小引擎的组装课件.ppt

1、Small Engine ReassemblyBriggs&Stratton OHVA Visual GuideObjectives:nReassemble an engine following concise steps and detailed notes taken by the student.nUtilize proper tool techniques.nReinforce lecture-based theoretical discussions.nUtilize and reference engine standards with appropriate engine ma

2、nuals.Procedure Notes:nFollow the reassembly steps precisely.Be sure to reference notes and sketches you created during engine disassembly.nYour engine may not be exactly like the engine in this presentation.Even if your Briggs&Stratton OHV engine is not exactly like the model used in this presentat

3、ion,many of the procedures will be the same.nUse reassembly grease on all internal parts and follow all specifications!Pre-Assembly CleaningClean all internal parts in the parts cleaning cabinets.Remove excess solvent with compressed air.Eye protection and chemical resistant gloves are required.Step

4、 1:Install the CrankshaftReminder:Tapered end to the front of the engine.Pre-operation greaseStep 2:Reassemble the Piston Rings and Connecting RodReminder:The rings must be replaced correctly.Review your sketch of connecting rod and piston ring orientation.Step 2:Reassemble the Piston Rings and Conn

5、ecting RodConnecting rod&piston orientation.Arrow on piston and MAG abbreviation to the magneto side of the engine.wrist pin clipsStep 3:Install the Piston and Connecting Rod in the CylinderReminder:Clean and coat cylinder wall with lubricant.Use piston ring compressor.Install in the correct orienta

6、tion.Step 3:Install the Piston and Connecting Rod in the CylinderUse your thumbs or the handle of a mallet to gently insert the piston assembly.Rotate the crankshaft to prevent it from striking the connecting rod during reassembly.Step 4:Replace Connecting Rod CapReminder:Lubricate interior of rod c

7、ap and connecting rod.Replace cap and rod in the correct direction.Replace oil splash and rod cap lock.Torque screws properly.Arrow toward cylinderShort screw and oil splash away from cylinderStep 5:Replace TappetsNote:Lubricate each tappetStep 6:Replace Cam Gear Reminder:Make sure journal is secure

8、.Line up timing marks.Lubricate all bearing surfaces.Step 7:Install Crankcase Cover Reminder:Use correct gasket.Tighten bolts in correct sequence by skipping across the cover.Replace oil seal if needed.Adjust end play if needed.Step 8:Install FlywheelInstall flywheel and key.Install Starter Cup and

9、NutTorque flywheel nut using a strap wrench and ft.lb.torque wrench.Installing Cylinder Head&Adjusting Overhead ValvesReturn to your measurement sheets in Chapter 9 to record your measurements.Step 9:Insert Valves Into HeadInsert valves from the bottom of the head,while using your thumbs to lock the

10、 valve retainer.Oil seal on intake valveExhaust valve guide risesStep 10:Install the Cylinder HeadReminder:Install head gasket first.Torque head bolts in a crisscross pattern.Step 11:Install Pushrods&Valve Wear PlatesPushrodValve Wear PlatesStep 12:Align Rocker Arms with Push Rods&Valve Wear PlatesR

11、eminder:Use the rocker arm as a fulcrum to slightly compress each valve spring in order to slide its opposite end on top of the push rod.Step 13:Prepare the Cylinder for Valve AdjustmentReminder:Rotate piston to TDC compression.Use a screwdriver in the sparkplug opening as a guide or align the PTO k

12、eyway to the cylinder.Now rotate the flywheel clockwise until the magnet points straight up.This disengages the compression release on the camshaft.Step 14:Check Valve ClearanceReminder:According to specification,insert a flat feeler gauge between the rocker arm and valve wear plate.Make adjustments

13、 if out of gap tolerance.Step 15:Adjusting Valve Clearance1.Insert feeler gauge2.Loosen locking screw,while holding adjustment nut.3.Adjust clearance with the adjustment nut.4.Hold adjustment nut and lock rocker arm.Note:Dont forget gasket.Short bolt to the top.Step 16:Replace Valve CoverStep 17:Ins

14、tall ArmatureNote:Thread kill wire through port in block.Bolt armature to block.Adjust armature air gap with shim or business card.Step 18:Insert Heat Shield Note:One screw onlyReminder:Refer to your drawings to ensure all linkage is correctly assembled.CarburetorLinkageGovernorArm4 BoltsStep 19:Rep

15、lace Linkage Plate Insert Kill WireStep 20:Replace Carburetor1.Attach spring&linkage to carburetor2.Insert both gaskets&spacer.Step 21:Reset Governor Reminder:Ensure that all linkage travels freely.Confirm that throttle butterfly is open completelySet throttle to fullStep 21:Reset Governor Procedure

16、:Use a 1/4”nut driver and 3/8”.Rotate governor shaft counter clockwise until it stops(do not force).Tighten governor arm lock with 3/8”wrench.Step 22:Insert Spark PlugStep 23:Replace Blower HousingNote:Linkage plate flange mounts with the blower housing top.Weave the blower housing over,under,and ov

17、er.Step 24:Replace MufflerNote:Include gasket.#30 star tool required.Replace muffler guard.One bolt at rear of muffler and four screws at front.Step 25:Replace Fuel TankNote:Replace fuel line.Four bolts front and back.Step 26:Replace Throttle&Fuel Valve Cover PlateNote:Fuel valve must be in off posi

18、tion.Throttle must be at half.Step 27:Replace Air CleanerMounting Plate&GasketFilter&CoverSteps 28-29:nFill Crankcase with clean oil.nFill fuel tank 1/3 full with gasoline.Be sure to add gasoline,not any other fuels.Step 30:Start and Run EngineTurn run switch“ON”and set throttle to 1/2.No starting f

19、luid should be needed.Reminder:Only while instructor is present.Use engine stand and vice.Step 31:Adjust Carburetor&Take MeasurementsTemperature ReadingsFull Throttle RPM&Carburetor AdjustmentStep 32:Remove Fuel&LubricantPlace fuel and lubricant into their appropriate containers.Reassembly Wrap-UpnPlace a piece of tape on your engine that has your name as well as a report of how the engine ran.Return engine to storage area.nInventory and clean all tools in your assigned box.nClean and return your engine storage bin to its storage area.nClean and straighten your area.