start hooks in their outer positions 3 Put a 13 mm socket on the center screw of the flywheel 4 Attach the flywheel puller on the socket with the screw that is supplied with the flywheel puller 5 ...

Page 32: ...torque wrench to tighten the nut 1 Align the key in the flywheel with the keyway on the crankshaft Install the washer and nut 2 Remove the tool and put the springs on the start hooks 6 4 Air filter 6 4 1 Function The centrifugal cleaning is the first step in the air cleaning of the inlet air The blades on the flywheel supply the cylinder with cool air This is shown with large arrows in the illustr...

Page 33: ...ove the air filter on page 20 2 When you replace the air filter examine and clean the inlet tube 3 Remove dust from dry cutting with compressed air Remove material from wet cutting mechanically 4 Make sure that the rubber seal on the air duct cover is not damaged and that it is correctly attached in the cylinder cover 5 Replace the service filter if it is damaged 6 Do not clean the paper filter Re...

Page 34: ...e Dirty filters must not be cleaned but replaced with a new one 6 5 3 To examine the fuel system for leakages To examine the fuel hose use a pressure monitor Refer to Servicing tools overview on page 13 Connect the adapter to the pressure monitor with a short hose 1 Pump up the pressure to approximately 7 psi 0 5 bar Move to the next test if the pressure drops 2 To make sure the fuel hose does not...

Page 35: ...ected to the carburetor The pump causes a vacuum in the fuel chamber and fuel is pulled into it When the fuel chamber has been fully filled unwanted fuel is pushed to the tank through return hose 2 This means that the fuel level in the carburetor does not get too high 6 5 9 To examine the air purge To examine the air purge use Husqvarna test instrument for fuel lines and check valves See Servicing...

Page 36: ...and push the pump out 6 6 Carburetor 6 6 1 To remove the carburetor from the inlet system 1 Remove the service filter 2 Clean the outer parts of the carburetor before you remove it from the inlet system 3 Remove the carburetor from the bracket 4 Pull off the hose from the carburetor and divide the units 36 Repair and servicing 701 002 ...

Page 37: ...life of the engine Dust on the inner side of the seals means there is defective or incorrectly installed components 1 Look for leaks Make sure the rubber guides are not cracked 6 6 4 To assemble the inlet manifolds The parts must be installed correctly Make a note that the guide to the inlet is irregular Make a note of the groove on the holder 701 002 Repair and servicing 37 ...

Page 38: ... manifolds one at a time into their correct position 3 Install the support insert 6 6 5 Carburettor components 4 6 7 8 9 2 1 10 3 5 12 11 14 13 1 Throttle valve 2 Air valve 3 Choke valve 4 Pulse line to the pump diaphragm of the carburetor 38 Repair and servicing 701 002 ...

Page 39: ...od 2 Remove the 2 screws 6 6 8 Needle valve 6 6 8 1 Indications of a needle valve leak There are many symptoms of a needle valve with a leak A product that is used for short periods is usually not easy to start when it is warm Fuel leaks into the venturi and gives too much fuel for the next warm start With a cold start the fuel chamber above the needle valve is dry This is the situation especially...

Page 40: ...si 100 0 5 bar and then decrease much slower or stop A pressure drop after 7 psi 0 5 bar means there is a leak at the needle valve If the needle valve does not open at 36 psi 2 50 bar max permitted pressure test blow through the hole for filter compensation 1 to open it If the pressure does not increase the cause can be a damaged pump diaphragm 1 6 6 8 4 To examine and clean the needle valve Do a ...

Page 41: ...oken 6 6 10 To examine the chamber diaphragm You cannot examine the chamber diaphragm with a pressure check To examine the diaphragm see To examine the measurement chamber diaphragm on page 42 A hole in the diaphragm stops the fuel supply 6 6 11 To examine the check valve for the air purge bulb This valve in the carburetor stops fuel leaks out of the carburetor if leaks occur in the air purge bulb...

Page 42: ...r the inlet after the air filters and gives the air chamber the same pressure 6 6 13 To examine the measurement chamber diaphragm Assemble the parts in the order shown in the figure The gaskets 1 are the same 1 1 1 Examine the diaphragm visually Fuel on the top side to the cover is a sign of leaks If there is fuel on the top side replace the diaphragm 6 6 14 Function pump unit The pump diaphragm 1...

Page 43: ... carburetor channels When you do servicing on the carburetor also blow out particles from the channels with compressed air 1 Disassemble the chamber diaphragm the pump diaphragm and the needle valve 2 Open the choke valve to give free air flow through the venturi 3 Clean the channels with compressed air The rings show where to blow clean 6 6 17 To examine the valve axles Leakage from the valve axl...

Page 44: ...e exhaust fumes are poisonous Adjust the idle speed outdoors 1 Run the machine warm for approximately 5 minutes 2 Keep the instrument with the arrow pointing down to the position of the spark plug 3 Adjust the idle screw to an idle speed of approximately 2 700 rpm If the cutting blade rotates at this speed the clutch or the friction retarder must be examined 6 6 20 To assemble the air valve 1 Atta...

Page 45: ... decompression valve moves 2 Clean the decompression valve 3 Apply leakage spray or soap water on the decompression valve before installation 4 Install the decompression valve See To install the decompression valve on page 45 5 Move the stop button to the stop position 6 Slowly pull the starter rope handle and look at the decompression valve to make sure that there are no leaks 6 7 4 To install th...

Page 46: ...f the tests The mean value for a new engine is approximately 10 bar 150 psi Values less than 8 bar 120 psi show faults with or on the cylinder piston or piston rings 6 8 2 To remove the cylinder Divide the machine at the vibration dampening element for easier access to the cylinder You can tighten the engine body in a vice Use soft guards 1 Remove the cylinder 2 Remove the cylinder gasket 6 8 3 To...

Page 47: ...n 4 Push out the wrist pin by hand If it is tight use a small hammer and light force 5 Press the needle bearing out of the connecting rod 6 Remove the piston rings 6 8 4 Examine the cause of failure Examine the cause of low compression or failure With usual wear and many hours of operation components must be examined and replaced if necessary A product that has not been used for many hours must be...

Page 48: ...has been worn smooth A product with a worn piston is difficult to start because of the decreased valve function of the piston 6 8 7 Piston wear tolerances 6 8 7 1 Piston ring play If the piston ring play is more than 006 in 0 15 mm the piston ring groove must be measured as set out below 1 6 8 7 2 Piston ring groove If the piston ring groove is larger than 06 in 1 6 mm the piston must be replaced ...

Page 49: ...oo hot The scores are usually on the exhaust side which is the hottest The inlet side can show equivalent damage Examine the product to see if it has broken down because of an incorrect oil mixture or no oil at all If there is oil on a piston that is too hot it can carbonize If not check if the connecting rod or the crankcase has a thin layer of oil If there is sufficient oil inlet leakage can be ...

Page 50: ...ssemble them 1 Turn the arrow in the direction of the muffler when you assemble the piston on the connecting rod 2 Install the needle bearing in the connecting rod 3 Install a circlip in the piston 4 Hold the piston in position push in the wrist pin and install the other circlip 50 Repair and servicing 701 002 ...

Page 51: ...ssor move along the piston Tighten the screws crosswise to a torque of 10 11 lbf ft 14 15 Nm 6 12 Crankcase 6 12 1 To examine the crankcase for leaks A crankcase with a leak has lower crankcase compression A typical sign is that the product cannot easily start The tool kit cylinder seal refer to Servicing tools overview on page 12 has parts for sealing the exhaust and inlet ports of the cylinder I...

Page 52: ...econds the pressure can drop at the most to 3 psi 0 2 bar 5 If there is a leakage apply a solution of soap and water or use a leakage spray to find it a Examine the seals on the crankshaft b Examine around the gaskets where the crankcase halves are joined and at the base of the cylinder c Look for cracks on the crankcase 6 12 2 To remove the crankcase seal To replace the crankcase seal rings use a...

Page 53: ...kcase seals 1 Apply leakage spray or a solution of soap and water to examine the seals for leaks 2 Use the pressure tester to find leaks 6 12 5 To disassemble the crankcase Divide the crankcase with a universal puller and a grip plate from Husqvarna Refer to Servicing tools overview on page 14 and Servicing tools overview on page 13 1 Disassemble the basic modules from the crankcase 2 Remove the 6...

Page 54: ...overview on page 12 To change the bearing you must use two Husqvarna bearing press kits See Servicing tools overview on page 12 1 Put the puller plate behind the bearing Make sure that the plastic components on the balance weights are not damaged The puller must be in a position where the ears 1 are free The two parts of the puller head must not come nearer together than to the center ring 2 If th...

Page 55: ...hold it below the crankcase half 2 Put the screw through the washer and put the screw in the support plate 3 Lock the screw and turn the nut until the bearing is in the stop in the crankcase half 6 12 8 To assemble the crankcase Use the bearing press refer to Servicing tools overview on page 12 to press the crankshaft into the bearing The mandrel threads for the clutch side is M10V and for the fly...

Page 56: ...half Make sure that the connecting rod is not held against the crankcase half 5 Put the guides in the holes 6 Install the new crankcase gasket 7 Assemble the other crankcase half using the same procedure 1 2 a Change to the other mandrel b Make sure the position of the connecting rod is correct c Align the guides to prevent damage to the crankcase gasket d Put in the screws before the crankcase ha...

Page 57: ...filter cover and the filter bracket 1 Lock the crankshaft with the piston stop 2 Release the clutch clockwise It has a mark with the direction OFF CAUTION Do not hit the puller This will break the piston Do not use a hammer or equivalent without the piston stop It can cause damage to the lock mechanism of the flywheel keyway key 3 Pull the clutch drum from the axle Make a note of the positions of ...

Page 58: ...rench 1 Tighten the clutch with a torque of 37 43 Nm 6 13 4 To remove the clutch springs 1 Put a large screwdriver in each spring end 2 Expand the spring using circlip pliers and remove the spring 6 13 5 To install the clutch springs 1 Put a large screwdriver in each spring end 2 Expand the spring using circlip pliers and install the spring 6 13 6 To examine the clutch shoes and hub CAUTION Do not...

Page 59: ... the cover 3 The cover has different contours One side aligns with the sleeve when disassembling and the other aligns with the clutch drum when installing The kit also contains the screw 4 with washers and nut Lubricate the threads of the screw and the washers 1 2 3 4 1 Put the screw with the large washer on the bearing 2 Put the hex key in a vice Put the head of the screw on the hex key Put the s...

Page 60: ...mble the blade guard 1 Remove the cutting blade from the blade guard 2 Put the cutting head in a vise with the pulley down 3 Lock the belt pulley with a mandrel or a screwdriver Note The illustration shows the screwdriver and the wrench from below 4 Remove the pulley 5 Remove the cover 60 Repair and servicing 701 002 ...

Page 61: ...6 Remove the blade guard extender and dust shield 7 Remove the spring from the metal side of the blade guard extender 8 Remove the screw that hold the dust shiel 701 002 Repair and servicing 61 ...

Page 62: ...1 Loosen the 4 screws 2 Remove the gearbox lid and the gasket You can use a mandrel in the 2 holes in the blade guard 3 Remove the gears Note Do not remove the gears from their shafts They are supplied as a kit 62 Repair and servicing 701 002 ...

Page 63: ...ngs use a press and Husqvarna bearing press Refer to Servicing tools overview on page 12 Make sure that the blade guard is level 1 Put a wooden block of applicable size below bearing 1 and 2 as support 2 Use the small support from the tool kit to push the bearings into position 6 15 4 To install bearing 3 To install the bearing you can use a standard press in combination with a Husqvarna bearing p...

Page 64: ...aring For support on the other side use a piece of a rod with diameter 40 44mm 2 You can also use a support for the outer edge of the gearbox 6 15 5 To install the gears 1 Install the gears 2 Install a new gasket and attach the cover with the 4 screws 64 Repair and servicing 701 002 ...

Page 65: ... with a grease gun 6 16 Fan Dry Cut 6 16 1 To disassemble the fan 1 Remove the fan from the product See To remove the fan Dry Cut on page 19 2 Put the combination wrench or a 13mm socket in a vise and loosen the nut 3 Remove the nut fan pulley and shaft 701 002 Repair and servicing 65 ...

Page 66: ...g press Use a Husqvarna bearing press See Servicing tools overview on page 12 1 Put an extension and a 13mm socket in a vise There must be a minimum of 40mm from the top of the socket to the jaws of the vise 2 Apply some drops of oil to the threads on the screw 3 Assemble the tool Make sure that the sleeve in the bearing set is turned as in the picture Pull out the first bearing and the seal 4 Rem...

Page 67: ...t of applicable size below the edge of the fan housing 2 Use a mandrel of maximum diameter of 20mm 6 16 3 To install the fan bearings To install the bearings you can use a Husqvarna bearing press for the fan bearings Refer to Servicing tools 701 002 Repair and servicing 67 ...

Page 68: ... a 13mm socket in a vise 2 Apply some drops of oil to the threads on the screw 3 Put one bearing on top of the bearing housing 4 Assemble the tool kit Make sure that the sleeve in the bearing set is turned as in the picture 5 Turn the fan Put the head of the screw into the 13mm socket 68 Repair and servicing 701 002 ...

Page 69: ...he housing 7 Do steps 3 to 6 with the second bearing 8 Before you install the seal apply grease on top of the bearing Refer to Servicing tools overview on page 14 9 Make sure that the seal is level before you tighten the nut 701 002 Repair and servicing 69 ...

Page 70: ... Before you put the seal apply grease on top of the bearing See Servicing tools overview on page 14 5 Make sure that the seal is level before you press it into position 6 17 Dust bag Dry Cut 6 17 1 Different dust bags There are 2 types of dust bags for Dry Cut Dust bags that you use one time and discard when they are full Dust bags that you remove the dust from and use again 70 Repair and servicin...

Page 71: ...ess it is in a garbage bag Dust can spill out in the air 1 Put the dust bag in a garbage bag 2 Open the zipper of the dust bag 3 Put the dust bag fully into the garbage bag 4 Hold and shake the dust bag until it is empty 6 17 4 To assemble the dust bag 1 Put the check valve into the dust bag a Make sure that the screws on the lid point up b Align the check valve with the seam of the dust bag inlet...

Page 72: ...s possible to the handle Put a cloth on the throttle lock before you apply the pliers to prevent damage to the surface 1 Remove the carburetor See To remove the carburetor on page 21 2 Push in the lower part of the throttle lock with a v jaw tongue and groove pliers 3 Lift the lower part of the throttle lock and pull it out from the pin 4 Push out the spindle to the right side Use a rod with a dia...

Page 73: ...is 3800 rpm A winding in the ignition module 1 gives electric current to the OilGuard The analysis unit has a light emitting diode 2 The light hits a light sensitive phototransistor 3 The fuel flows between the diode and the phototransistor The OilGuard oil contains a yellow dye which absorbs the light from the light emitting diode In this mode the product is operating as usual If the product is f...

Page 74: ...he power supply for the OilGuard 1 Remove the filter and cylinder cover 2 Connect a multimeter to a ground point and the point of measure Measure at idle rpm The voltage must be 20 40 V AC 74 Repair and servicing 701 002 ...

Page 75: ...The switch is OFF Set the switch to the left position The switch is defective Replace The primary wire is grounded Repair or replace There are sparks at the spark plug Symptom Category Cause Solution Compression is good and fuel flows There is too much fuel Remove the fuel The carburetor is adjusted to give too rich mixture Repair adjust or replace the carburetor There is too much fuel mixture Adj...

Page 76: ...ed sud denly increases and then the engine stops There is no fuel Fill with fuel There is a blockage in the carburetor Clean 7 3 Engine stops during operation Remove the spark plug from the cylinder Hold the cylinder and pull the starter to see if there are sparks between the spark plug electrodes Symptom Category Cause Solution Engine suddenly stops The engine runs lean Adjust repair or replace t...

Page 77: ... decreasing temperature Clean Blockage because of dirt on the cylinder fin Clean Low quality fuel is being used Replace with good quality fuel The level of carbon has increased in the com bustion chamber Clean The spark plug tip is red hot Champion RCJ 6Y NGK BPMR 7A Adjust to 0 5 mm Other The air filter is too dirty Replace the air filter Too high load Lower the load 7 5 Other engine problems The...

Page 78: ...orn out Repair or replace the fan The check valve is not installed cor rectly Install the check valve correctly The hose is loose Attach the hose The bag is full Empty the bag Vac There is too much dust Symptom Cause Solution Too much dust goes out in the air during operation The hose is loose Attach the hose 78 Troubleshooting 701 002 ...

Page 79: ...diagram Dry Cut 8 1 Wiring diagram OilGuard 3 2 2 3 1 1 1 1 2 3 3 2 1 OilGuard OilGuard plug ignition module 2 OilGuard stop switch ignition module 3 OilGuard stop switch ground 701 002 Wiring diagram Dry Cut 79 ...

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