Briggs & Stratton Vanguard 10V300 Repair Manual
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Briggs & Stratton Vanguard 10V300 Repair Manual

Single cylinder ohv air cooled engine
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REPAIR MANUAL
Vanguard
Single Cylinder OHV
®
Air Cooled Engine Repair
10V300/12V300

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Summary of Contents for Briggs & Stratton Vanguard 10V300

  • Page 1 REPAIR MANUAL Vanguard Single Cylinder OHV ® Air Cooled Engine Repair 10V300/12V300...
  • Page 3 Foreword This manual was written to assist engine technicians and service personnel with the maintenance and repair procedures for Briggs & Stratton® engines. It assumes that persons using this manual have been properly trained and are familiar with the service procedures for these products, including the proper use of required tools and the application of appropriate safety practices.
  • Page 4 This engine repair manual includes the following engine models: • MODEL 10V300 • MODEL 12V300 NOTE: Some models have limited service parts. Review the Illustrated Parts List for part availability before conducting any service work. NOTE: The images in this document are representative and may differ according to model.
  • Page 5   HOW TO USE THIS MANUAL  Besides describing the service maintenance tasks and the intervals at which they are to be performed, two basic levels of service are presented in this manual: engine top end service and engine bottom end service. The manner in which these instructions are used depends upon the tasks to be performed and the level of disassembly required. ...
  • Page 7 SECTION 1 – SAFETY AND GENERAL INFORMATION SECTION 2 – MAINTENANCE SECTION 3 – TROUBLESHOOTING/SPECIAL TOOLS SECTION 4 – REMOVE EXTERNAL ASSEMBLIES SECTION 5 – DISASSEMBLE ENGINE SECTION 6 – SERVICE ENGINE SUBASSEMBLIES SECTION 7 – ASSEMBLE ENGINE SECTION 8 – INSTALL EXTERNAL ASSEMBLIES SECTION 9 –...
  • Page 9 SECTION 1 – SAFETY AND GENERAL INFORMATION SAFETY ------------------------------------------------------------------------------------------------------------------------------------------------ 4 Safety Alert Symbol and Signal Words ---------------------------------------------------------------------------------------------------4 Hazard Symbols and Meanings ------------------------------------------------------------------------------------------------------------ 4 General Safety Messages --------------------------------------------------------------------------------------------------------------------4 GENERAL INFORMATION ------------------------------------------------------------------------------------------------------------------------7 Engine Identification --------------------------------------------------------------------------------------------------------------------------- 7 Fuel Recommendations -----------------------------------------------------------------------------------------------------------------------7 High Altitude ------------------------------------------------------------------------------------------------------------------------------------- 7 Oil Recommendations ------------------------------------------------------------------------------------------------------------------------- 7...
  • Page 10 SAFETY This manual contains safety information that will:  General Safety Messages • Make you aware of hazards associated with engines.  Prior to work, read and understand the section(s) of this • Inform you of the risk of injury associated with those manual that pertain to the job.
  • Page 11 When Storing Fuel or Equipment with Fuel In Tank • Store away from furnaces, stoves, water heaters, WARNING clothes dryers, or other appliances that have pilot Fuel and its vapors are extremely flammable and lights or other ignition source because they could explosive which could cause burns, fire or explosion ignite fuel vapors.
  • Page 12 • Direct-coupled equipment components such as, but • Use only correct tools. not limited to, blades, impellers, pulleys, sprockets, • Do not tamper with governor spring, links or other etc., must be securely attached. parts to increase engine speed. • Replacement parts must be of the same design and installed in the same position as the original parts.
  • Page 13 GENERAL INFORMATION Engine Identification High Altitude See Figure 1 for location of engine identification. At altitudes over 5,000 feet (1524 meters), a minimum 85 octane / 85 AKI (89 RON) gasoline is acceptable. For carbureted engines, high altitude adjustment is required to remain emissions compliant.
  • Page 14 for the outdoor temperature range expected. Engines on most outdoor power equipment operate well with 5W-30 Synthetic oil. For equipment operated in hot ® temperatures, Vanguard 15W-50 Synthetic oil provides the best protection.

  • Page 15: Table Of Contents

    SECTION 2 – MAINTENANCE MAINTENANCE -------------------------------------------------------------------------------------------------------------------------------------10 Maintenance Schedule ---------------------------------------------------------------------------------------------------------------------- 10 Change Engine Oil/Check Engine Oil Level -------------------------------------------------------------------------------------------10 Clean Muffler, Rewind Starter Finger Guard, and Controls ----------------------------------------------------------------------- 11 Clean/Inspect Muffler and Spark Arrester ----------------------------------------------------------------------------------------------12 Change 6:1 Gear Reduction Oil (If Equipped) ---------------------------------------------------------------------------------------- 13 Check/Change Non Integrated 2:1 Gear Reduction Oil (If Equipped) ---------------------------------------------------------- 13 Clean/Replace Air Filter ---------------------------------------------------------------------------------------------------------------------14 Clean/Replace Low Profile Air Filter (If Equipped) ---------------------------------------------------------------------------------- 14...

  • Page 16: Maintenance

    MAINTENANCE Maintenance Schedule After First 5 Hours • Change Engine Oil Every 8 Hours or Daily • Check Engine Oil Level • Clean Muffler, Rewind Starter Finger Guard, and Controls Every 100 Hours or Annually • Clean/Inspect Muffler and Spark Arrester •...

  • Page 17: Clean Muffler, Rewind Starter Finger Guard, And Controls

    15. Install oil fill cap into valve cover. Tighten oil fill cap securely, but do not over-tighten.  NOTE: If using the dipstick oil plug, the foregoing instructions still apply, but with the following differences: screw plug completely into bore (E) before checking if engine oil level is at or near the high mark (F), and if adding oil, use a funnel and a short length of plastic tubing (G) for best results.

  • Page 18: Clean/Inspect Muffler And Spark Arrester

    NOTE: Rewind starter may be installed in the 2 o'clock, 8 o'clock, 10 o'clock, or 12 o'clock positions. 11. Loosely install three hex flange screws to fasten rewind starter to blower housing. NOTE: To ensure that pawls evenly engage flywheel starter cup, pull starter rope, tighten hex flange screws until snug, and then release starter rope.

  • Page 19: Change 6:1 Gear Reduction Oil (If Equipped)

    B. If stamped guard, start three screws to install spark arrester and muffler deflector. Tighten screws to 25-35 lb-in (2.8-4 N-m). C. If wire guard, install single screw to fasten muffler deflector/spark arrester to muffler. Tighten screw to 8-12 lb-in (0.9-1.4 N-m). 10. Install spark plug wire onto spark plug terminal. Change 6:1 Gear Reduction Oil (If Equipped) 1.

  • Page 20: Clean/Replace Air Filter

    14. Install spark plug wire onto spark plug terminal. 15. Start and run engine for one minute. Check for oil leaks while engine is running. 16. Dispose of used oil at a proper waste disposal or recycling center. Clean/Replace Air Filter 1.

  • Page 21: Clean/Gap/Replace Spark Plug

    8. Install air filter cartridge into air cleaner base. 8. Install spark plug wire onto spark plug terminal. 9. Install air cleaner cover onto air cleaner base. Move latch to lock cover. 10. Install duckbill air valve on air inlet port of air cleaner cover. Replace duckbill air valve if damaged or missing.
  • Page 22 14. Unthread fuel filter (I) and remove O-ring (J) from fuel filter fitting. 15. Inspect fuel filter for dirt and debris. Clean or replace as necessary. 16. Inspect O-ring for cuts, tears, or general deterioration. Replace as necessary. 17. Install O-ring onto fuel filter fitting. Verify O-ring is fully seated in groove.

  • Page 23: Clean Carburetor Sediment Bowl

    7. Install fuel filter screen and O-ring into sediment bowl. Clean Carburetor Sediment Bowl Install sediment bowl onto fuel shutoff valve. Tighten sediment bowl to 20-25 lb-in (2.3-2.8 N-m). 8. Install spark plug wire onto spark plug terminal. WARNING Wrap shop towel around sediment bowl to catch any Clean Air Cooling System fuel leakage.

  • Page 24: Check/Adjust Valve Clearance

    8. If adjustment is necessary to obtain proper clearance, proceed as follows: A. Loosen set screw (H) and turn rocker ball nut (I) as necessary. B. Holding rocker ball nut to prevent rotation, tighten set screw to 60-80 lb-in (6.8-9 N-m). C.
  • Page 25 SECTION 3 – TROUBLESHOOTING/SPECIAL TOOLS TROUBLESHOOTING ---------------------------------------------------------------------------------------------------------------------------- 20 Check Ignition ----------------------------------------------------------------------------------------------------------------------------------20 Check Carburetion ----------------------------------------------------------------------------------------------------------------------------21 Check Compression --------------------------------------------------------------------------------------------------------------------------21 Check Low Oil Sensor System ----------------------------------------------------------------------------------------------------------- 22 Check Breather Valve ----------------------------------------------------------------------------------------------------------------------- 22 SPECIAL TOOLS ---------------------------------------------------------------------------------------------------------------------------------- 23...

  • Page 26: Troubleshooting

    TROUBLESHOOTING General Complaints Check Ignition Most complaints concerning engine operation include one or more of the following: 1. Move to step 2 if engine does not start. If engine runs, but misses, move to step 9.  • Will not start •...

  • Page 27: Check Carburetion

    6. A dry spark plug may indicate: • Leaking carburetor or intake manifold gaskets WARNING • Gummy or dirty carburetor, fuel filter, fuel lines, or  Be sure there is no fuel or fuel vapors present fuel tank which, if spark ignited, can cause a fire or explosion •...

  • Page 28: Check Low Oil Sensor System

    Check Low Oil Sensor System Engine Does Not Start 1. Verify that engine oil level is within the cross hatch pattern on the dipstick. 2. See Figure 19. If engine oil level is satisfactory, disconnect one-place wire connector between oil sensor module and oil sensor in crankcase (A).

  • Page 29: Special Tools

    SPECIAL TOOLS 11. Leakdown Tester (Part No. 19545) 1. Piston Ring Compressor (Part No. 19070) 12. Master Seat Cutter Kit (Part No. 19547) 2. Flywheel Puller (Part No. 19203) 13. Spark Plug Wrench (Part No. 19576S) 3. Valve Lapping Tool (Part No. 19258) 14.
  • Page 31 SECTION 4 – REMOVE EXTERNAL ASSEMBLIES REMOVE EXTERNAL ASSEMBLIES -------------------------------------------------------------------------------------------------------- 26 Preliminary Instructions ----------------------------------------------------------------------------------------------------------------------26 Air Cleaner --------------------------------------------------------------------------------------------------------------------------------------26 Low Profile Air Cleaner (If Equipped) --------------------------------------------------------------------------------------------------- 27 Starter Motor/Regulator (If Equipped) --------------------------------------------------------------------------------------------------- 28 Fuel Tank --------------------------------------------------------------------------------------------------------------------------------------- 28 Fuel Pump/Hoses (If Equipped) ---------------------------------------------------------------------------------------------------------- 30 Engine Cover ---------------------------------------------------------------------------------------------------------------------------------- 30 Muffler -------------------------------------------------------------------------------------------------------------------------------------------- 31 Control Bracket/Governor Lever ---------------------------------------------------------------------------------------------------------- 31...

  • Page 32: Remove External Assemblies

    REMOVE EXTERNAL ASSEMBLIES F. Tighten float bowl drain screw to 8-12 lb-in Preliminary Instructions (0.9-1.3 N-m). G. Remove 1/8 inch tubing from float bowl fitting. 1. Start and run engine until fuel tank is empty. If the 2. Remove spark plug wire from spark plug terminal. engine will not start, drain fuel tank as follows: Secure spark plug wire to prevent unintentional contact with spark plug terminal.

  • Page 33: Low Profile Air Cleaner (If Equipped)

    6. Remove breather hose (I) from port on air cleaner 6. Remove two hex flange nuts (G) to release bracket base. (H) from standoffs (I). 7. Remove two hex flange nuts (J) to release air cleaner 7. Remove two standoffs from carburetor studs. base from carburetor mounting studs.

  • Page 34: Starter Motor/Regulator (If Equipped)

    Starter Motor/Regulator (If Equipped) 1. Cut cable strap to release two regulator wire connectors from starter solenoid housing. 2. See Figure 26. Disconnect two-place wire connector (A) between stator and regulator. 3. Remove hex nut (B), lock washer, and flat washer from starter solenoid post.
  • Page 35 NOTE: For best access to screw, move throttle 4. If equipped, remove key switch panel (C) from fuel control lever left to the FAST position and use a 8 mm tank studs. Disconnect key switch harness connector socket with extension. from key switch.

  • Page 36: Fuel Pump/Hoses (If Equipped)

    C. Remove hose from crankcase cover fitting (D). If Fuel Pump/Hoses (If Equipped) necessary, remove other end from pulse pump fitting (E). 1. Squeeze tangs to move each hose clamp away from D. Remove two hex flange screws (F) to release fuel fitting, and then proceed as follows: pump (G) from bracket (H).

  • Page 37: Muffler

    3. Remove Nyloc nut (D), flat washer (E), and square- Muffler head screw (F) from governor lever (G). Remove governor lever from governor crank. 1. See Figure 32. Remove hex flange screw (A) to release muffler tamper bracket (B) from cylinder NOTE: Do not remove spring clip from governor head, if equipped.

  • Page 38: Carburetor

    Carburetor 1. See Figure 34. Using a 4 mm hex socket, alternately loosen and remove two carburetor studs (A). If end of stud will not accept a 4 mm hex socket due to damage or wear, proceed as follows: A. Retrieve the two hex flange nuts removed from the studs during air cleaner removal.

  • Page 39: Blower Housing

    NOTE: Note orientation of the rewind starter before Low Oil Sensor Module (If Equipped) removal. Rewind starter may be installed in the 2 o'clock, 8 o'clock, 10 o'clock, or 12 o'clock positions. NOTE: If engine is equipped with electric start, oil sensor module is removed with starter motor/regulator.

  • Page 40: Gear Reduction Unit (If Equipped)

    8. Remove four hex flange screws (I) to release gear case from crankcase cover. 9. Remove gasket (J) from crankcase cover. Discard gasket. Integrated 2:1 Gear Reduction Unit Gear Reduction Unit (If Equipped) 1. See Figure 41. Remove five screws (A) to release gear cover (B) from crankcase cover.

  • Page 41: Non Integrated 2:1 Gear Reduction Unit

    6. Remove crankshaft screw (H) and lock washer (I) Non Integrated 2:1 Gear Reduction Unit from engine crankshaft. 1. See Figure 42. Remove dipstick (A) from the oil filler 7. Remove clutch (J), chain (K), and PTO shaft hole. assembly (L). 2.
  • Page 43 SECTION 5 – DISASSEMBLE ENGINE TOP END DISASSEMBLY -----------------------------------------------------------------------------------------------------------------------38 BOTTOM END DISASSEMBLY ---------------------------------------------------------------------------------------------------------------- 40...
  • Page 44 TOP END DISASSEMBLY NOTE: A second hex flange screw was removed with 1. See SECTION 4 - REMOVE EXTERNAL the blower housing, while a third screw was removed ASSEMBLIES. with the control bracket. 2. See Figure 43. Remove two hex flange screws (A) to 4.
  • Page 45 wooden dowel through the spark plug hole until A. Remove all loose debris by hand. seated at the top of the piston. B. Remove dust and dirt with a soft bristle brush and C. Rotate engine in the same direction until the a portable hand held vacuum.
  • Page 46 BOTTOM END DISASSEMBLY B. Pinch strap between heel of wrench and flywheel 1. See TOP END DISASSEMBLY in this section. as shown. 2. See Figure 45. Obtain Strap Wrench (Part No. C. Holding tool down by the handle, loosen flywheel 19433), 21 mm socket, and breaker bar.
  • Page 47 F. Move top hex nuts down puller screws until firm contact is made with top of puller. G. Move bottom hex nuts down puller screws until firm contact is made with flywheel. H. Verify that tool is square, and not slanting or leaning.
  • Page 48 13. See Figure 49. Rotate crankshaft (A) to align timing marks (B) on crankshaft gear tooth and camshaft gear root. NOTE: Valve tappets are now clear of the camshaft lobes. 14. Remove camshaft (C) from bearing bore in crankcase. 15. Remove valve tappets from crankcase. Tag each tappet as it is removed, so that it can be installed in its original location when the engine is assembled.
  • Page 49 21. Remove crankshaft from crankcase. 22. See the following topics under SECTION 6 - SERVICE ENGINE SUBASSEMBLIES: • PISTON AND CONNECTING ROD • FLYWHEEL, CRANKSHAFT AND CAMSHAFT • CRANKCASE AND CRANKCASE COVER.
  • Page 51 SECTION 6 – SERVICE ENGINE SUBASSEMBLIES CYLINDER HEAD ----------------------------------------------------------------------------------------------------------------------------------47 Disassembly ------------------------------------------------------------------------------------------------------------------------------------ 47 Cleaning ----------------------------------------------------------------------------------------------------------------------------------------- 47 Inspection --------------------------------------------------------------------------------------------------------------------------------------- 48 Cylinder Head ---------------------------------------------------------------------------------------------------------------------------- 48 Valve Guides ----------------------------------------------------------------------------------------------------------------------------- 48 Valve Seats ------------------------------------------------------------------------------------------------------------------------------- 49 Valves ---------------------------------------------------------------------------------------------------------------------------------------49 Valve Springs -----------------------------------------------------------------------------------------------------------------------------50 Valve Spring Retainers ---------------------------------------------------------------------------------------------------------------- 50 Tappets, Push Rods, and Rocker Arms ------------------------------------------------------------------------------------------ 50 Muffler Studs ------------------------------------------------------------------------------------------------------------------------------51 Assembly ---------------------------------------------------------------------------------------------------------------------------------------- 51...
  • Page 52 Crankcase Cover ------------------------------------------------------------------------------------------------------------------------------60 PTO Bearing/Oil Seal ------------------------------------------------------------------------------------------------------------------ 60 Cleaning ----------------------------------------------------------------------------------------------------------------------------------------- 60 Inspection --------------------------------------------------------------------------------------------------------------------------------------- 61 Deglaze (Recondition) Cylinder Bore ---------------------------------------------------------------------------------------------- 62 Hone (Resize) Cylinder Bore ---------------------------------------------------------------------------------------------------------62 Clean Crankcase and Cylinder Bore -----------------------------------------------------------------------------------------------63 Assembly ---------------------------------------------------------------------------------------------------------------------------------------- 63 Crankcase ---------------------------------------------------------------------------------------------------------------------------------------63 MAG Bearing/Oil Seal ------------------------------------------------------------------------------------------------------------------63 Low Oil Sensor (If Equipped) -------------------------------------------------------------------------------------------------------- 64 Governor Crank -------------------------------------------------------------------------------------------------------------------------- 65 Crankcase Cover ------------------------------------------------------------------------------------------------------------------------------65...

  • Page 53: Cylinder Head

    CYLINDER HEAD Disassembly 1. Pack shop towels into the combustion chamber and place cylinder head on bench with the combustion chamber side down. 2. Remove exhaust valve as follows: A. See Figure 53. Remove valve cap (A). B. Using thumb pressure, press down on valve spring retainer (B) to disengage from valve stem groove.

  • Page 54: Inspection

    a worn fine wire brush. Scraping may result in scratches or nicks.  2. To soften stubborn deposits, soak the cylinder head in a suitable chemical solution or other carbon and gum dissolving agent. Repeat steps 1-2 as necessary.      NOTE: Do not use glass or sand to bead blast surfaces exposed to the engine oil.

  • Page 55: Valve Seats

    2. To verify cleanliness, lightly hone bore using a suitable valve guide hone and then scrub with a valve guide cleaning brush to remove any dirt or debris. 3. Measure the inside diameter using an inside ball micrometer or plug gauge. Replace the cylinder head if the measurement is 0.220 inches (5.592 mm) or more.

  • Page 56: Valve Springs

    tool approximately 20° back and forth a few B. See Figure 57. Install the 60° cutter on the pilot times.  to make the bottom-narrowing cut. Rotate the cutter three of four turns, so that it cuts all the H. Remove valve from the cylinder head and way around the valve seat. ...

  • Page 57: Muffler Studs

    concave wear where rocker arms contact the push rod ends. Replace the rocker arm if excessive wear is found at either location, or if pitted, deformed, or scored. Muffler Studs 1. Inspect muffler studs. Replace studs if broken, bent, or if severe thread damage is observed. 2.
  • Page 58 Lightly tap the end of the valve stem once or as it is installed. Work the valve back and forth in twice with a soft mallet to ensure that valve spring the bore to verify that it slides smoothly and seats retainer is tightly seated in the valve stem groove.

  • Page 59: Piston And Connecting Rod

    PISTON AND CONNECTING ROD Disassembly 1. See Figure 60. Insert small pick into pick lock groove and pull piston pin lock ring out of pin boss groove. Discard lock ring. CAUTION Always wear proper eye protection when removing piston pin lock ring. Slippage can propel the ring with enough force to cause eye injury.

  • Page 60: Cleaning

    Cleaning Piston 1. Do not sand blast or glass bead blast piston. Bead blasting rounds the ring lands and will result in high oil consumption and blow-by of exhaust gases. Blow- by of exhaust gases contaminates the engine oil supply, and reduces engine efficiency by weakening the combustion seal necessary for efficient transfer of energy to the piston.

  • Page 61: Piston Rings

    G. Repeat steps 1(B) thru 1(D) using rails of new oil B. Since the grooves wear unevenly, repeat this control ring. Do not use the ring if the end gaps check at several locations around the piston ring are 0.074 inches (1.89 mm) or more. groove circumference.

  • Page 62: Assembly

    2. See Figure 68. Place piston over connecting rod end, so that the notch on the piston crown is on the same side as the word MAG on the connecting rod shank. 3. Insert piston pin through piston pin bore and upper connecting rod bearing.
  • Page 63 ring gap. Damaged or distorted rings result in blow- 11. Rotate piston rings using the palms of both hands. by of exhaust gases, increased oil consumption, and Verify that the rings rotate freely without sticking. lower service life of valves and other components. 12.

  • Page 64: Flywheel, Crankshaft And Camshaft

    FLYWHEEL, CRANKSHAFT AND CAMSHAFT Cleaning Crankshaft 1. See Figure 73. Carefully remove crankshaft end 1. Thoroughly clean parts in a non-volatile cleaning play shims (A), if present. Count shims as they are solution or solvent. Follow up with a thorough wash in removed to be sure of installing the correct number hot soapy water.

  • Page 65: Camshaft

    Camshaft 1. See Figure 74. Check camshaft gear (A) for worn, cracked, chipped, or missing teeth. 2. Check operation of yoke on Mechanical Compression Release (MCR) mechanism (B). NOTE: Press yoke to the OPEN position, and then verify that it returns to the fully CLOSED position when released.

  • Page 66: Crankcase And Crankcase Cover

    CRANKCASE AND CRANKCASE COVER Disassembly Crankcase Cover Crankcase PTO Bearing/Oil Seal 1. Remove and discard oil seal from crankcase cover Governor Crank bearing bore, if present. Exercise care to avoid scratching bearing bore during removal. 1. Remove spring clip from hole in governor crank. Remove flat washer from crankcase boss.

  • Page 67: Inspection

    7. Using Magnaflux Dye Penetrant, inspect the cylinder Inspection bore for cracks. If no cracks are found, thoroughly wash cylinder to remove traces of dye. 1. Inspect governor gear as follows: 8. Check the cylinder to cylinder head mating surface for warpage or distortion.

  • Page 68: Deglaze (Recondition) Cylinder Bore

    4. Place hone drive shaft in chuck of portable, variable speed drill and tighten.  5. Using a suitable honing oil, liberally lubricate cylinder bore and finishing stones.  6. Hone cylinder bore using a drill speed of approximately 200 RPM at 40-60 strokes per minute.  7.

  • Page 69: Clean Crankcase And Cylinder Bore

    2. Obtain a three blade rigid hone with 220 grit 3. Thoroughly rinse cylinder bore with hot running water. aluminum oxide stones. 4. Repeat washing and rinsing until all traces of honing 3. To prevent damage to stones, check the top and grit are gone.

  • Page 70: Low Oil Sensor (If Equipped)

    NOTE: Exercise care to avoid any contact with the governor gear. Damage to the governor gear requires crankcase replacement. 9. Inspect the bearing for damage or distortion. 10. See Figure 81. Use your index finger to manually rotate the bearing in both directions. Verify that bearing rotates freely without roughness, sticking, or unusual noise.

  • Page 71: Governor Crank

    4. See Figure 83. Install two hex flange screws (A) 3. See Figure 84. Install governor cup onto governor to fasten oil sensor to threaded bosses inside gear shaft (A). crankcase. Tighten screws to 50-70 lb-in (5.7-7.9 N- 4. From inside crankcase, insert governor crank thru hole at top of crankcase (B).
  • Page 72 12. If oil seal is required, support crankcase cover on wooden blocks on deck of arbor press with the outside facing upward. 13. Apply a thin film of clean engine oil to oil seal bore and OD of new oil seal. 14.
  • Page 73 SECTION 7 – ASSEMBLE ENGINE BOTTOM END ASSEMBLY --------------------------------------------------------------------------------------------------------------------- 68 TOP END ASSEMBLY --------------------------------------------------------------------------------------------------------------------------- 73...
  • Page 74 BOTTOM END ASSEMBLY 1. Apply a thin film of clean engine oil to MAG bearing oil seal lip. 2. See Figure 90. Verify that governor cup (A) is installed on governor gear shaft. 3. Rotate governor crank, so that paddle (B) is in contact with governor cup.
  • Page 75 A. Using tool wrench, unwind sleeve of piston ring compressor. Do not unwind sleeve too far or tool damage will occur. B. Apply clean engine oil to piston rings, piston skirt, cylinder bore, and inside wall of Piston Ring Compressor. C.
  • Page 76 28. See Figure 94. Apply a bead of liquid gasket 0.071 inches (1.8 mm) thick to crankcase cover. Bead must be a continuous closed loop with an overlap 0.236 inches (6 mm). NOTE: Crankcase cover must be installed within five minutes of liquid gasket application.
  • Page 77 A. Tighten screws to 65-93 lb-in (7-11 N-m) using the sequence shown in Figure 96. B. Tighten screws to 130-186 lb-in (15-21 N-m) using the sequence shown. C. Final tighten screws to 194-278 lb-in (21.9-31.4 N-m) using the sequence shown. NOTE: Failure to step-torque screws in the proper sequence may result in gasket leaks or cause the crankcase cover to warp.
  • Page 78 43. Install flywheel fan (E) onto flywheel, so that the deeper indentation at the back fits over the flywheel magnet. NOTE: Rotate flywheel fan slightly to ensure that two large pegs fully engage threaded flywheel puller holes, while the four small pegs engage blind holes. See Figure 101.
  • Page 79 TOP END ASSEMBLY 1. Verify that mating surfaces of cylinder and cylinder head are clean and dry. Any dust or dirt left on mating surfaces can cause leaks. 2. Verify that two locating pins are present on downside of cylinder deck. Install new locating pins if damaged or missing.
  • Page 80 12. Adjust valve clearance. See SECTION 2 - MAINTENANCE, CHECK/ADJUST VALVE CLEARANCE, steps 6-9. 13. Verify that mating surfaces of cylinder head and valve cover are clean and dry. Any dust or dirt left on mating surfaces can cause leaks. 14.
  • Page 81 SECTION 8 – INSTALL EXTERNAL ASSEMBLIES INSTALL EXTERNAL ASSEMBLIES --------------------------------------------------------------------------------------------------------- 76 Armature -----------------------------------------------------------------------------------------------------------------------------------------76 Low Oil Sensor Module (If Equipped) ---------------------------------------------------------------------------------------------------77 Blower Housing --------------------------------------------------------------------------------------------------------------------------------77 Rewind Starter --------------------------------------------------------------------------------------------------------------------------------- 77 Replace Rewind Starter Rope ------------------------------------------------------------------------------------------------------- 78 Carburetor ---------------------------------------------------------------------------------------------------------------------------------------79 Overhaul Carburetor -------------------------------------------------------------------------------------------------------------------- 80 Control Bracket/Governor Lever ---------------------------------------------------------------------------------------------------------- 81 Muffler -------------------------------------------------------------------------------------------------------------------------------------------- 83 Fuel Pump/Hoses (If Equipped) ---------------------------------------------------------------------------------------------------------- 85 Fuel Tank --------------------------------------------------------------------------------------------------------------------------------------- 85...

  • Page 82: Install External Assemblies

    INSTALL EXTERNAL ASSEMBLIES and armature legs. To set air gap to 0.010-0.014 Armature inches (0.25-0.35 mm), loosen bottom hex flange screw (G) to allow magnet to pull armature legs (H) 1. See Figure 108. Loosely install two hex flange screws against gauge.

  • Page 83: Low Oil Sensor Module (If Equipped)

    Blower Housing 1. See Figure 114. Start four hex flange screws (A) to fasten blower housing (B) to crankcase and engine base. Exercise care to avoid pinching stator and/or armature wires. 2. Using the sequence shown in inset, alternately tighten screws to 80-110 lb-in (9-12.4 N-m). Verify that bottom of blower housing is above or flush with bottom of engine base.

  • Page 84: Replace Rewind Starter Rope

    NOTE: If rope is broken, verify that tension increases when pulley is rotated by hand in a counter-clockwise direction. C. Verify that the rope eyelet in the rewind starter housing is in good condition (without burrs or excessive wear). D. Inspect rope for cuts, breaks, or fraying. If rope replacement is necessary, see Replace Rewind Starter Rope.

  • Page 85: Carburetor

    counter-clockwise direction until spring is tightly wound, then rotate pulley clockwise one turn before aligning pulley hole with rewind starter housing eyelet.  8. Insert rope through pulley hole and rewind starter housing eyelet (J).  9. See Figure 118. Pull rope until knot is seated in pulley recess (K).

  • Page 86: Overhaul Carburetor

    C. Thread second nut onto stud right-side up until it Cleaning and Inspection makes firm contact with the first. D. Rotating outside nut in a clockwise direction, 1. Obtain Carburetor Cleaner (Part No. 100042). tighten stud to specification. NOTE: Remove and set aside all rubber parts or E.

  • Page 87: Control Bracket/Governor Lever

    6. Install hex screw (A) with gasket (B) to fasten float bowl (C) to carburetor body. Tighten screw to 44-62 lb-in (5-7 N-m). 7. Tighten float bowl drain screw (M) to 8-12 lb-in (0.9-1.3 N-m). Control Bracket/Governor Lever NOTE: Exercise care to avoid bending, kinking, or stretching link and springs.
  • Page 88 16. Holding governor lever to prevent movement, use 21. Manually exercise governor lever. Verify that a 4 mm hex socket to rotate governor crank in a governor lever, link, and springs move freely without clockwise direction until it stops (about 1/8 turn). binding, sticking, or contacting blower housing.

  • Page 89: Muffler

    B. Remove dust and dirt with a soft bristle brush and Muffler a portable hand held vacuum. C. Gently scrape away stubborn accumulations of 1. If equipped, inspect muffler deflector/spark arrester dirt and other deposits using a plastic putty knife for dirt, debris, and carbon buildup. Proceed as or stiff bristle brush.
  • Page 90 NOTE: Muffler tamper bracket screw also captures NOTE: Muffler deflector is installed in either the 9 cylinder heat shield. o'clock or the optional 6 o'clock position. 10. Start three hex flange screws with lock washers B. If stamped guard, start three screws to install to fasten wire guard or stamped guard to muffler.

  • Page 91: Fuel Pump/Hoses (If Equipped)

    F. Thread fuel filter into fuel filter fitting. Fuel Pump/Hoses (If Equipped) G. Install fuel filter fitting into fuel tank (D). Tighten fitting to 62-71 lb-in (7-8 N-m). 1. See Figure 125. If removed, orient fuel pump (A) as shown and install two hex flange screws (B) to fasten 9.

  • Page 92: Engine Cover

    NOTE: Exercise care to avoid dropping screw Starter Motor/Regulator (If Equipped) between engine and blower housing. A dropped 1. See Figure 128. Install two locating pins (A) into screw may be caught by the flywheel magnet where threaded holes in crankcase. disassembly would be required to retrieve it.

  • Page 93: Air Cleaner

    15. Install two Phillips screws (K) to fasten regulator to flywheel guard. Alternately tighten screws to 60-80 lb-in (6.8-9 N-m). 16. If equipped with regulator red jumper wire, proceed as follows: A. Install jumper wire (L) ring terminal onto starter solenoid post.

  • Page 94: Low Profile Air Cleaner (If Equipped)

    10. Carefully inspect air filter cartridge. Replace if any 13. Install air cleaner cover (J) onto air cleaner base. damage is observed. Alternately tighten two thumbscrews (K) until snug, but do not over-tighten. 11. Inspect seal (I) for cuts, tears, holes, or general deterioration.
  • Page 95 14. Gently tap air filter cartridge (M) on a hard surface to 18. Inspect foam seal (P)  for damage or general loosen dirt and debris. deterioration. Install foam seal into air cleaner cover. Verify that ends of seal do not overlap after NOTE: Use of pressurized air or solvents will damage installation.

  • Page 96: Gear Reduction Unit (If Equipped)

    Gear Reduction Unit (If Equipped) 6:1 Gear Reduction Unit 1. See Figure 134. Use your index finger to manually rotate the gear case bearing (A) and gear case cover bearing (B) in both directions. Verify that bearings rotate freely without roughness, sticking, or unusual noise.

  • Page 97: Integrated 2:1 Gear Reduction Unit

    NOTE: Verify that vent hole of oil fill/vent plug is F. With the open (lip garter spring) side facing in, facing outside. press on outside edge of oil seal until flush with gear cover. Integrated 2:1 Gear Reduction Unit 3. Verify that PTO bearing oil seal is NOT installed in 1.

  • Page 98: Non Integrated 2:1 Gear Reduction Unit

    • Parts are oriented and stacked correctly as Non Integrated 2:1 Gear Reduction Unit shown at bottom of Figure 136. 1. Use your index finger to manually rotate the PTO • All friction disks are installed on the sprocket shaft bearings in both directions. Verify that bearings shaft splines.

  • Page 100: Final Instructions

    Final Instructions Set Idle and Top No-Load Speeds 1. Obtain the Top No-Load Speed for the engine. 1. Install oil drain plug(s) with sealing washer(s) and Proceed as follows: tighten to 140-200 lb-in (15.8-22.6 N-m). 2. Add engine oil. See SECTION 2 - MAINTENANCE, A.

  • Page 101: Remote Control

    NOTE: Use the internal T25 TORX recess for best A. Insert solder lug of white wire under engine or results. frame bolt for suitable ground (B). 6. Verify that return spring (F) is installed. B. Tightly coil red wire over an insulated section of 7.
  • Page 102 Front 1. See Figure 139. Move the throttle control lever (A) to the FAST position. 2. Hold the cable mounting nut (B) and loosen Phillips screw (C). Rotate nut to accept cable wire. 3. Insert the cable wire through the hole in cable mounting nut, so that it does not extend more than 1/2 inches (12.7 mm) past the exit hole.

  • Page 103: Fixed Speed Control (No Wire Cable)

    5. Install Z-fitting of cable into hole in throttle control 5. Remove top hex flange screw on rewind starter. lever (D). Install screw capturing casing clamp bracket (F). Tighten screw to 25-35 lb-in (2.8-4 N-m). 6. Loosen hex screw (E) on air cleaner elbow. Capture cable sheath in casing clamp.
  • Page 105 SECTION 9 – SPECIFICATIONS SPECIFICATIONS --------------------------------------------------------------------------------------------------------------------------------100 Engine Specifications ---------------------------------------------------------------------------------------------------------------------- 100 Torque Specifications ---------------------------------------------------------------------------------------------------------------------- 100 Standard/Reject Sizes --------------------------------------------------------------------------------------------------------------------- 102...
  • Page 106 SPECIFICATIONS Engine Specifications ENGINE 10V300 12V300 Bore 2.44  in (62 mm) 2.677 in (68 mm) Stroke 2.205 in (56 mm) Displacement 10.3 ci (169 cc) 12.39 ci (203 cc) Compression Ratio 8.5:1 8.4:1 Crankshaft End Play 0.004-0.014 in (0.12-0.35 mm) Crankshaft End Play (Pump Applications) 0.004-0.012 in (0.12-0.30 mm) Oil Capacity...
  • Page 107 FASTENER TORQUE Low Oil Sensor Module Screw (Without Electric Start) 30-80 lb-in (3.4-9 N-m) Low Oil Sensor Module Screw (With Electric Start) 80-110 lb-in (9-12.4 N-m) Low Oil Sensor Screw 50-70 lb-in (5.7-7.9 N-m) Low Oil Sensor Nut 30-50 lb-in (3.4-5.7 N-m) Muffler Stud 40-60 lb-in (4.5-6.8 N-m) Muffler Stud Nut...
  • Page 108 Standard/Reject Sizes ITEM STANDARD SIZE REJECT SIZE CRANKCASE/CYLINDER Cylinder Bore Diameter 10V300 2.441 in (68 mm) 2.444 in (62.0875 mm) or more 12V300 2.677 in (68 mm) 2.681 in (68.0875 mm) or more Camshaft Bearing Bore Diameter 0.552 in (14.009 mm) 0.554 in (14.068 mm) or more Cylinder Bore Out-Of-Round 0.002 in (0.05 mm)
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  • Page 112 BRIGGS&STRATTON, LLC CUSTOMER EDUCATION Milwaukee, WI 53201 USA Copyright ©2020. All rights reserved. VANGUARDPOWER.COM 381584EN (Revision A)

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