Tecumseh VLV Technician's Handbook
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Tecumseh VLV Technician's Handbook

Tecumseh VLV Technician's Handbook

4-cycle
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This handbook covers VLV40 - 675.
Other illustrated Tecumseh 2 and 4-Cycle Engine and
Transmission handbooks, booklets and wall charts are
available from Tecumseh.
For complete listing write, call or check our website at
www.TecumsehPower.com
ENGINES
Tecumseh Products Company
Engine & Transmission Group
900 North Street
Grafton, WI 53024
Phone: 262-377-2700
FAX: 262-377-4485
www.TecumsehPower.com
Form No. 695578 Rev. 6/02
TRANSMISSIONS
&
Tecumseh Europa S.p.A.
Strada delle Cacce, 99
10135 Torino, Italy
Tel. 011 39 11 391-8411
Telefax 011 39 11 3910031
Litho in U.S.A.
TECUMSEH
T E C H N I C I A N ' S
VLV
(Vector)
4-CYCLE
ENGINES
ENGINES
TRANSMISSIONS
&
H A N D B O O K

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Summary of Contents for Tecumseh VLV

  • Page 1 T E C H N I C I A N ' S H A N D B O O K This handbook covers VLV40 - 675. Other illustrated Tecumseh 2 and 4-Cycle Engine and Transmission handbooks, booklets and wall charts are available from Tecumseh.
  • Page 2 U.S. EPA emission regulations for SORE (Small Off Road Equipment), are certified to operate on regular unleaded gasoline, and include the following emission control systems: (EM) Engine Modification and (TWC) Three- way Catalyst (if so equipped). Tecumseh Website Visit the Tecumseh website at: www.TecumsehPower.com...

  • Page 3: Table Of Contents

    Table Of Contents Page Chapter 1 General Information ..................1-1 Engine Identification ....................... 1-1 Prior to 1999 ........................1-1 Short Blocks ........................1-1 Parts Identification ......................1-2 Parts List......................... 1-3 Oil and Fuel Specifications ..................... 1-4 Oil ..........................1-4 Fuel..........................1-4 Filling Fuel Tank ......................
  • Page 4 Table Of Contents (Continued) Page Chapter 4 Starters ......................4-1 Disassembly and Inspection ................... 4-1 Assembly and Inspection....................4-1 Stylized Rewind Starter with Plastic Retainer ..............4-2 Disassembly and Inspection ..................4-2 Assembly and Inspection .................... 4-2 12 Volt Electric Starters ....................4-3 Removal ........................
  • Page 5 Chapter 14 Engine Specifications .................. 14-1 Torque Specifications ....................14-2 Chapter 15 Education Materials and Tools ..............15-1 Tool Kit ......................... 15-2 Chapter 16 Sears Craftsman Reference Chart .............. 16-1 Decimal/Fraction Conversions ..................16-2 Page iii © Tecumseh Products Company 2002...
  • Page 6 • Allow engine to cool before refueling. this engine. Failure to do so can result in • NEVER fill fuel tank indoors. Fill fuel tank serious injury or death. Call Tecumseh outdoors in a well-ventilated area. Products Company at 1-800-558-5402 if •...
  • Page 8 • Allow engine to cool before refueling. this engine. Failure to do so can result in • NEVER fill fuel tank indoors. Fill fuel tank serious injury or death. Call Tecumseh outdoors in a well-ventilated area. Products Company at 1-800-558-5402 if •...

  • Page 9: Chapter 1 General Information

    Chapter 1 General Information Engine Identification Tecumseh engine model, specification and serial numbers are stamped or on a decal on the blower housing. The decal also contains any emission compli- ance information. The letters which precede the model numbers indicate...

  • Page 10: Parts Identification

    Optional Pre-Filter Parts Identification This is a parts breakdown of a typical VLV engine. Use this parts breakdown to identify parts. When ordering parts always refer to the engine model and specification SBV-XXX number stamped on the engine blower housing.
  • Page 11 Ref. Ref. Part Name Part Name Cap, Valve spring Cylinder Ass'y. Gasket, Valve cover Pin, Dowel Cover, Valve spring box Element, Breather Screw, 10-24 x 1/2 Cover, Breather Stud, Carburetor mounting Gasket, Breather cover Link, Governor Screw, Thread forming, 10-24 x 1/2 Spacer, Carburetor mounting gasket Body, Breather valve Lever Ass'y., Brake...

  • Page 12: Oil And Fuel Specifications

    C) will increase oil con- sumption. SAE10W40 is not recommended. SAE5W30 The oil sump capacity is 21 ounces or 1-1/4 U.S. Pints SAE10W (.62 liters). Tecumseh special-formulated oils are avail- able at your Authorized Tecumseh Servicing Dealer. Below 0 F (-18 SAE 0W30...

  • Page 13: Maintenance And Adjustments

    Maintenance and Adjustments Removing Debris from Engine Before each use, remove grass clippings, dirt and debris To prevent accidental starting WARNING from the following areas: when working on equipment, always disconnect spark plug wire and keep it way from spark plug by attaching it •...

  • Page 14: Spark Plug

    Install spark plug and tighten securely. NOTE Air Cleaner Assembly A resistor spark plug must be used for replacement (Tecumseh part no. 33636, or Champion part no. RJ-17LM). Carburetor If you think your carburetor needs adjusting, see your Electrodes Porcelain nearest Authorized Tecumseh Servicing Dealer.

  • Page 15: Seasonal Storage

    This prod- Grasp starter cord handle and pull out slowly using uct is available from your Authorized Tecumseh Servic- a full arm stroke. Repeat once. (This will distribute ing Dealer. oil throughout the cylinder to prevent corrosion Add fuel preservative/stabilizer according to during storage.)

  • Page 16: 4-Cycle Engine Theory

    4-Cycle Engine Theory Power Tecumseh four-cycle engines require four strokes or cycles to complete one power cycle. Both valves remain closed. As the piston reaches the Intake Before Top Dead Center (BTDC) ignition point, the spark plug fires, igniting the fuel-air mixture. In the time it Intake valve is open, exhaust valve is closed.

  • Page 17: Chapter 2 Air Cleaners

    Chapter 2 Air Cleaners General Information Polyurethane Pre-Filters These serviceable air filters utilize a polyurethane It is recommended that you take WARNING element which will clog up with use. The element special notice of all items discussed in the handbook and wear the should be cleaned and serviced in the following manner.

  • Page 18: To Service Air Cleaner

    To Service Air Cleaner Loosen cover screw (A). Swing cover down and remove from hinge (B). Pre-Filter Pull foam pre-filter out of air cleaner body (if equipped with pre-filter). Pull air filter out of air cleaner body. Clean air cleaner cover and body. Install a new paper filter (part no.

  • Page 19: Carburetion

    Inspection of the carburetor for dirt wear and fuel deposits should always be done before servicing the carburetor. Carburetor Identification Tecumseh carburetors are identified by a manufacturing TORX E-5 Stud number and date code stamped on the carburetor as shown.

  • Page 20: Float Bowl Service

    The carburetor is a float feed, nonadjustable type, with a one piece extruded aluminum body. The float bowl, float, nozzle, and venturi are nonmetallic, minimizing the corrosion and varnishing problems. "O" Ring Gasoline (fuel) vapors are highly Bleed WARNING flammable and can explode. Fuel Holes vapors can spread and be ignited by a spark or flame many feet away from engine.
  • Page 21 Remove the drain screw to access the spring, jet and "O" ring. Idle Passage The main jet should be inspected and cleaned if depos- its exist. Main Nozzle NOTES The float is held in the float bowl by the float pin which is pressed into tabs on top of the float support towers.

  • Page 22: Rebuilding Carburetor Body

    18. Drop the main nozzle spring into the main nozzle Disguard gasket. well in the float bowl. Put a small amount of oil on Disconnect and plug the fuel line. the main nozzle “O” ring and push the nozzle into Remove the carburetor mounting studs.
  • Page 23 NOTE Install a new welch plug over the idle fuel chamber with the raised portion up. Use a punch equal to To rebuild the Float Bowl, refer to the previous section on the size of the plug, to flatten the plug. Float Bowl Service.
  • Page 24 13. Press the new bulb and the new retainer into position using a deep reach socket as shown. 14. Install the air cleaner body over the carburetor. NOTE The VLV models use a closed loop breather system. The crankcase breather tube must be reconnected to the air filter body. 695578...

  • Page 25: Chapter 3 Governors And Linkage

    Chapter 3 Governors and Linkage General Information All Tecumseh 4-cycle engines of recent manufacture are equipped with mechanical type governors. As the Type I VLV Type II speed of an engine increases, centrifugal force moves Spool the weights outward, lifting up the governor spool which contacts the governor shaft;...

  • Page 26: Linkage Assembly/Disassembly

    Linkage Assembly/Disassembly Speed Controls NOTES This engine has an adjustable speed control. The solid link is always connected from the throttle lever Never exceed the manufacturer’s WARNING on the carburetor to the lower hole on the governor lever. recommended speeds. Failure to do so may cause equipment damage and could The shorter bend has to be toward the governor.

  • Page 27: Chapter 4 Starters

    Chapter 4 Starters Disassembly and Inspection Reinstall Retainer Pin Remove the rewind assembly from the engine. 1/8"(3.2 mm) From Top Use the handle to pull a length of rope out. Tie a temporary knot in the exposed rope. Untie the knot in handle or pry out the staple. Slowly allow the rope to fully retract into the starter housing.

  • Page 28: Stylized Rewind Starter With Plastic Retainer

    Stylized Rewind Starter with Plastic Retainer Wedge Retainer Disassembly and Inspection Remove the rewind assembly from the engine. Starter Use the handle to pull a length of rope out. Housing Tie a temporary knot in the exposed rope. Untie the knot in handle or pry out the staple. Starter Pulley Slowly allow the rope to fully retract into the starter Spring &...

  • Page 29: 12 Volt Electric Starters

    12 Volt Electric Starters Removal Parts List: Remove face plate, air cleaner assembly and gas Retainer ring tank. Dust washer Compress plastic grommet and pull it out of the Drive nut blower housing. Pinion driver Slide the wire through slot, being careful not to cut Gear the wire insulation.

  • Page 30: Check Brushes

    Armature Check Check Brushes If commutator bars are glazed or dirty, they can be Before disassembling armature, check brushes for wear. turned down in a lathe. • Make sure brushes are not worn to the point where brush wire bottoms out in the slot of •...

  • Page 31: Assembly

    Assembly 1. Attach the ground wire prior to assembling the electric Starter Prongs starter to the baffle. 2. Attach the black ground wire to the electric starter through bolt so the wire extends between the two adjacent end cap prongs. 3.
  • Page 32 NOTES 695578...

  • Page 33: Chapter 5 Flywheels

    Chapter 5 Flywheels General Information Disconnect negative battery cable WARNING before servicing. If the positive battery cable contacts ground with the negative cable connected it may cause a battery explosion which could result in death or serious injury. This engine uses one of two types of flywheels. High Inertia Flywheel The first type is cast iron.

  • Page 34: Cored Holes

    Doing so Install into Keyway may result in Breather cover damage. as shown Install flywheel Install the fan onto the flywheel so the Tecumseh logo on the fan is on the magnet side of the flywheel. F O R Magnet Place starter cup into position and torque the flywheel nut to specification.

  • Page 35: Brake System

    Brake System Stopping the Engine Tecumseh’s Flywheel Brake System provides consumer In the stop position the brake pad is applied to the safety by shutting down the engine and lawn mower inside edge of the flywheel; at the same time the ignition blade within seconds after the operator releases an system is grounded out.

  • Page 36: Wiring Diagrams

    Brake Pad Replacement Wiring Diagrams (Electric Start Systems). All wiring beyond the 1. If equipped with electric starter, locate wire routing connectors on the engine are supplied by the equip- through blower housing. Compress the grommet and ment manufacturer. Check all terminals and connec- pull it out of the blower housing.

  • Page 37: Brake Control Lever Replacement

    Brake Control Lever Replacement Control Switch Mark hole that spring is installed into baffle. The brake lever must close the switch before the starter can be engaged. Remove “E” clip from brake lever shaft. Disconnect battery from circuit before making check. Lift brake control lever and unhook link.

  • Page 38: Chapter 6 Alternator

    Chapter 6 Alternator Alternator Troubleshooting Electric Start Engines The 350 Milliampere charging system consists of a The following is a list of possible problems and causes. single alternator coil mounted to one side of the solid Dead Battery state module. Extended storage without charging Alternator Solid State Module...

  • Page 39: Chapter 7 Ignition

    Chapter 7 Ignition Solid State Ignition Tecumseh’s solid state capacitor discharge ignition (CDI) is an all electronic ignition system and is encap- sulated in epoxy for protection against dirt and mois- ture. Solid State Ignition Operation As the magnets in the flywheel rotate past the charge coil, electrical energy is produced in the module.

  • Page 40: Ignition Timing

    The proper air gap setting between magnets and the laminations on CDI systems is .0125'’ (.313 mm). Install gauge, Tecumseh Part No. 670297 between the magnets and laminations and tighten mounting screws to a torque of 30-40 inch pounds (3-4.5 Nm). Recheck gap setting to make certain there is proper clearance between the magnets and laminations.

  • Page 41: Piston And Rings

    Replace rings in sets and always stagger ring gaps. When installing new rings, deglaze cylinder wall, NOTE using a commercially available deglazing tool. Emission Compliant VLV uses this Use a ring expander to remove and replace rings. ring package. Do not spread the piston rings CAUTION too wide.

  • Page 42: Connecting Rods

    Connecting Rods Match Marks Do not attempt to straighten bent CAUTION connecting rods. Doing so will damage the cylinder and piston beyond repair. Match marks on connecting rods must always align and must face outward toward the mechanic when installed in an engine.

  • Page 43: Chapter 9 Cylinders And Cylinder Heads

    Chapter 9 Cylinders and Cylinder Heads Cylinder Service Cylinder Heads Check cylinder for dirty, broken or cracked fins, worn or Check cylinder heads for warpage by placing on a flat scored bearings or scored cylinder bore surface, and surface. If the cylinder head gasket surface is warped in warped head mounting surface.

  • Page 44: Chapter 10 Crankshafts, Camshafts And Lubrication

    Chapter 10 Crankshafts, Camshafts and Lubrication Crankshafts Camshaft Removal Align timing marks to relieve valve train pressure. Lift Do not attempt to straighten a CAUTION bent crankshaft. Doing so will out cam. damage gears, and result in engine failure. Inspect crankshaft for worn, scratched or damaged bearing surfaces, out-of-round or flat spots on the journal area, or a bent P.T.O.

  • Page 45: Lubrication System

    Lubrication System An eccentric on the camshaft works the plunger in the All Tecumseh Vertical shaft 4-Cycle engines use a barrel back and forth, forcing oil up the center of the positive displacement plunger oil pump to pump oil from camshaft.
  • Page 46 Condensed oil vapors are returned to the crankcase by The breather compartment is located under the means of the oil return hole. The oil return hole is flywheel. A check valve allows excess crankcase opened and closed in the cylinder by the piston. pressure to be vented through the element and out the breather tube.

  • Page 47: Chapter 11 Valves, Lifters, Spring And Valve Seats

    Chapter 11 Valves, Lifters, Spring and Valve Seats GeneraI Information Valves must be in good condition, proper sealing and proper gap must be maintained for full power, easy Exhaust starting and efficient operation. Valve Valve Removal To remove valves, use a commercially available valve spring compressor.

  • Page 48: Valve Adjustments

    “V” block to hold correct oversize dimension. the valve square on grinding wheel, grinding to the proper .004" to .008” (.101 - .203 mm) clearance. Reamers are available through your Tecumseh parts NOTE suppliers. Some emissionized engines use intake valve stem seals See Tool Section for correct part numbers.

  • Page 49: Chapter 12 Oil Seal Service And Mounting Flange

    Chapter 12 Oil Seal Service and Mounting Flange Oil Seal Service NOTES If crankshaft is out of engine, remove old oil seals by Drain oil from crankcase. tapping them out with a screwdriver or punch from the If the crankshaft end is rusty or pitted, polish the inside.

  • Page 50: Chapter 13 Troubleshooting

    Chapter 13 Troubleshooting The following charts can be helpful in locating the most common troubles associated with gasoline engines; Pos- sible causes and remedies are listed below. Refer to the appropriate sections in this Technician's Handbook for further detail of procedures. Table 1.

  • Page 51: Table 1. 4-Cycle Engine Troubleshooting Chart

    Table 1. 4-Cycle Engine Troubleshooting Chart (Continued) Engine Misses Under Load Remedy and Reference Cause Spark plug fouled. Replace spark plug. Improper spark plug gap. Regap spark plug. Spark plug porcelain cracked. Replace spark plug. Improper valve clearance. Adjust valve clearance to recommended specifications. Weak valve spring.
  • Page 52 Table 1. 4-Cycle Engine Troubleshooting Chart (Continued) Engine Uses Excessive Amount of Oil Remedy and Reference Cause Oil level too high. To check level turn dipstick cap tightly into receptacle for accurate level reading. Oil filler cap loose or gasket damaged causing Replace ring gasket under cap and tighten tube securely.
  • Page 53 Table 1. 4-Cycle Engine Troubleshooting Chart (Continued) Oil Seal Leaks (Continued) Remedy and Reference Cause Bent crankshaft causing seal to leak. Check crankshaft for straightness and replace if necessary. New seal damaged upon installation. Use proper seal protector tools and methods for installing another new seal.

  • Page 54: Table 2. Carburetor Malfunction Check Points

    Table 2. Carburetor Malfunction Check Points Corrections Trouble Engine will not start 1, 2, 3, 4, 5, 6, 8, 14, 15, 17, 18, 19 Engine will not accelerate 2, 3, 17 Engine hunts (at idle or high speed) 3, 4, 8, 9, 14, 20, 21, 22 Engine will not idle 4, 8, 9, 14, 20, 21, 22 Engine lacks power at high speed...

  • Page 55: Table 3. Troubleshooting 12 Volt Starters

    Table 3. Troubleshooting 12 Volt Starters Problem Probable Cause Remedy and Reference Does not function Weak or dead battery. Check charge and/or replace battery. Loose or faulty electrical connections. Correct. Corroded battery terminals and/or Clean terminals and/or connections. electrical connections. Load on engine.
  • Page 56 Table 3. Troubleshooting 12 Volt Starters (Continued) Problem Probable Cause Remedy and Reference Motor stalls under load. Shorted field coil. Correct, or replace housing assembly. Shorted or open armature. Replace armature. Intermittent operation. Break in electrical circuit. Disconnect ignition cut-off wire at the engine. Crank engine, if spark, check ignition switch, safety switch and interlock switch.

  • Page 57: Chapter 14 Engine Specifications

    Chapter 14 Engine Specifications VLV40 VLV50, 55, 60, 65, 6.75 VLV126 Displacement 11.19 183.4 cc 12.6 207 cc Stroke 2.047 51.993 mm 2.047 51.993 mm Bore 2.6390 67.031 mm 2.796 71.018 mm 2.6380 2.795 70.993 mm Air Gap Dimension Ignition .0125 .30 mm .0125...

  • Page 58: Torque Specifications

    Torque Specifications Inch-Lbs. Governor Rod Clamp to Lever 7-12 1.4 - 1.4 Breather Cover 40-50 4.5 - 5.7 Valve Box Cover 25-35 3.1 - 4.0 Connecting Rod 95-110 10.7 - 12.4 Cylinder Head 180-220 20.3 - 25 Mounting Flange or Cylinder Cover 100-130 11.3 - 14.7 Housing Baffle to Cylinder...

  • Page 59: Chapter 15 Education Materials And Tools

    Covers the diagnosis and repair of Tecumseh 2-cycle engines. Except the TC Engine and TVS840. 692738 Assists in the use and understanding of the Tecumseh 692509 Master Parts Manual. Illustrates time saving features Covers the diagnosis and repair of the Tecumseh incorporated into the manual.

  • Page 60: Tool Kit

    Tool Kit 670195E Kit contains tools for 2- and 4-cycle engines. Includes all items on this page but items may be purchased separately. 670305 Strap Wrench 670294 670292 670293 670306 Flywheel Puller 670299 Flywheel Puller 670315A Valve Spring Compressor For: OVM, OVXL 120-125, OHV 11-17 670297 670321 Air gap Gauge...
  • Page 61 TORX DRIVERS FLYWHEEL KNOCK-OFF TOOL Torx 8 670334 Torx 10 670333 Torx 15 670323 Torx 20 670324 Torx 25 670319 No. 670169 Torx 30 670320 VIBRATION TACHOMETER No. 670156 - Vibration tachometer. No. 670117 - Ring Expander No. 670339 - E-5 Socket No.

  • Page 62: Sears Craftsman Cross Reference Chart

    Chapter 16 Sears Craftsman Cross Reference Chart 143.434112 VLV55-501004 143.976608 VLV66-502511B 143.434252 VLV55-501008 143.976610 VLV66-502512B 143.945500 VLV55-501004A 143.976612 VLV66-502513D 143.956000 VLV60-502003A 143.986008 VLV60-502055D 143.956002 VLV60-502004A 143.986516 VLV65-502521C 143.956006 VLV60-502012A 143.986600 VLV66-502505C 143.966000 VLV60-502015B 143.986700 VLV66-502514C 143.966006 VLV60-502023B 143.986706 VLV66-502515C 143.966008 VLV60-502024B 143.986708 VLV66-502516C...

  • Page 63: Decimal/Fraction Conversions

    Decimal/Fraction Conversions .016 = 1/64 .516 = 33/64 .031 = 1/32 .531 = 17/32 .047 = 3/64 .547 = 35/64 .063 = 1/16 .563 = 9/16 .078 = 5/64 .578 = 37/64 .094 = 3/32 .594 = 19/32 .109 = 7/64 .609 = 39/64 .125 = 1/8 .625 = 5/8...
  • Page 64 NOTES 695578 16-3...

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