RESIDENTIAL PRODUCTS RIDING PRODUCT ENGINE SERVICE MANUAL LC1P92F (452cc)
About this Manual This service manual was written expressly for Toro service technicians. The Toro Company has made every effort to make the information in this manual complete and correct. Basic shop safety knowledge and mechanical/electrical skills are assumed. The Table of Contents lists the systems and the related topics covered in this manual. An electronic version of this service manual is available on the Toro Dealer Portal.
Chapter 1 – General Service Information 1 Chapter 2 - Engine Service / Maintenance 2 Chapter 3 - Engine Disassembly and Service 3 Chapter 4 - Electrical 4
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Chapter 1 – General Service Information Safety Service Rules Engine Model / Serial Number Location Engine Fastener Torque Specification General Specifications Engine Specifications Troubleshooting 1 2 3 3 4 5 6 7 1
Safety Safety Information This symbol means WARNING or PERSONAL SAFETY INSTRUCTION – read the instruction because it has to do with your safety. Failure to comply with the instruction may result in personal injury or even death. This manual is intended as a service and repair manual only. The safety instructions provided herein are for troubleshooting, service, and repair of the Toro engine. The Toro operator’s manual contains safety information and operating tips for safe operating practices.
1 Service Rules 1. Only use genuine Toro parts and lubrication products. 2. Always install new gaskets, O-rings and seals when assembling engine. 3. Always torque fasteners to specification and in sequence. 4. Always lubricate friction components with clean engine oil or engine assembly lube when assembling engine. Engine Model / Serial Number Location The engine model and serial number are stamped into the crankcase.
Engine Fastener Torque Specifications Oil Drain Valve 7 ft-lbs (10 Nm) Oil Filter Adaptor Bolt 31 ft-lbs (42 Nm) Spark Plug 20 ft-lbs (28 Nm) Connecting Rod Bolts 12 ft-lbs (16 Nm) Crankcase Cover Bolt 20 ft-lbs (28 Nm) Fuel Pump Asm.
1 General Specifications Model Type 1P92F-1 Single Cylinder, 4-Stroke, Forced Air Cooling, OHV Bore X Stroke (mm) 92×68 Displacement (cc) 452 Compression Ratio 8.8 :1 Lubrication Oil Pump with Oil Filter Starting Electric Rotation Counter Clockwise (From P.T.O. Side) Ignition System Transistorized Magneto Ignition Air Cleaner Fuel Type Oil Capacity Foam and Paper Unleaded Gasoline, 87 Octane 34 oz. (1.0 L) Without Filter Change 36 oz. (1.
Engine Specifications Part Item Standard Service Limit Operating RPM 3350 – 3450 RPM － Idle RPM 1700 – 2000 RPM － Warpage － 0.00393” (0.10 mm) 3.6220” - 3.6224” (92-92.01 mm) 3.6259” (92.10 mm) Skirt Outside Diameter 3.620 - 3.621” (91.96-91.975 mm) 3.6196” (91.940 mm) Cylinder Clearance 0.00098 - 0.0017” (0.025-0.045 mm) 0.0032” (0.081 mm) Piston Pin Bore Inside Diameter 0.7870 - 0.7877” (20.002-20.008 mm) 0.7879” (20.01 mm) Piston Pin Clearance 0.00016 - 0.00063” (0.004-0.
1 Troubleshooting Hard Starting / Poor Running - Incorrect Fuel (Level, Age, Octane, Ethanol Content) - Fuel System Contamination and / or Debris in Carburetor - Incorrect Oil Level - Weak Battery / Charging System - Spark Plug (Incorrect Gap, Fouled, Loose or Faulty) - Air Filter Restriction - Air Intake System Leaks - Ignition Coil to Flywheel Gap Incorrect - Weak / No Spark - Incorrect Fuel Solenoid / Fuel Pump Operation - Choke / Governor Linkage - Operating RPM Incorrect - Governor Adjustment Incorrec
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Chapter 2 – Engine Service / Maintenance Engine Oil Change Procedure Air Cleaner Service Spark Plug Service Valve Clearance Inspection and Adjustment Engine Governor – Zero Point Setting Engine Idle Speed / Operating RPM Adjustment Fuel Filter Replacement 9 10 11 12 13 14 15 16 2
Engine Oil Change Procedure 1. Warm engine, then remove the ignition key before changing the engine oil. 2. Drain oil through the drain valve / hose into an approved container. 3. When oil has drained completely, close the oil drain valve. Remove the oil drain hose and wipe up any excess oil on the frame. Note: Properly dispose of used engine oil. 4. Remove the oil filter from the engine and clean the filter adapter gasket surface. 5.
2 Air Cleaner Service 1. Remove the ignition key before servicing the air cleaner. 2. Thoroughly clean the air filter area. 3. Loosen the (2) Cover Knobs and remove the air cleaner cover. 4. Remove the (2) air cleaner retainer nuts and the air cleaner retainer plate. 5. Carefully remove and separate the foam and paper filter elements from the air cleaner housing. Foam Element: 6. Clean the foam element with liquid soap and warm water – rinse and dry it thoroughly.
Spark Plug Service NOTE: Spark plugs of the wrong size or incorrect heat range can cause severe engine damage. High Voltage Ignition Systems can be Dangerous - Use Caution when Servicing Ignition Systems 1. Disconnect the spark plug boot and thoroughly clean the spark plug area. 2. Remove the spark plug from the engine. 3. Inspect the spark plug for excessively worn electrodes, chips or cracks in the insulator, or excessive deposits. 4. Measure the electrode gap and adjust if necessary.
Valve Clearance Inspection and Adjustment NOTE: 2 Valve clearance inspection and adjustment must be done with the engine cold . 1. Rotate Engine to TDC (top-dead-center) of the compression stroke. 2. Remove the valve cover. Be sure both valves are completely closed and the decompression arm is not holding the valve open. 3. Measure the clearance between the rocker arm and the valve stem with a feeler gauge. Intake: 0.0039” (0.10 mm) Exhaust: 0.0059” (0.15 mm) 4.
Engine Governor – Zero Point Setting 1. Loosen but do not remove the governor arm pinch bolt and nut. 2. Move the governor arm to fully open the throttle valve. Firmly hold the governor arm in this position. 3. Rotate the governor shaft fully clockwise and secure it in this position with a pair of pliers. 4. Tighten the governor arm pinch bolt and nut to specification - 7.5 ft-lbs (10 Nm). 5. Verify that the governor arm and throttle valve move freely.
2 Engine Idle Speed 1. Start the engine and allow it to warm to normal operating temperature. 2. With the throttle control in the idle position and the engine idling, adjust the throttle stop screw (A) to achieve the recommended engine idle speed. Engine Idle Speed: 1700 - 2000 RPM A Engine Operating RPM Adjustment 1. Properly set the governor zero point as shown in this manual. 2. Attached an appropriate tachometer to the engine. 3. Start and warm engine. Run engine at MAX RPM. 4.
Fuel Filter and Replacement - Fuel is Extremely Flammable - Use Extreme Caution When Servicing the Fuel System 1. Place a proper fuel drain pan under the fuel filter area. 2. Release the fuel filter / fuel hose clamps (A) and slide them away from the filter. 3. Remove the fuel filter from the (2) fuel hoses. 4. Install new fuel filter and reinstall the fuel hose clamps (A). Make note of installation direction for proper fuel flow. 5. Verify hose routing and check for leaks. 6.
Chapter 3 - Engine Disassembly and Service Engine Service – Upper End 18-25 Air Cleaner and Muffler Exploded View Starter, Flywheel and Engine Cover Exploded View Carburetor and Linkage Exploded View Carburetor Exploded View Cylinder Head Exploded View and Service Information Valve Spring / Valve Seat / Cylinder Head Specifications Valve Stem / Valve Guide Specifications Valve Seat Reconditioning Engine Service – Lower End 18 19 20 21 22 23 24 25 26-34 Crankcase Exploded View and Service Information
Engine Service – Upper End Air Cleaner and Muffler Exploded View Muffler Air Cleaner Retainer Nuts 6 ft-lbs (8 Nm) Spacer Heat Shield Gasket Air Filter Asm.
3 Starter, Flywheel and Engine Cover Exploded View Flywheel Nut 81 ft-lbs (110 Nm) Fan Shroud Bolts 7 ft-lbs (10 Nm) Ignition Coil and Alternator Bolts 7 ft-lbs (10 Nm) Ignition Coil Alternator Starter Bolts 20 ft-lbs (28 Nm) 19
Carburetor and Linkage Exploded View Governor Arm Governor Spring Governor Rod Throttle Control Asm.
3 Carburetor Exploded View Needle Valve Float Gasket Bowl Bowl Bolt 6 ft-lbs (8 Nm) Gasket Solenoid Screw 3.
Cylinder Head Exploded View and Service Information M F G A E Shield D H Studs 23 ft-lbs (31 Nm) J L K Cylinder Head Gasket I B 7.5 ft-lbs (10 Nm) C Lock Nut 11 ft-lbs (15 Nm) Cylinder Head Bolt Torque Sequence: 1. Initially Torque the (4) Cylinder Head Bolts in a Crisscross Pattern to 10 ft-lbs (14 Nm). 2. Evenly Torque the (4) Cylinder Head Bolts in a Crisscross Pattern to 40 ft-lbs (54 Nm).
Valve Spring Free Length Specification Standard Service Limit 1.555 - 1.594” 1.535” (39.5-40.5 mm) (39.0 mm) Valve Seat Width Inspection Remove carbon deposits from the combustion chamber. Inspect the valve seats for pitting or other damage. Valve Seat Width Specification: Standard Service Limit 0.03149 - 0.0393” 0.0591” (0.8-1.0 mm) (1.5 mm) Cylinder Head Warp Inspection STRAIGHT EDGE - Remove carbon deposits from the combustion chamber.
Valve Stem Inspection Inspect each valve for face irregularities, bending or abnormal wear. Valve Stem Diameter Specification Intake Exhaust Standard Service Limit 0.2584 - 0.2590” 0.2579” (6.565-6.58 mm) (6.550 mm) 0.2577 - 0.2583” 0.2571” (6.545-6.56 mm) (6.530 mm) Valve Guide Inspection Ream the exhaust valve guide to remove any carbon deposits before measuring. Valve Guide ID Specification: Standard Service Limit 0.2362 - 0.2604” 0.2606” (6.0-6.615 mm) (6.
3 Valve Seat Reconditioning 1. Thoroughly clean the combustion chamber and valve seats to remove carbon deposits. 2. Apply a light coat of Prussian Blue or erasable felt-tipped marker ink to the valve faces. 3. Properly install valves, springs and keepers. Manually open the valves, then and snap them closed against their seats several times. Be sure the valves do not rotate on the seat. Remove the valve assemblies. The transferred marking compound will show any area of the seat that is not concentric.
Engine Service – Lower End Crankcase Exploded View and Service Information A B C D E F G H I J K L M N O P Q R S T U V W X Y Important: 7 ft-lbs (10Nm) A Oil Seal Breather Reed Valve Asm. Governor Shaft Oil Seal Pin / Clip Washer Bearing (2) Balance Shaft (LH and RH) Thrust Washer Camshaft Bearing Key Crankshaft Bearing Gasket Oil Baffle Plate Rubber Oil Deflector Oil Filter Asm. Governor Asm. Gasket Oil Filter Adaptor Bolt and Sealing Washer Oil Seal Oil Drain Valve Oil Pump Asm.
3 Crankshaft / Piston / Exploded View and Service Info Connecting Rod Bolts 12 ft-lbs (16 Nm) Piston Asm.
Piston Connecting Rod Exploded View and Service Information Assembly: Mark Install Rings with Orientation Mark “UP” Stagger the piston ring gap as shown: Top Ring Second Ring Top Ring Oil Ring Second Ring Oil Ring Check, refer to Piston Piston Pin Piston Pin Circlip: Install the circlip gap in the 12:00 Position (circlip gap facing up) Connecting Rod Orientation Align Long end of connecting rod CLIP with piston orientation “triangle” CUT-OUT 28
3 Camshaft and Balance Shaft Timing 1. Install crankshaft. 2. Align crankshaft and camshaft timing marks and install camshaft. 3. Align the left balance shaft timing marks and install the left balance shaft. 4. Align the right balance shaft timing marks and install the right balance shaft.
Crankshaft Bearing Free Play Clean the bearing in solvent and dry it. Spin the bearing by hand and check for play. Replace the bearing if it is noisy or has excessive free play. Piston Pin OD Standard Service Limit 0.7871 - 0.7873” 0.7834” (19.992-19.998 mm) (19.9 mm) Cylinder Taper and Out of Round Inspect cylinder for taper and out of round with a bore gauge.
3 Piston Skirt Outside Diameter Measure and the piston skirt outside diameter 10mm from the skirt base and 90°to piston pin hole. Standard Service Limit 3.620 - 3.621” 3.6196” (91.96-91.975 mm) (91.940 mm) Piston to Cylinder Clearance Specification Standard Service Limit 0.00098 - 0.0017” 0.0032” (0.025-0.045 mm) (0.081 mm) Piston Ring to Groove Clearance Standard Service Limit Top/ 0.00079 - 0.00236” 0.00433” Middle (0.02-0.06 mm) (0.
Piston Ring End Gap Standard Service Limit 0.0059 - 0.0118” 0.0137” (0.15-0.30 mm) (0.35 mm) Use the piston to position the rings squarely 1” down from the top of the cylinder. Connecting Rod Small End ID Standard Service Limit 0.79 - 0.788” 0.7881” (20.07-20.018 mm) (20.02 mm) . Connecting Rod Big End ID Standard Service Limit 1.4179 - 1.4183” 1.4185” (36.015-36.025 mm) (36.
3 Crankshaft Pin OD Standard Service Limit 1.417 - 1.4165” 1.415” (35.966-35.981 mm) (35.946 mm) Connecting Rod Big End Side Clearance Standard Service Limit 0.00079 - 0.0138” 0.00157” (0.02-0.35 mm) (0.4 mm) Connecting Rod Big End Oil Clearance 1. Clean oil from the crankshaft and connecting rod. 2. Use plastic gauge style measuring tool in accordance to the manufactures instructions to measure the oil clearance. Connecting Rod Bolt Torque: 9.5 ft-lbs (13 Nm) Standard Service Limit 0.
Camshaft Lobe Specifications Intake Exhaust Standard Service Limit 1.282 - 1.284” 1.276” (32.563-32.603 mm) (32.40 mm) 1.262 - 1.264” 1.256” (32.049-32.099 mm) (31.9 mm) Camshaft Journal OD Standard Service Limit 0.6298 - 0.6293” 0.6266” (15.996-15.984 mm) (15.916 mm) Check the camshaft bearing journal for scoring, wear or damage. NOTE: Verify that the decompression mechanism moves freely.
Chapter 4 – Electrical System Information Ignition Coil Gap Adjustment Ignition Coil Resistance Inspection Spark Testing Fuel Solenoid Charging System Specifications 36 36 37 37 38 35 4
Ignition Coil Gap Adjustment High Voltage Ignition Systems can be Dangerous - Use Caution when Servicing Ignition Systems 1. Install the ignition coil and lightly tighten the ignition coil mounting bolts. 2. Rotate engine so ignition coil is aligned with the magnet portion of the flywheel. 3. Insert the feeler gauge between the flywheel and coil. 4. Adjust the ignition coil gap at both side of the coil. 5. Sufficiently tighten the mounting bolts. Ignition Coil Gap 0.011- 0.019” (.3-.
4 Spark Testing - Fuel is Extremely Flammable - Use Extreme Caution When Servicing the Fuel System - High Voltage Ignition Systems can be Dangerous - Use Caution when Servicing Ignition Systems 1. Remove spark plug cap from the spark plug. 2. Remove the spark plug from the engine. 3. Connect the negative (-) electrode of the spark plug (threaded area) to ground (cylinder head cover). 4. Crank the engine and view the electrode gap. Spark should be present when engine is turning over. 5.
Charging System Specifications Charge Coil(s) Air Gap Measure Between the Magnet Area of the Flywheel and the 0.011- 0.019” (.3-.5 mm) Charge Coil Legs No Load DC Voltage Output @ 3000 RPM 14.5 +/- .5 Volts DC Measure Across Battery Terminals No Load AC Voltage Output @ 3000 RPM Measure Across Stator Leads – Stator Leads Disconnected Charge Coil / Stator Resistance Measure Resistance Across the Two Stator Leads 38 30 VAC 0.
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RESIDENTIAL PRODUCTS Form Number: 492-9234 40
